Patent Publication Number: US-2023155341-A1

Title: Laser device and method of using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Patent Application claims priority to U.S. Provisional Pat. Application No. 63/264,129, filed on Nov. 16, 2021, and entitled “LASER DEVICE AND METHOD OF USING THE SAME.” The disclosure of the prior Application is considered part of and is incorporated by reference into this Patent Application. 
    
    
     BACKGROUND 
     A laser device (a light amplification by stimulated emission of radiation device) is a device that emits light using optical amplification based on receiving an input (e.g., stimulation). Laser devices may be configured to emit coherent electromagnetic waves (e.g., light waves), which may be focused into a beam (e.g., a transmission path). Laser devices may be used to emit electromagnetic waves for applications such as laser cutting, medical treatments, measurement tools, annealing operations, and/or lithography (e.g., photolithography), among other examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIGS.  1 - 3    are diagrams of example of laser devices described herein. 
         FIG.  4    is a diagram of an example environment in which systems and/or methods described herein may be implemented. 
         FIG.  5    is a diagram of example components of one or more devices of  FIG.  1    described herein. 
         FIGS.  6  and  7    are flowcharts of example processes relating to laser devices described herein. 
         FIG.  8    is a diagram of an example lithography system in which systems and/or methods described herein may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     In some cases, a laser device may be configured with an optical crystal (nonlinear optical crystal) disposed between optical components of the laser device. The optical crystal may be configured to receive first electromagnetic waves having a first wavelength and emit second electromagnetic waves having a second wavelength. The optical crystal may be disposed between a first mirror device and a second mirror device, with the first mirror device having a first thin film coating on a surface proximate to the optical crystal and with the second mirror device having a second thin film coating on a surface proximate to the optical crystal. The first thin film coating may be configured to reflect the second electromagnetic waves (e.g., to reflect backwards-emitted second electromagnetic waves toward a forward direction). The second thin film coating may be configured to pass forward-emitted second electromagnetic waves through the second mirror device and to reflect forward-emitted first electromagnetic waves back toward the optical crystal for an opportunity to stimulate emission of additional second electromagnetic waves. 
     Using a laser device configured with the optical crystal disposed between the first mirror device and the second mirror device may provide manufacturing challenges, may provide energy losses, and/or may have an unnecessarily long length. For example, disposing the first thin film coating and the second thin film coating may provide manufacturing challenges. The first thin film coating and the second thin film coating have a low tolerance for deposition errors because the first thin film coating and the second thin film coating are configured to reflect and/or pass electromagnetic waves based on having thicknesses tuned to the first wavelength and/or the second wavelength. Imprecision in thicknesses may cause errors in electromagnetic waves passed or reflected by the first thin film coating or the second thin film coating. In this way, errors in the first thin film coating or the second thin film coating may cause electromagnetic waves with unintended wavelengths to be emitted from the laser device, which may damage a device targeted by the laser device, such as a substrate of a semiconductor device. Additionally, or alternatively the first thin film coating and the second thin film coating may have a low tolerance for roughness, which may scatter electromagnetic waves. Further, based on spaces between the optical crystal and the first mirror device and the second mirror device, the laser device may lose energy (e.g., from scattering in the laser device and/or from colliding with particles, among other examples). Still further, the laser device may have an unnecessarily long cavity, which may be an inefficient use of space in a facility that uses the laser device (e.g., a semiconductor manufacturing facility). In this way, the laser device may consume an unnecessarily high amount of energy to compensate for energy losses, the facility may use resources to reduce energy losses (e.g., soaking the laser device with nitrogen gas to reduce particles between the optical crystal and the first mirror device and the second mirror device, among other examples), and/or manufacturing resources may be unnecessarily consumed based on errors in the first thin film coating or the second thin film coating. 
     Some implementations described herein provide techniques and apparatuses for using an optical crystal as a resonator for a laser device. In some implementations, the optical crystal may be configured with one or more thin film coatings at one or more ends of the optical crystal (e.g., a backwards end and/or a forward end along a transmission path of the laser device). In this way, the optical crystal may be configured to reflect backwards-traveling second electromagnetic waves toward a forward direction (e.g., via internal reflection at a back end of the optical crystal) and to emit forwards-traveling second electromagnetic waves (e.g., traveling within the optical crystal) from a forward end of the optical crystal. In some implementations, the optical crystal may be configured to reflect forwards-traveling first electromagnetic waves (e.g., traveling within the optical crystal) and to reflect backwards-traveling first electromagnetic waves (e.g., traveling within the optical crystal). In this way, mirror devices having thin film coatings surrounding the optical crystal may be unnecessary. This may allow a manufacturing process for the laser device to avoid unnecessary cost and consumption of resources to provide the mirror devices having thin film coatings. Additionally, the first electromagnetic waves and the second electromagnetic waves may reduce a distance traveled between devices (e.g., between the optical crystal and mirror devices having the thin film coatings), which may reduce energy losses (e.g., by 10%-20% in deep ultraviolet frequencies or by 5%-10% for visible light frequencies, among other examples) from colliding with particles and/or may reduce scattering from thin film coating roughness. In this way, the laser device may have improved energy efficiency and/or reduced manufacturing cost and/or time, among other examples. For example, he laser device may have reduced downtime (e.g., by 2-3%) based on reduced demands of depositing thin film coatings. Additionally, or alternatively, the laser device may have a reduced cavity length (e.g., a 20% reduction), which may conserve space within a tool that includes the laser device. 
       FIG.  1    is a diagram of an example of a laser device  100  described herein. The laser device  100  may include additional elements (e.g., optical elements) not shown, a housing to position elements within the laser device  100 , and/or may be connected to one or more additional devices, such as a controller, a power supply, a time modulator and a spatial modulator (e.g., to control a laser output sequence and a beam shape), an optical filter and grating (e.g., to narrow a laser spectrum), a and/or an input device, among other examples. In some implementations, the housing may include a metal shell and/or a heat sink to reduce thermal loading of the laser device  100 . In some implementations, the laser device  100  may be configured with a temperature control to maintain a threshold temperature of one or more optical crystals of the laser device  100 . In some implementations, the laser device  100  may be configured for metrology, extreme ultraviolet lithography, immersion scanning, laser annealing, and/or a light source, among other examples. 
     As shown in  FIG.  1    the laser device  100  may include a mirror device  102  disposed at a backward end of a cavity of the laser device  100 . The mirror device  102  may be configured to reflect electromagnetic waves (e.g., pump electromagnetic waves) that travel in a backward direction from a gain device  104  and/or from an optical crystal  106  (e.g., a nonlinear optical crystal). The mirror device  102  may be configured to reflect electromagnetic waves having wavelengths associated with the gain device  104  and/or the optical crystal  106 . 
     The gain device  104  may be configured with a population inversion in which electronic and/or molecular energy levels of the gain device  104  are elevated such that a drop in energy levels produce gain device electromagnetic waves within the laser device  100 . The gain device  104  may include a crystal-based material, such as a rare-earth ion, a transition metal ion, yttrium aluminum garnet, yttrium orthovanadate, sapphire, and/or cesium cadmium bromide. The gain device  104  may include a glass material (e.g., silicate or phosphate glass doped with laser-active ions), a gas material (e.g., helium and neon, nitrogen, argon, carbon monoxide, carbon dioxide, or a metal vapor, among other examples), a semiconductor material (e.g., gallium arsenide, indium gallium arsenide, and/or gallium nitride, among other examples), and/or liquid material (e.g., a dye solution), among other examples. The gain device may be disposed between the mirror device  102  and the optical crystal  106 . 
