LIGHT MODULATING DEVICE AND ELECTRONIC APPARATUS USING THE SAME

A light modulating device for modulating incident light in a given wavelength band is provided. The light modulating device may include: a first semiconductor layer; an active layer provided on the first semiconductor layer and having a multiple quantum well structure and a refractive index that is variable according to an electric field applied thereto, and a second semiconductor layer provided on the active layer and including a grating pattern in which a plurality of gratings extending in a first direction are repeatedly arranged in a second direction perpendicular to the first direction. The light modulating device may have high modulation efficiency owing to guided mode resonance by the grating pattern.

BACKGROUND

Apparatuses and methods consistent with example embodiments relate to a light modulating device and an electronic apparatus including the light modulating device.

2. Description of Related Art

Light modulating devices change the properties of incident light such as the transmission/reflection/scattering characteristics, phase, amplitude, polarization, intensity, or path of incident light, and are used in various optical devices. Light modulating devices having various structures have been proposed to control the properties of light in a desired manner within an optical system. For example, liquid crystals having optical anisotropy, microelectromechanical system (MEMS) structures using the micro-mechanical movements of light blocking/reflecting elements, and the like have been used in general light modulating devices. Such light modulating devices have a limited operation response time due to the characteristics of methods of driving the light modulating devices.

Recently, there have been attempts to apply a meta structure to light modulating devices. The term “meta structure” refers to a structure having a thickness, a pattern, or a pitch which is less than the wavelength of incident light. Various light modulating devices configured to modulate incident light by changing the resonance conditions of a meta structure have been proposed, and methods for increasing modulation efficiency have been constantly researched.

SUMMARY

One or more example embodiments provide light modulating devices having improved modulation efficiency.

One or more example embodiments provide electronic apparatuses using light modulating devices.

According to an aspect of an embodiment, a light modulating device for modulating incident light in a given wavelength band is provided, the light modulating device including: a first semiconductor layer; an active layer provided on the first semiconductor layer, the active layer having a multiple quantum well structure and and a refractive index that is variable according to an electric field applied thereto; and a second semiconductor layer provided on the active layer, the second semiconductor layer including a grating pattern in which a plurality of gratings extending in a first direction are repeatedly arranged in a second direction perpendicular to the first direction.

The grating pattern of the second semiconductor layer may form a localized guided mode in the second direction for the incident light in the given wavelength band.

The grating pattern of the second semiconductor layer may have a height and a pitch which are less than a center wavelength of the given wavelength band.

The grating pattern of the second semiconductor layer may have a height and a pitch which are less than half of a center wavelength of the given wavelength band.

The active layer may have an absorption coefficient that is less than 200 cm−1for a light of resonance wavelength at which a reflectance by the grating pattern exhibits a peak value.

The second semiconductor layer may have a first width in the first direction and a second width in the second direction, and a ratio of the second width to the first width may be 10 or more.

Each of the first semiconductor layer, the active layer, and the second semiconductor layer may include a Group III-V compound semiconductor.

The active layer may have the multiple quantum well structure based on InGaAsP/InP, GaAs/InGaAs, or GaN/AIGaN.

The first semiconductor layer may be doped with an N-type dopant, and the second semiconductor layer may be doped with a P-type dopant.

The active layer and the second semiconductor layer may have a structure divided into a plurality of controllable modulation elements that are individually controllable.

The plurality of modulation elements may be arranged with a first pitch in the first direction.

The first pitch may be less than a center wavelength of the given wavelength band.

The plurality of modulation elements may be arranged with a first pitch in the first direction and with a second pitch in the second direction.

The ratio of the second pitch to the first pitch may be 2.5 or more.

The first semiconductor layer may support the plurality of modulation elements in common.

The first semiconductor layer may include a plurality of protruding elements which protrude in a third direction perpendicular to the first direction and the second direction.

The plurality of protruding elements may have a height of 20 nm or more.

The spacing between the plurality of protruding elements may be within a range of about 50 nm to about 500 nm.

According to an aspect of another embodiment, a beam steering device includes: the light modulating device; and a processor configured to control voltages respectively applied to the plurality of modulation elements such that the light modulating device deflects the incident light at a deflection angle within a given angle range.

The processor may time-sequentially vary the voltages such that a predetermined area may be scanned while the deflection angle is time-sequentially varied within the given angle range.