     The optical crystal  106  is configured to receive electromagnetic waves having a wavelength (e.g., from the gain device  104 ) and emit electromagnetic waves having a different wavelength (e.g., a first wavelength of the laser device). The optical crystal  106  may include barium borate, lithium iodate, potassium niobate, monopotassium phosphate, lithium triborate, beta-barium borate, gallium selenide, potassium dihydrogen phosphate, lithium niobate, ammonium dihydrogen phosphate, and/or potassium titanyl phosphate, among other examples. 
     The laser device  100  may include a modulator device  108  configured to modulate the electromagnetic waves emitted from the optical crystal  106  before passing the electromagnetic waves to a mirror device  110 . The mirror device  110  and the mirror device  102  may be linearly spaced from the optical crystal  106  such that the electromagnetic waves emitted from the optical crustal  106  may travel through a vacuum or other gas before interacting with the mirror device  110  or the mirror device  102 . The modulator device  108  may be configured to block transmission of the electromagnetic waves to the mirror device  110  during a timing interval such that the modulator device  108  passes the electromagnetic waves to the mirror device  110  in pulses. For example, the modulator device  108  may allow transmission of the electromagnetic waves during first portions of time and may block transmission of the electromagnetic waves during second portions of time that alternate with the first portions of time. In some implementations, the electromagnetic waves may reflect between the modulator device  108  and one or more of the mirror  102  or the optical crystal  106  when the modulator device  108  blocks the electromagnetic waves, such that during the first portions of time, an increased volume of electromagnetic waves pass through the modulator device  108 . 
     The mirror device  110  may be configured to reflect a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves outside of a configured range of wavelengths (e.g., a wavelength associated with the electromagnetic waves emitted by the optical crystal  106 ) and to pass a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves in the configured range of wavelengths. For example, the mirror device  110  may be configured with a thickness and/or material that couples to the configured range of wavelengths. In this way, the mirror device  110  may reduce an amount of electromagnetic waves, that are not configured to stimulate emission of electromagnetic waves having a desired wavelength, from exiting a first portion  112  of the laser device  100 . 
     In some implementations, the first portion  112  of the laser device  100  may include multiple optical crystals that receive electromagnetic waves of an incoming frequency and generate electromagnetic waves of an outgoing frequency. For example, a first optical crystal may receive electromagnetic waves having a first frequency and may generate electromagnetic waves having a second frequency. A second optical crystal may receive the electromagnetic waves having the second frequency and may generate electromagnetic waves having a third frequency. A third optical crystal may receive the electromagnetic waves having the third frequency and may generate electromagnetic waves having a fourth frequency. In this way, the first portion  112  of the laser device  100  may have any number of optical crystals to convert incoming electromagnetic waves having a first frequency into outgoing waves having a second frequency. 
     After the first portion  112  of the laser device  100  along a transmission path, the laser device  100  may include an optical crystal  114  configured to receive electromagnetic waves emitted by the optical crystal  106  and to emit electromagnetic waves, having a different wavelength, along the transmission path away from the first portion  112 . In some implementations, the electromagnetic waves emitted by the optical crystal  114  may be harmonics of the electromagnetic waves received from the optical crystal  106 . 
     The optical crystal  114  may include a thin film coating  116  on an end of the optical crystal  114  that is proximate to the first portion  112  (e.g., a backward end). The thin film coating  116  may be configured to receive the electromagnetic waves emitted from the optical crystal  106  and to reflect electromagnetic waves (e.g., with a 90% reflection) generated by the optical crystal  114  (e.g., based on receiving the electromagnetic waves emitted from the optical crystal  106 ). For example, the thin film coating  116  may be configured with a thickness and/or material to couple the thin film coating  116  to the electromagnetic waves emitted from the optical crystal  106  so the electromagnetic waves from the optical crystal  106  pass through the thin film coating  116 . 
     In some implementations, the thin film coating  116  may be further configured to internally reflect the electromagnetic waves emitted from the optical crystal  106  (first electromagnetic waves) and/or to internally reflect the electromagnetic waves generated by the optical crystal  114  (second electromagnetic waves) based on the first electromagnetic waves and/or the second electromagnetic waves traveling within the optical crystal  114  in a backward direction. In some implementations, the thin film coating  116  is configured to support internal reflection of the electromagnetic waves generated by the optical crystal  114  (second electromagnetic waves) and to support internal reflection of the electromagnetic waves emitted by the optical crystal  106  based on a wavelength of the first electromagnetic waves, based on a wavelength of the second electromagnetic waves, based on a material of the thin film coating  116  (e.g., a refractive index of the material), and/or based on a thickness T 1  of the thin film coating  116 . 
     The optical crystal  114  may include a thin film coating  118  on an end of the optical crystal  114  that is distal from the first portion  112  (e.g., a forward end). The thin film coating  118  may be configured to emit the electromagnetic waves generated by the optical crystal  114  and/or may be configured to reflect electromagnetic waves emitted from the optical crystal  106 . 
     In some implementations, the thin film coating  118  may be further configured to emit the electromagnetic waves emitted from the optical crystal  114  and/or to internally reflect the electromagnetic waves emitted from the optical crystal  106  based on the first electromagnetic waves and the second electromagnetic waves traveling within the optical crystal  114  in a forward direction. In some implementations, the thin film coating  118  is configured to support emission of the electromagnetic waves emitted from the optical crystal  114  and to support internal reflection of the electromagnetic waves emitted from the optical crystal  106  based on a wavelength of the first electromagnetic waves, based on a wavelength of the second electromagnetic waves, based on a material of the thin film coating  118  (e.g., a refractive index), and/or based on a thickness T 2  of the thin film coating  118 . 
     In some implementations, the thin film coating  116  may have material and/or thickness such as a metal (e.g., aluminum, silver, gold, among other examples) or a dielectric (e.g., SiO 2 , MgF 2 , YF 3 , LaF 3 , Al 2 O 3 , CeF 3 , Y 2 O 3 , HfO 2 , TiO 2 , CeF 3 , YF 3 , ZnS, ZnO, ZnSe, LaTiO 3 , ZrO 2 , among other examples) that are configured for anti-reflection of electromagnetic waves emitted by the optical crystal  106  and for high reflection of electromagnetic waves emitted by the optical crystal  114  to form a resonator. In some implementations, a thickness of the thin film coating  116  may be less than 1 micrometer. The thin film coating  116  may have a refractive index in a range of approximately 1.2 to approximately 2.7. The optical crystal  114  may have a refractive index in a range of approximately 1.4 to approximately 1.7. 
     The multi-film coating (e.g., the thin film coating  116  and the thin film coating  118 ) may achieve anti-reflection or high reflection based on interference. For example, the thin film coatings  116  and  118  may be configured to cause destructive interference for electromagnetic waves emitted by the optical crystal  106  and constructive interference for electromagnetic waves emitted by the optical crystal  114 . Therefore, the thin film coating  116  and the thin film coating  118  may be formed with a thickness and refractive index to fine-tune a reflection spectrum. 
     The optical crystal  114  with the thin film coating  116  and the thin film coating  118  may be part of a second portion  120  of the laser device  100 . The second portion  120  is further along the transmission path of the laser device  100  than the first portion  112 . In some implementations, the second portion  120  of the laser device  100  may include multiple optical crystals that receive electromagnetic waves of an incoming frequency and generate electromagnetic waves of an outgoing frequency. For example, a first optical crystal may receive electromagnetic waves having a first frequency and may generate electromagnetic waves having a second frequency. A second optical crystal may receive the electromagnetic waves having the second frequency and may generate electromagnetic waves having a third frequency. A third optical crystal may receive the electromagnetic waves having the third frequency and may generate electromagnetic waves having a fourth frequency. In this way, the second portion  120  of the laser device  100  may have any number of optical crystals to convert incoming electromagnetic waves having a first frequency into outgoing waves having a second frequency. 
     In an example operation of the laser device  100 , the optical crystal  106  may emit first electromagnetic waves  122 . The first electromagnetic waves  122  may travel in a forward direction, towards the second portion  120  of the laser device  100  (e.g., towards the optical crystal  114 ). In some implementations, a portion of the first electromagnetic waves  122  may travel in a backwards direction and may be reflected by the mirror device  102  such that the portion of the first electromagnetic waves  122  travel in the forward direction. 
     The optical crystal  114  receives the first electromagnetic waves  122  via the thin film coating  116  and emits the second electromagnetic waves  124  based on receiving the first electromagnetic waves  122 . In some implementations, the first electromagnetic waves  122  may enter the optical crystal  114  and stimulate generation of the second electromagnetic waves  124  within the optical crystal  114 . In some implementations, a portion of the first electromagnetic waves  122  within the optical crystal  114  may travel across the optical crystal  114  and may be internally reflected by the thin film coating  118  such that the portion of the first electromagnetic waves  122  travel back across the optical crystal  114  with an additional opportunity to stimulate generation of the second electromagnetic waves  124 . In this way, the optical crystal  114  may use stimulation from the first electromagnetic waves to generate and emit the second electromagnetic waves  124  with a reduced amount of traveling of the first electromagnetic waves  122  and the second electromagnetic waves  124  outside of the optical crystal  114  during stimulation. 
     In some implementations, the gain device  104  receives an input signal  126  to configure the population inversion for the gain device  104 . In some implementations, the input signal  126  may include electrical signals configured for electron excitement within the gain device  104 . The electron excitement within the gain device  104  may cause the gain device  104  to emit electromagnetic waves that cause electron excitement within the optical crystal  106  and/or stimulate emission of the first electromagnetic waves  122  shown in  FIG.  1   . In some implementations, the modulator device  108  receives a control signal  128  to cause the modulator device  108  to form pulses of the first electromagnetic waves  122  before providing the first electromagnetic waves  122  to the second portion  120 . 
       FIG.  2    is a diagram of an example of a laser device  200  described herein. The laser device  200  shown in  FIG.  2    may include, or may be included in, a laser device  100 . The laser device  200  may include additional elements (e.g., optical elements) not shown, a housing to position elements within the laser device  200 , and/or may be connected to one or more additional devices, such as a controller and/or an input device, among other examples. Devices and other elements of the laser device  200  may have features, configurations, and/or materials corresponding to devices or other elements of the laser device  100 . 
     As shown in  FIG.  2    the laser device  200  may include a mirror device  102  disposed at a backward end of a cavity of the laser device  200 . The mirror device  102  may be configured to reflect electromagnetic waves (e.g., pump electromagnetic waves) that travel in a backward direction from a gain device  104  and/or from an optical crystal  106  (e.g., a nonlinear optical crystal). The mirror device  102  may be configured to reflect electromagnetic waves having wavelengths associated with the gain device  104  and/or the optical crystal  106 . 
     The gain device  104  may be configured with a population inversion in which electronic and/or molecular energy levels of the gain device  104  are elevated such that a drop in energy levels produce gain device electromagnetic waves within the laser device  200 . The gain device  104  may include a crystal-based material, such as a rare-earth ion, a transition metal ion, yttrium aluminum garnet, yttrium orthovanadate, sapphire, and/or cesium cadmium bromide. The gain device  104  may include a glass material (e.g., silicate or phosphate glass doped with laser-active ions), a gas material (e.g., helium and neon, nitrogen, argon, carbon monoxide, carbon dioxide, or a metal vapor, among other examples), a semiconductor material (e.g., gallium arsenide, indium gallium arsenide, and/or gallium nitride, among other examples), and/or liquid material (e.g., a dye solution), among other examples. The gain device may be disposed between the mirror device  102  and the optical crystal  106 . 
     The optical crystal  106  is configured to receive electromagnetic waves having a wavelength (e.g., from the gain device  104 ) and emit electromagnetic waves having a different wavelength (e.g., a first wavelength of the laser device). The optical crystal  106  may include barium borate, lithium iodate, potassium niobate, monopotassium phosphate, lithium triborate, beta-barium borate, gallium selenide, potassium dihydrogen phosphate, lithium niobate, ammonium dihydrogen phosphate, and/or potassium titanyl phosphate, among other examples. 
     The laser device  200  may include a modulator device  108  configured modulate the electromagnetic waves emitted from the optical crystal before passing the electromagnetic waves to a mirror device  110 . The modulator device  108  may be configured to block transmission of the electromagnetic waves to the mirror device  110  during a timing interval such that the modulator device  108  passes the electromagnetic waves to the mirror device  110  in pulses. 
     The mirror device  110  may be configured to reflect a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves outside of a configured range of wavelengths (e.g., a wavelength associated with the electromagnetic waves emitted by the optical crystal  106 ) and to pass a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves in the configured range of wavelengths. In this way, the mirror device  110  may reduce an amount of electromagnetic waves, that are not configured to stimulate emission of electromagnetic waves having a desired wavelength, from exiting a first portion  112  of the laser device  200 . 
     After the first portion  112  of the laser device  200  along a transmission path, the laser device  200  may include an optical crystal  114  configured to receive electromagnetic waves emitted by the optical crystal  106  and to emit electromagnetic waves, having a different wavelength. The optical crystal  114  may include a thin film coating  116  on an end of the optical crystal  114  that is proximate to the first portion  112  (e.g., a backward end). The thin film coating  116  may be configured to receive the electromagnetic waves emitted from the optical crystal  106  when received via the first portion  112  and to reflect the electromagnetic waves generated by the optical crystal  106  when traveling within the optical crystal  114 . The thin film coating  116  may also be configured to pass the electromagnetic waves generated by the optical crystal  114  (e.g., based on receiving the electromagnetic waves emitted from the optical crystal  106 ). 
     The optical crystal  114  may include a thin film coating  118  on an end of the optical crystal  114  that is distal from the first portion  112  (e.g., a forward end). The thin film coating  118  may be configured to reflect the electromagnetic waves generated by the optical crystal  114  and/or emitted from the optical crystal  106 . In some implementations, the thin film coating  118  has a manufacturing tolerance (e.g., for thickness and/or roughness) that is greater than a manufacturing tolerance for the thin film coating  116 . 
     In some implementations, the thin film coating  118  includes two or more angled surfaces that may (e.g., optionally) have reflective films  118   a  and  118   b  disposed thereon. The two or more angled surfaces may be formed with angles that are symmetric about a logical axis  130  that is parallel to a transmission path in a direction from the first portion  112  to the second portion  120  of the laser device. In some implementations, the two or more angled surfaces may be angled, relative to a transmission path within the optical crystal  114 , such that the first electromagnetic waves will internally refract. The total internal reflection angle of nonlinear optical crystal may be in a range of approximately 40 to approximately 70 degrees. Therefore, the distal end of crystal can achieve total internal reflection so long as the angle is greater than 70 degrees. In this way, the optical crystal  114  may not need the thin film coating  118 , which may be omitted. 