According to an aspect of another embodiment, an electronic apparatus includes: a light source; the beam steering device that scans an object by adjusting a direction of light which may be incident from the light source; a photodetector configured to receive light from the object; and a processor configured to control the beam steering device and process an optical signal received from the photodetector.

According to an aspect of another embodiment, there is provided a light modulating device including: a plurality of modulation elements that are spaced apart from each other at a regular interval, in a first direction, wherein each of the plurality of modulation elements may include: a first semiconductor layer having a grating pattern and doped with a first type of dopant; a second semiconductor layer doped with a second type of dopant; and a quantum well layer that has a multiple quantum well structure, has a refractive index that is variable according to a voltage applied thereto, the quantum well layer being provided between the first semiconductor layer and the second semiconductor layer in a second direction that is perpendicular to the first direction; and at least one voltage source configured to individually apply a voltage signal between the first semiconductor layer and the second semiconductor layer of each of the plurality of modulation elements.

DETAILED DESCRIPTION

Hereinafter, example embodiments will be described with reference to the accompanying drawings. The example embodiments described herein are for illustrative purposes only, and various modifications may be made therein. In the drawings, like reference numerals refer to like elements, and the sizes of elements may be exaggerated for clarity of illustration.

In the following description, when an element is referred to as being “above” or “on” another element, it may be directly on the other element while making contact with the other element or may be above the other element without making contact with the other element.

Although the terms “first” and “second” are used to describe various elements, these terms are only used to distinguish one element from another element. These terms do not limit elements to having different materials or structures.

In the present disclosure, terms such as “unit” or “module” may be used to denote a unit that has at least one function or operation and is implemented with hardware, software, or a combination of hardware and software.

An element referred to with the definite article or a demonstrative pronoun may be construed as the element or the elements even though it has a singular form.

Operations of a method may be performed in appropriate order unless explicitly described in terms of order or described to the contrary. In addition, examples or exemplary terms (for example, “such as” and “etc.”) are used for the purpose of description and are not intended to limit the scope of the present disclosure unless defined by the claims.

FIG. 1is a perspective view schematically illustrating a light modulating device100according to an example embodiment.FIG. 2A to 2Care views schematically illustrating the concept of guided mode resonance according to an example embodiment.

The light modulating device100is configured to modulate incident light while controlling the degree of light modulation, and includes an active layer120having a refractive index variable according to an electric field applied thereto. The active layer120may include a semiconductor material having a quantum well structure. A first semiconductor layer110and a second semiconductor layer130may be arranged below and above the active layer120, respectively.

The light modulating device100may include a voltage applying unit V (e.g., a voltage source or a power supply) configured to form an electric field in the active layer120. That is, voltage may be applied between the first semiconductor layer110and the second semiconductor layer130, and then the optical properties of the active layer120such as the refractive index of the active layer120may be varied according to an electric field formed in the active layer120by the voltage. The degree of incident light modulation may be varied according to variations in the refractive index of the active layer120. The light modulating device100may further include a processor (e.g., a processor1500) that generates and transmits a voltage control signal to the voltage applying unit V, and the voltage applying unit V may output an electrical signal having a certain voltage value as commanded by the voltage control signal.

The active layer120includes a material of which the refractive index varies with an electric field. A material, which has a low absorption coefficient in the wavelength band of light to be modulated and has a refractive index varying within a preset operation range according to an electric field applied thereto, may be used as a material of the active layer120.

The active layer120may include a Group III-V compound semiconductor. The active layer120may have a multiple quantum well structure based on InGaAsP/InP, GaAs/I nGaAs, or GaN/AIGaN.

The first semiconductor layer110and the second semiconductor layer130may include a Group III-V compound semiconductor. The first semiconductor layer110and the second semiconductor layer130may be doped with an N-type or P-type dopant. For example, the first semiconductor layer110may be doped with an N-type dopant, and the second semiconductor layer130may be doped with a P-type dopant.

The second semiconductor layer130has a shape in which a grating pattern135for guided mode resonance is formed. The grating pattern135may include gratings135aextending in a first direction (X direction) and repeatedly arranged in a second direction (Y direction), and a guided mode may be implemented in the second direction by the grating pattern135. The pitch (p) and depth (d) of the grating pattern135may be less than the operation wavelength of the light modulating device100, that is, the center wavelength λ0of the wavelength band of light to be modulated by the light modulating device100.