     In some implementations, the laser device  200  further includes a beam splitter  202  disposed along a transmission path after emission of the second electromagnetic waves via the optical crystal  114 . In some implementations, the beam splitter  202  may be configured to split the second electromagnetic waves based on reflecting (e.g., in a different direction than a transmission path between the optical crystal  106  to the optical crystal  114 ) a portion  124   a  of the second electromagnetic waves and passing a portion  124   b  of the second electromagnetic waves. 
     The beam splitter  202  and the optical crystal  114  with the thin film coating  116  and the thin film coating  118  may be part of a second portion  120  of the laser device  200 . The second portion  120  is further along the transmission path of the laser device  200  than the first portion  112 . 
     In an example operation of the laser device  200 , the optical crystal  106  may emit the first electromagnetic waves  122 . The first electromagnetic waves  122  may travel in a forward direction, towards the second portion  120  of the laser device  200  (e.g., towards the optical crystal  114 ). In some implementations, a portion of the first electromagnetic waves  122  may travel in a backwards direction and may be reflected by the mirror device  102  such that the portion of the first electromagnetic waves  122  travel in the forward direction. 
     The optical crystal  114  receives the first electromagnetic waves  122 , which may previously travel through the beam splitter  202 , via the thin film coating  116  and emits the second electromagnetic waves  124  based on receiving the first electromagnetic waves  122 . The second electromagnetic waves  124  and/or the first electromagnetic waves  122  (collectively, the electromagnetic waves) may reflect off the two or more angled surfaces having reflective films  118   a  and  118   b  disposed thereon. Based on the two or more angled surfaces being formed with angles that are symmetric about the logical axis  130 , the electromagnetic waves may be reflected such that the electromagnetic waves travel in a direction that is opposite a direction that the electromagnetic waves travel before reflecting off the two or more angled surfaces. 
     The second electromagnetic waves  124  may exit the optical crystal  114  based on selection by the thin film coating  116  and the first electromagnetic waves  122  may be internally reflected by the thin film coating  116 . The second electromagnetic waves  124  may be split using the beam splitter  202  after emission by the optical crystal  114 . The portion  124   a  may be reflected by the beam splitter  202  to a direction that is different from a transmission direction of the laser device  200 . 
     In some implementations, the first electromagnetic waves  122  may enter the optical crystal  114  and stimulate generation of the second electromagnetic waves  124  within the optical crystal  114 . In some implementations, a portion of the first electromagnetic waves  122  within the optical crystal  114  may travel across the optical crystal  114 , off the thin film coating  118 , and then may be internally reflected by the thin film coating  116  such that the portion of the first electromagnetic waves  122  travel back across the optical crystal  114  with an additional opportunity to stimulate generation of the second electromagnetic waves  124 . In this way, the optical crystal  114  may use stimulation from the first electromagnetic waves to generate and emit the second electromagnetic waves  124  with a reduced amount of traveling of the first electromagnetic waves  122  and the second electromagnetic waves  124  outside of the optical crystal  114  during stimulation. Additionally, or alternatively, the optical crystal  114  may have an effective length (e.g., associated with an amount of the second electromagnetic waves expected to be emitted) that is greater than an actual length of the optical crystal  114 . For example, the effective length maybe approximately double the actual length. 
     In some implementations, the gain device  104  receives an input signal  126  to configure the population inversion for the gain device  104 . In some implementations, the input signal  126  may include electrical signals configured to electron excitement within the gain device  104 . The electron excitement within the gain device  104  may cause the gain device  104  to emit electromagnetic waves that cause electron excitement within the optical crystal  106  and/or stimulate emission of the first electromagnetic waves  122  shown in  FIG.  2   . In some implementations, the modulator device  108  receives a control signal  128  to cause the modulator device  108  to form pulses of the first electromagnetic waves  122  before providing the first electromagnetic waves  122  to the second portion  120 . 
       FIG.  3    is a diagram of an example of a laser device  300  described herein. The laser device  300  shown in  FIG.  3    may include, or may be included in a laser device  100 . The laser device  300  may include additional elements (e.g., optical elements) not shown, a housing to position elements within the laser device  300 , and/or may be connected to one or more additional devices, such as a controller and/or an input device, among other examples. 
     As shown in  FIG.  3    the laser device  300  may include a mirror device  102  disposed at a backward end of a cavity of the laser device  300 . The mirror device  102  may be configured to reflect electromagnetic waves (e.g., pump electromagnetic waves) that travel in a backward direction from a gain device  104  and/or from an optical crystal  106  (e.g., a nonlinear optical crystal). The mirror device  102  may be configured to reflect electromagnetic waves having wavelengths associated with the gain device  104  and/or the optical crystal  106 . 
     The gain device  104  may be configured with a population inversion in which electronic and/or molecular energy levels of the gain device  104  are elevated such that a drop in energy levels produce gain device electromagnetic waves within the laser device  300 . The gain device  104  may include a crystal-based material, such as a rare-earth ion, a transition metal ion, yttrium aluminum garnet, yttrium orthovanadate, sapphire, and/or cesium cadmium bromide. The gain device  104  may include a glass material (e.g., silicate or phosphate glass doped with laser-active ions), a gas material (e.g., helium and neon, nitrogen, argon, carbon monoxide, carbon dioxide, or a metal vapor, among other examples), a semiconductor material (e.g., gallium arsenide, indium gallium arsenide, and/or gallium nitride, among other examples), and/or liquid material (e.g., a dye solution), among other examples. The gain device may be disposed between the mirror device  102  and the optical crystal  106 . 
     The optical crystal  106  is configured to receive electromagnetic waves having a wavelength (e.g., from the gain device  104 ) and emit electromagnetic waves having a different wavelength (e.g., a first wavelength of the laser device). The optical crystal  106  may include barium borate, lithium iodate, potassium niobate, monopotassium phosphate, lithium triborate, beta-barium borate, gallium selenide, potassium dihydrogen phosphate, lithium niobate, ammonium dihydrogen phosphate, and/or potassium titanyl phosphate, among other examples. 
     The laser device  300  may include a modulator device  108  configured modulate the electromagnetic waves emitted from the optical crystal before passing the electromagnetic waves to a mirror device  110 . The modulator device  108  may be configured to block transmission of the electromagnetic waves to the mirror device  110  during timing interval such that the modulator device  108  passes the electromagnetic waves to the mirror device  110  in pulses. 
     As shown in  FIG.  3   , a polarizer device  302  may be disposed between the modulator device  108  and the mirror device  110 . In this way, the laser device  300  may be configured to polarize the electromagnetic waves emitted by the optical crystal  106  before providing the electromagnetic waves to the optical crystal  114 . Devices and other elements of the laser device  300  may have features, configurations, and/or materials corresponding to devices or other elements of the laser device  100  and/or the laser device  200 . 
     The mirror device  110  may be configured to reflect a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves outside of a configured range of wavelengths (e.g., a wavelength associated with the electromagnetic waves emitted by the optical crystal  106 ) and to pass a high proportion (e.g., approximately 98% and/or an amount greater than or equal to 90%) of electromagnetic waves in the configured range of wavelengths. In this way, the mirror device  110  may reduce an amount of electromagnetic waves, that are not configured to stimulate emission of electromagnetic waves having a desired wavelength, from exiting a first portion  112  of the laser device  300 . 
     After the first portion  112  of the laser device  300  along a transmission path, the laser device  300  may include an optical crystal  114  configured to receive electromagnetic waves emitted by the optical crystal  106  and to emit electromagnetic waves, having a different wavelength. The optical crystal  114  may include a thin film coating  116  on an end of the optical crystal  114  that is proximate to the first portion  112  (e.g., a backward end). The thin film coating  116  may be configured to receive the electromagnetic waves emitted from the optical crystal  106  when received via the first portion  112  and to reflect the electromagnetic waves generated by the optical crystal  106  when traveling within the optical crystal  114 . The thin film coating  116  may also be configured to pass the electromagnetic waves generated by the optical crystal  114  (e.g., based on receiving the electromagnetic waves emitted from the optical crystal  106 ). 
     The optical crystal  114  may include a thin film coating  118  on an end of the optical crystal  114  that is distal from the first portion  112  (e.g., a forward end). The thin film coating  118  may be configured to reflect the electromagnetic waves generated by the optical crystal  114  and/or emitted from the optical crystal  106 . In some implementations, the thin film coating  118  has a manufacturing tolerance (e.g., for thickness and/or roughness) that is greater than a manufacturing tolerance for the thin film coating  116 . 
     In some implementations, the thin film coating  118  includes two or more angled surfaces having reflective films  118   a  and  118   b  disposed thereon. The two or more angled surfaces may be formed with angles that are symmetric about a logical axis  130  that is parallel to a transmission path in a direction from the first portion  112  to the second portion  120  of the laser device. 
     In some implementations, the laser device  300  further includes a beam splitter  304  disposed along a transmission path after emission of the second electromagnetic waves via the optical crystal  114 . In some implementations, the beam splitter  304  may be configured to reflect the second electromagnetic waves based on the second electromagnetic waves being polarized. 
     The beam splitter  304  and the optical crystal  114  with the thin film coating  116  and the thin film coating  118  may be part of a portion  120  of the laser device  300 . The portion  120  is further along the transmission path of the laser device  300  than the first portion  112 . 
     In an example operation of the laser device  300 , the optical crystal  106  may emit the first electromagnetic waves  122 . The first electromagnetic waves  122  may travel in a forward direction, towards the second portion  120  of the laser device  300  (e.g., towards the optical crystal  114 ). In some implementations, a portion of the first electromagnetic waves  122  may travel in a backwards direction and may be reflected by the mirror device  102  such that the portion of the first electromagnetic waves  122  travel in the forward direction. 
     The optical crystal  114  receives the first electromagnetic waves  122 , having a polarization and/or having previously traveled through the beam splitter  304 , via the thin film coating  116  and emits the second electromagnetic waves  124  based on receiving the first electromagnetic waves  122 . The second electromagnetic waves  124  and/or the first electromagnetic waves  122  (collectively, the electromagnetic waves) may reflect off the two or more angled surfaces having reflective films  118   a  and  118   b  disposed thereon. Based on the two or more angled surfaces being formed with angles that are symmetric about the logical axis  130 , the electromagnetic waves may be reflected such that the electromagnetic waves travel in a direction that is opposite a direction that the electromagnetic waves travel before reflecting off the two or more angled surfaces. 
     The second electromagnetic waves  124  may exit the optical crystal  114  based on selection by the thin film coating  116  and the first electromagnetic waves  122  may be internally reflected by the thin film coating  116 . The second electromagnetic waves  124  may be reflected using the beam splitter  304  after emission by the optical crystal  114 . The second electromagnetic waves  124  may be reflected by the beam splitter  304  to a direction that is different from a transmission direction of the laser device  300 . In some implementations, the first electromagnetic waves  124  may be reflected (e.g., with little or no splitting) based on the beam splitter being a polarized beam splitter and based on the second electromagnetic waves  124  being generated with a polarization. The second electromagnetic waves  124  may be generated with a polarization based on the first electromagnetic waves  122  being polarized by the polarizer device  302 . 
     In some implementations, the first electromagnetic waves  122  may enter the optical crystal  114  and stimulate generation of the second electromagnetic waves  124  within the optical crystal  114 . In some implementations, a portion of the first electromagnetic waves  122  within the optical crystal  114  may travel across the optical crystal  114 , off the thin film coating  118 , and then may be internally reflected by the thin film coating  116  such that the portion of the first electromagnetic waves  122  travel back across the optical crystal  114  with an additional opportunity to stimulate generation of the second electromagnetic waves  124 . In this way, the optical crystal  114  may use stimulation from the first electromagnetic waves to generate and emit the second electromagnetic waves  124  with a reduced amount of traveling of the first electromagnetic waves  122  and the second electromagnetic waves  124  outside of the optical crystal  114  during stimulation. Additionally, or alternatively, the optical crystal  114  may have an effective length (e.g., associated with an amount of the second electromagnetic waves expected to be emitted) that is greater than an actual length of the optical crystal  114 . For example, the effective length maybe approximately double the actual length. 
     In some implementations, the gain device  104  receives an input signal  126  to configure the population inversion for the gain device  104 . In some implementations, the input signal  126  may include electrical signals configured to electron excitement within the gain device  104 . The electron excitement within the gain device  104  may cause the gain device  104  to emit electromagnetic waves that cause electron excitement within the optical crystal  106  and/or stimulate emission of the first electromagnetic waves  122  shown in  FIG.  3   . In some implementations, the modulator device  108  receives a control signal  128  to cause the modulator device  108  to form pulses of the first electromagnetic waves  122  before providing the first electromagnetic waves  122  to the second portion  120 . 
       FIG.  4    is a diagram of an example environment in which systems and/or methods described herein may be implemented.  FIG.  4    illustrates an example system  400  (e.g., an inspection tool) in which laser device  100 , laser device  200 , and/or laser device  300  may be used. 
     As shown in  FIG.  4   , a laser device  402  (e.g., the laser device  100 , the laser device  200 , and/or the laser device  300 ) may emit electromagnetic waves toward an object to be inspected. In some implementations, the laser device  402  may have a length (e.g., in a direction along a path of the electromagnetic waves) that is reduced based on including one or more features described in connection with the laser device  100 , the laser device  200 , and/or the laser device  300 . In some implementations, the laser device  402  may consume a reduced amount of power resources and/or may generate an increased amount of electromagnetic waves based on including one or more features described in connection with the laser device  100 , the laser device  200 , and/or the laser device  300 . In some implementations, the laser device  402  may have a reduced frequency bandwidth of electromagnetic waves based on including one or more features described in connection with the laser device  100 , the laser device  200 , and/or the laser device  300 . In this way, the laser device  402  may produce a set of electromagnetic waves that provide an inspection tool with an improved consistency of results (e.g., based on the electromagnetic waves refracting and/or reflecting off of an object with improved consistency. 
     The electromagnetic waves may pass through an intensity modulator  404 , a filter  406 , and/or a polarizer  408 . In some implementations, the intensity modulator  404  may control a power of the electromagnetic waves directed toward an object. In some implementations, the filter  406  may filter out frequencies from the electromagnetic waves that are outside of a range of frequencies. For example, the filter  406  may couple to a desired frequency, such that electromagnetic waves at the desired frequency, or within a threshold difference from the desired frequency, pass through the filter  406 . The polarizer  408  may polarize the electromagnetic waves such that the electromagnetic waves have a common polarization (e.g., a horizontal polarization or a vertical polarization). In this way, the electromagnetic waves may have an improve consistency in refractions off an object. Additionally, or alternatively, the polarizer  408  may be configured, along with the intensity modulator  404 , to reduce a power of the electromagnetic waves to a desired power range. 
     The electromagnetic waves may be emitted by the laser device  402  and may pass through the intensity modulator  404 , the filter  406 , and/or the polarizer  408  before interacting with an object  410  under inspection (e.g., placed on an inspection surface  412 ). The electromagnetic waves may by emitted toward the object such that the electromagnetic waves may reflect and/or refract off of one or more surfaces of the object  410 . Based at least in part on reflections and/or refractions off of the one or more surfaces of the object  410 , the system may detect features of the object  410 , such as a topography of the object  410 . In some implementations, the object  410  may be a semiconductor chip after manufacturing (e.g., a device under test), or may be a wafer or semiconductor chip at an intermediate state of a manufacturing process. 
     After reflecting or refracting off of the one or more surfaces of the object  410 , the electromagnetic waves may pass through a compensator  414  and/or an analyzer  416 . The compensator  414  and the analyzer  416  may form or include a polarizer compensator sample analyzer that enhances contrast for image inspection and forms an image on a photo-sensitive element of the system. For example, the compensator  414  and the analyzer  416  may enhance reception of the electromagnetic waves to form an image on a detector  418 . In some implementations, the image may be a grayscale image with improved resolution and/or contrast based at least in part on the compensator and/or analyzer. The detector  418  may provide, via a communication medium  420 , the image or associated information to a data acquisition device  422 . The data acquisition device  422  may include a processor, memory, and/or one or more other elements that support analyzing and/or storing images of the object  410  based on reception of the electromagnetic waves emitted by the laser device  402 . The data acquisition device  422  may provide the images to another device and/or may report on a status (e.g., passing inspection or failing inspection) associated with the object  410 . 
       FIG.  5    is a diagram of example components of a device  500 , which may correspond to a controller of the laser device  100 ,  200 ,  300 , or  402 , a controller of the system  400 , and/or the data acquisition device  422 . In some implementations, controller of the laser device  100 ,  200 ,  300 , or  402 , the controller of the system  400 , and/or the data acquisition device  422  may include one or more devices  500  and/or one or more components of device  500 . As shown in  FIG.  5   , device  500  may include a bus  510 , a processor  520 , a memory  530 , an input component  540 , an output component  550 , and a communication component  560 . 
     Bus  510  includes one or more components that enable wired and/or wireless communication among the components of device  500 . Bus  510  may couple together two or more components of  FIG.  5   , such as via operative coupling, communicative coupling, electronic coupling, and/or electric coupling. Processor  520  includes a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. Processor  520  is implemented in hardware, firmware, or a combination of hardware and software. In some implementations, processor  520  includes one or more processors capable of being programmed to perform one or more operations or processes described elsewhere herein. 
     Memory  530  includes volatile and/or nonvolatile memory. For example, memory  530  may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). Memory  530  may include internal memory (e.g., RAM, ROM, or a hard disk drive) and/or removable memory (e.g., removable via a universal serial bus connection). Memory  530  may be a non-transitory computer-readable medium. Memory  530  stores information, instructions, and/or software (e.g., one or more software applications) related to the operation of device  500 . In some implementations, memory  530  includes one or more memories that are coupled to one or more processors (e.g., processor  520 ), such as via bus  510 . 
     Input component  540  enables device  500  to receive input, such as user input and/or sensed input. For example, input component  540  may include a touch screen, a keyboard, a keypad, a mouse, a button, a microphone, a switch, a sensor, a global positioning system sensor, an accelerometer, a gyroscope, and/or an actuator. Output component  550  enables device  500  to provide output, such as via a display, a speaker, and/or a light-emitting diode. Communication component  560  enables device  500  to communicate with other devices via a wired connection and/or a wireless connection. For example, communication component  560  may include a receiver, a transmitter, a transceiver, a modem, a network interface card, and/or an antenna. 
     Device  500  may perform one or more operations or processes described herein. For example, a non-transitory computer-readable medium (e.g., memory  530 ) may store a set of instructions (e.g., one or more instructions or code) for execution by processor  520 . Processor  520  may execute the set of instructions to perform one or more operations or processes described herein. In some implementations, execution of the set of instructions, by one or more processors  520 , causes the one or more processors  520  and/or the device  500  to perform one or more operations or processes described herein. In some implementations, hardwired circuitry may be used instead of or in combination with the instructions to perform one or more operations or processes described herein. Additionally, or alternatively, processor  520  may be configured to perform one or more operations or processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software. 
     The number and arrangement of components shown in  FIG.  5    are provided as an example. Device  500  may include additional components, fewer components, different components, or differently arranged components than those shown in  FIG.  5   . Additionally, or alternatively, a set of components (e.g., one or more components) of device  500  may perform one or more functions described as being performed by another set of components of device  500 . 
       FIG.  6    is a flowchart of an example process  600  relating to laser devices described herein. For example, process  600  relates to using the laser device. In some implementations, one or more process blocks of  FIG.  6    may be performed by one or more laser devices (e.g., laser device  100 , laser device  200 , laser device  300 , and/or laser device  400 ). Additionally, or alternatively, one or more process blocks of  FIG.  6    may be performed by one or more components of device  500 , such as processor  520 , memory  530 , input component  540 , output component  550 , and/or communication component  560 . 
     As shown in  FIG.  6   , process  600  may include receiving an input signal into a first portion of a laser device, the input signal stimulating emission of first electromagnetic waves having a first wavelength (block  610 ). For example, the laser device may receive an input signal  126  into a first portion  112  of the laser device (e.g., laser device  100 ,  200 ,  300 , and/or  400 ), the input signal stimulating emission of first electromagnetic waves  122  having a first wavelength, as described above. 
     As further shown in  FIG.  6   , process  600  may include receiving, via an optical crystal in a second portion of the laser device, the first electromagnetic waves (block  620 ). For example, the laser device may receive, via an optical crystal  114  in a second portion of the laser device, the first electromagnetic waves  122 , as described herein. In some implementations, the optical crystal  114  includes a thin film coating (e.g., thin film coating  116  or  118 ) disposed on an end of the optical crystal  114 . In some implementations, the thin film coating is configured to emit second electromagnetic waves  124  from the optical crystal  114  based on reception of the first electromagnetic waves  122 , and cause internal reflection of the first electromagnetic waves  122  within the optical crystal  114 . 
     As further shown in  FIG.  6   , process  600  may include emitting the second electromagnetic waves via the optical crystal (block  630 ). For example, the laser device may emit the second electromagnetic waves  124  via the optical crystal  114 , as described herein. 
     Process  600  may include additional implementations, such as any single implementation or any combination of implementations described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first implementation, process  600  includes receiving an input (e.g., a control signal  128 ) at a modulator device  108  within the first portion  112  of the laser device, and modulating, by the modulator device  108 , the first electromagnetic waves  122  before reception of the first electromagnetic waves  122  by the optical crystal  114 . 
     In a second implementation, alone or in combination with the first implementation, process  600  includes polarizing the first electromagnetic waves  122  via a polarizer device  302  within the first portion  112  of the laser device. 
     In a third implementation, alone or in combination with one or more of the first and second implementations, process  600  includes reflecting a portion  124   a  of the second electromagnetic waves  124 , via a beam splitter  202  or  304  and after emission from the optical crystal  114 , in a direction that is non-parallel to a transmission path of the first electromagnetic waves  122 . 
     In a fourth implementation, alone or in combination with one or more of the first through third implementations, the end of the optical crystal  114  having the thin film coating  116  disposed thereon is proximate to the first portion  112 , an additional end of the optical crystal  114 , opposite from the end of the optical crystal  114  having the thin film coating  116  disposed thereon, comprises two or more angled surfaces having a reflective film  118   a  and  118   b  disposed thereon, and the reflective film  118   a  and  118   b  is configured to cause internal reflection of the first electromagnetic waves  122  and internal reflection of the second electromagnetic waves  124  from the additional end. 
     Although  FIG.  6    shows example blocks of process  600 , in some implementations, process  600  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  6   . Additionally, or alternatively, two or more of the blocks of process  600  may be performed in parallel. 
       FIG.  7    is a flowchart of an example process  700  relating to laser devices described herein. For example, process  700  relates to using the laser device. In some implementations, one or more process blocks of  FIG.  7    may be performed by one or more semiconductor processing tools (e.g., a deposition tool, an etching tool, and/or wafer/die transport tool). Additionally, or alternatively, one or more process blocks of  FIG.  7    may be performed by one or more components of device  500 , such as processor  520 , memory  530 , input component  540 , output component  550 , and/or communication component  560 . 
     As shown in  FIG.  7   , process  700  may include disposing one or more optical devices within a first portion of a laser device (block  710 ). For example, the one or more semiconductor processing tools may dispose one or more optical devices (e.g., devices  102 - 110  and/or  302 ) within a first portion  112  of a laser device, as described herein. In some implementations, the first portion  112  is configured to emit first electromagnetic waves  122 , having a first wavelength, based on reception of an input signal  126 . 
     As further shown in  FIG.  7   , process  700  may include depositing a thin film coating on an end of an optical crystal, the thin film coating configured to support emission of second electromagnetic waves, having a second wavelength, from the optical crystal based on reception of the first electromagnetic waves, and support internal reflection of the first electromagnetic waves within the optical crystal (block  720 ). For example, the one or more semiconductor processing tools may deposit a thin film coating ( 116  or  118 ) on an end of an optical crystal  114 , as described herein. In some implementations, the thin film coating  116  or  118  is configured to support emission of second electromagnetic waves  124 , having a second wavelength, from the optical crystal  114  based on reception of the first electromagnetic waves  122 , and support internal reflection of the first electromagnetic waves  122  within the optical crystal  114 . 
     As further shown in  FIG.  7   , process  700  may include disposing the optical crystal within a second portion of the laser device (block  730 ). For example, the one or more semiconductor processing tools may dispose the optical crystal  114  within a second portion  120  of the laser device, as described herein. In some implementations, the laser device is configured to provide the first electromagnetic waves to the optical crystal within the second portion of the laser device. 
     Process  700  may include additional implementations, such as any single implementation or any combination of implementations described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first implementation, depositing the thin film coating ( 116  or  118 ) on the end of the optical crystal  114  comprises: depositing the thin film coating on the end of the optical crystal  114  with a thickness T 1  or T 2  to support emission of the second electromagnetic waves  124  from the optical crystal  114  and to support internal reflection of the first electromagnetic waves  122  within the optical crystal  114 , the thickness (T 1  or T 2 ) being based on the first wavelength, the second wavelength, and a material of the thin film coating ( 116  or  118 ). 
     Although  FIG.  7    shows example blocks of process  700 , in some implementations, process  700  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  7   . Additionally, or alternatively, two or more of the blocks of process  700  may be performed in parallel. 
       FIG.  8    is a diagram of an example lithography system  800  described herein. The lithography system  800  includes an extreme ultraviolet (EUV) lithography system or another type of lithography system that is configured to transfer a pattern to a semiconductor substrate using mirror-based optics. The lithography system  800  may be configured for use in a semiconductor processing environment such as a semiconductor foundry or a semiconductor fabrication facility. 
     As shown in  FIG.  8   , the lithography system  800  includes a radiation source  802  and an exposure tool  804 . The radiation source  802  (e.g., an EUV radiation source or another type of radiation source) is configured to generate radiation  806  such as EUV radiation and/or another type of electromagnetic radiation (e.g., light). The exposure tool  804  (e.g., an EUV scanner tool, and EUV exposure tool, or another type of exposure tool) is configured to focus the radiation  806  onto a reflective reticle  808  (or a photomask) such that a pattern is transferred from the reticle  808  onto a semiconductor substrate  810  using the radiation  806 . 
     The radiation source  802  includes a vessel  812  and a collector  814  in the vessel  812 . The collector  814 , includes a curved mirror that is configured to collect the radiation  806  generated by the radiation source  802  and to focus the radiation  806  toward an intermediate focus  816 . The radiation  806  is produced from a plasma that is generated from droplets  818  of a target material (e.g., droplets of a target material including Sn droplets or another type of droplets) being exposed to a laser beam  820 . The droplets  818  are provided across the front of the collector  814  by a droplet generator (DG)  822 . The droplet generator  822  is pressurized to provide a fine and controlled output of the droplets  818 . The laser beam  820  is provided such that the laser beam  820  is focused through a window  824  of the collector  814 . The laser beam  820  is focused onto the droplets  818  which generates the plasma. The plasma produces a plasma emission, some of which is the radiation  806 . 
     The exposure tool  804  includes an illuminator  826  and a projection optics box (POB)  828 . The illuminator  826  includes a plurality of reflective mirrors that are configured to focus and/or direct the radiation  806  onto the reticle  808  so as to illuminate the pattern on the reticle  808 . The plurality of mirrors include, for example, a mirror  830   a  and a mirror  830   b . The mirror  830   a  includes a field facet mirror (FFM) or another type of mirror that includes a plurality of field facets. The mirror  830   b  includes a pupil facet mirror (PFM) or another type of mirror that also includes a plurality of pupil facets. The facets of the mirrors  830   a  and  830   b  are arranged to focus, polarize, and/or otherwise tune the radiation  806  from the radiation source  802  to increase the uniformity of the radiation  806  and/or to increase particular types of radiation components (e.g., transverse electric (TE) polarized radiation, transverse magnetic (TM) polarized radiation). Another mirror  832  (e.g., a relay mirror) is included to direct radiation  806  from the illuminator  826  onto the reticle  808 . 
     The projection optics box  828  includes a plurality of mirrors that are configured to project the radiation  806  onto the semiconductor substrate  810  after the radiation  806  is modified based on the pattern of the reticle  808 . The plurality of reflective mirrors include, for example, mirrors  834   a - 834   f . In some implementations, the mirrors  834   a - 834   f  are configured to focus or reduce the radiation  806  into an exposure field, which may include one or more die areas on the semiconductor substrate  810 . 
     The exposure tool  804  includes a wafer stage  836  (or a substrate stage) configured to support the semiconductor substrate  810 . Moreover, the wafer stage  836  is configured to move (or step) the semiconductor substrate  810  through a plurality of exposure fields as the radiation  806  transfers the pattern from the reticle  808  onto the semiconductor substrate  810 . The wafer stage  836  is included in a bottom module  838  of the exposure tool  804 . The bottom module  838  includes a removable subsystem of the exposure tool  804 . The bottom module  838  may slide out of the exposure tool  804  and/or otherwise may be removed from the exposure tool  804  to enable cleaning and inspection of the wafer stage  836  and/or the components of the wafer stage  836 . The bottom module  838  isolates the wafer stage  836  from other areas in the exposure tool  804  to reduce and/or minimize contamination of the semiconductor substrate  810 . Moreover, the bottom module  838  may provide physical isolation for the wafer stage  836  by reducing the transfer of vibrations (e.g., vibrations in the semiconductor processing environment in which the lithography system  800  is located, vibrations in the lithography system  800  during operation of the lithography system  800 ) to the wafer stage  836  and, therefore, the semiconductor substrate  810 . This reduces movement and/or disturbance of the semiconductor substrate  810 , which reduces the likelihood that the vibrations may cause a pattern misalignment. 
     The exposure tool  804  also includes a reticle stage  840  that is configured to support and/or secure the reticle  808 . Moreover, the reticle stage  840  is configured to move or slide the reticle through the radiation  806  such that the reticle  808  is scanned by the radiation  806 . In this way, a pattern that is larger than the field or beam of the radiation  806  may be transferred to the semiconductor substrate  810 . 
     The lithography system  800  includes a laser source  842 . The laser source  842  may include laser device  100 , laser device  200 , and/or laser device  300 . The laser source  842  is configured to generate the laser beam  820 . The laser source  842  may include a CO 2 -based laser source or another type of laser source. Due to the wavelength of the laser beams generated by a CO 2 -based laser source in an infrared (IR) region, the laser beams may be highly absorbed by tin, which enables the CO 2 -based laser source to achieve high power and energy for pumping tin-based plasma. In some implementations, the laser beam  820  includes a plurality of types of laser beams that the laser source  842  generates using a multi-pulse technique (or a multi-stage pumping technique), in which the laser source  842  generates a pre-pulse laser beam and main-pulse laser beam to achieve greater heating efficiency of tin (Sn)-based plasma to increase conversion efficiency. 
     In an example exposure operation (e.g., an EUV exposure operation), the droplet generator  822  provides the stream of the droplets  818  across the front of the collector  814 . The laser beam  820  contacts the droplets  818 , which causes a plasma to be generated. The laser source  842  generates and provides a pre-pulse laser beam toward a target material droplet in the stream of the droplets  818 , and the pre-pulse laser beam is absorbed by the target material droplet. This transforms the target material droplet into disc shape or a mist. Subsequently, the laser source  842  provides a main-pulse laser beam with large intensity and energy toward the disc-shaped target material or target material mist. Here, the atoms of the target material are neutralized, and ions are generated through thermal flux and shock wave. The main-pulse laser beam pumps ions to a higher charge state, which causes the ions to radiate the radiation  806  (e.g., EUV light). 
     The radiation  806  is collected by the collector  814  and directed out of the vessel  812  and into the exposure tool  804  toward the mirror  830   a  of the illuminator  826 . The mirror  830   a  reflects the radiation  806  onto the mirror  830   b , which reflects the radiation  806  onto the mirror  832  toward the reticle  808 . The radiation  806  is modified by the pattern in the reticle  808 . In other words, the radiation  806  reflects off of the reticle  808  based on the pattern of the reticle  808 . The reflective reticle  808  directs the radiation  806  toward the mirror  834   a  in the projection optics box  828 , which reflects the radiation  806  onto the mirror  834   b . The radiation  806  continues to be reflected and reduced in the projection optics box  828  by the mirrors  834   c - 834   f . The mirror  834   f  reflects the radiation  806  onto the semiconductor substrate  810  such that the pattern of the reticle  808  is transferred to the semiconductor substrate  810 . The above-described exposure operation is an example, and the lithography system  800  may operate according to other EUV techniques and radiation paths that include a greater quantity of mirrors, a lesser quantity of mirrors, and/or a different configuration of mirrors. 
     As indicated above,  FIG.  8    is provided as an example. Other examples may differ from what is described with regard to  FIG.  8   . For example, another example may include additional components, fewer components, different components, or differently arranged components than those shown in  FIG.  8   . Additionally, or alternatively, a set of components (e.g., one or more components) of  FIG.  8    may perform one or more functions described herein as being performed by another set of components. 
     Based on using an optical crystal as a resonator for a laser device with one or more thin film coatings at one or more ends of the optical crystal (e.g., a backwards end or a forward end along a transmission path of the laser device), mirror devices having thin film coatings surrounding the optical crystal may be unnecessary. This may allow a manufacturing process for the laser device to avoid unnecessary cost and consumption of resources to provide the mirror devices having thin film coatings. Additionally, the first electromagnetic waves and the second electromagnetic waves may reduce travel between devices (e.g., between the optical crystal and mirror devices having the thin film coatings), which may reduce energy losses from colliding with particles and/or may reduce scattering from thin film coating roughness. In this way, the laser device may have improved energy efficiency and/or reduced manufacturing cost and/or time, among other examples. 
     As described in greater detail above, some implementations described herein provide a laser device. The laser device includes a first portion of the laser device, at a proximal end of the laser device, that includes one or more optical devices, where the first portion is configured to emit first electromagnetic waves having a first wavelength. The laser device includes a second portion of the laser device, at a distal end of the laser device, that includes an optical crystal configured to receive the first electromagnetic waves and to emit second electromagnetic waves having a second wavelength based on reception of the first electromagnetic waves, where the optical crystal includes a thin film coating disposed on an end of the optical crystal, the thin film coating configured to: support emission of the second electromagnetic waves from the optical crystal, and support internal reflection of the first electromagnetic waves within the optical crystal. 
     As described in greater detail above, some implementations described herein provide a method. The method includes receiving an input signal into a first portion of a laser device, the input signal stimulating emission of first electromagnetic waves having a first wavelength. The method also includes receiving, via an optical crystal in a second portion of the laser device, the first electromagnetic waves. The optical crystal includes a thin film coating disposed on an end of the optical crystal. The thin film coating is configured to emit second electromagnetic waves from the optical crystal based on reception of the first electromagnetic waves and cause internal reflection of the first electromagnetic waves within the optical crystal. The method further includes emitting the second electromagnetic waves via the optical crystal. 
     As described in greater detail above, some implementations described herein provide a method. The method includes disposing one or more optical devices within a first portion of a laser device. The first portion is configured to emit first electromagnetic waves, having a first wavelength, based on reception of an input signal. The method also includes depositing a thin film coating on an end of an optical crystal. The thin film coating is configured to support emission of second electromagnetic waves, having a second wavelength, from the optical crystal based on reception of the first electromagnetic waves, and support internal reflection of the first electromagnetic waves within the optical crystal. The method further includes disposing the optical crystal within a second portion of the laser device, where the laser device is configured to provide the first electromagnetic waves to the optical crystal within the second portion of the laser device. 
     As described in greater detail above, some implementations described herein provide a method. The method includes emitting electromagnetic waves, toward an object to be inspected, by a laser device. The laser device includes a first portion of the laser device, where the first portion configured to emit first electromagnetic waves having a first wavelength. The laser device also includes a second portion of the laser device, where the second portion includes an optical crystal configured to receive the first electromagnetic waves and to emit second electromagnetic waves having a second wavelength based on reception of the first electromagnetic waves. The optical crystal includes a thin film coating disposed on an end of the optical crystal, the thin film coating configured to support emission of the second electromagnetic waves from the optical crystal and to support internal reflection of the first electromagnetic waves within the optical crystal. The method also includes receiving a portion of the electromagnetic waves after reflection or refraction off of one or more surfaces of the object. The method may further include analyzing images of the object based on reception of the electromagnetic waves emitted by the laser device. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.