Based on that the light modulating device100has a reflectance peak for light having a particular wavelength satisfying conditions for guided mode resonance, a material for controlling the modulation range of light having the particular wavelength may be selected as the material of the active layer120to obtain high light modulation efficiency.

FIG. 2Aillustrates an example grating structure1of the second semiconductor layer130for describing a guided mode under the assumption that the example grating structure has an infinite grating length in a Z direction and an infinite grating arrangement in an X direction.

FIG. 2Billustrates the path of light incident on the grating structure1. Light (i) incident on the grating structure1is expressed as transmission light T, reflection light R, and internal travel light G, according to transmission and reflection modes in the grating structure1. The reflection light R is denoted as reflection light R0,0which is directly reflected by the surface of the grating structure1and reflection lights R0,1, R0,2, . . . which are reflected at least once by the inner surface of the grating structure1; the transmission light T is denoted as direct transmission light T0.0and transmission lights T0,1, T0,2, . . . which pass through the grating structure1after being reflected at least once by the inner surface of the grating structure1; and the internal travel light G is denoted as internal travel lights G1,1, G1,2, . . . according to the number of reflections in the grating structure1. The modes, in which incident light (i) is split into transmission T, reflection light R, and internal travel light G, are determined according to the wavelength of the incident light (i), the angle of incidence θ′, the detailed shape of the grating structure1, the refractive index n2of the grating structure1, and the refractive indexes n1and n3of surroundings.

The grating structure1may be disposed between a substrate having the refractive index n3and a superstrate having the refractive index n1, wherein the refractive index n2of the grating structure1may be higher than the refractive indexes n1and n3of the superstrate and the substrate. The superstrate having the refractive index n1may correspond to air or a semiconductor layer, and the substrate having the refractive index n3inFIG. 2Bmay correspond to the active layer120inFIG. 1. The grating structure1may act as an antenna or an array of antennas.

Multiple modes of light reflected by the grating structure1may interfere with each other, and a reflectance peak may be present when constructive interference occurs.

FIG. 2Cis a graph illustrating the reflectance of the grating structure1and the phase of light with respect to the wavelength of the light. A reflectance peak is present at a resonance wavelength.

Unlike a reflectance dip of a general reflective resonance structure using a diffracted Bragg reflector (DBR) or a metal substrate, a reflectance peak is present at a resonance wavelength in guided mode resonance, and thus high modulation efficiency may be obtained when light is modulated in a wavelength band including a resonance wavelength.

FIGS. 2A to 2Care views conceptually illustrating ideal guided mode resonance, and the light modulating device100of the example embodiment implements a localized guided mode by using the grating pattern135having a finite size. That is, referring toFIG. 1, the width w1in the longitudinal direction (X direction) of the gratings135ais finite, and the width w2in the direction (Y direction) in which the gratings135aare repeatedly arranged is finite. In this case, the widths w1and w2may be determined to implement a guided mode in the Y direction. For example, the width w2may be about 2.5 μm or more for sufficient interference between multiple reflection modes of light. In addition, the ratio of w2/w1may be about10or more.

The first semiconductor layer110is shaped to have a protruding element110aof which lateral sides are aligned with lateral sides of the active layer120and the second semiconductor layer130. The shape of the first semiconductor layer110is an example, and the first semiconductor layer110may be shaped to be entirely aligned with the active layer120and the second semiconductor layer130. The thicknesses t1, t2, and t3of the protruding element110a,the active layer120, and the second semiconductor layer130may range from about 150 nm to about 2500 nm. However, the thicknesses t1, t2, and t3are not limited thereto.

FIG. 3Ais a graph illustrating a relationship between wavelength and the absorption coefficient of an example of an active layer material of the light modulating device100with respect to electric fields applied to the light modulating device100, according to an example embodiment, andFIG. 3Bis an enlarged view illustrating a portion ofFIG. 3A.

The graphs relate to InP multiple quantum wells. In a wavelength band less than about 1500 nm, the absorption coefficient is high at about 1000/cm or greater when an electric field of 5 kV/cm is applied, and thus this wavelength band is not used because the efficiency of modulation may decrease. However, in a wavelength band greater than about 1500 nm, the absorption coefficient is very low at about 200/cm or less even when an electric field of 100 kV/cm is applied. When an electric field of 100 kV/cm is applied at a wavelength of about 1530 nm, the absorption coefficient is about 110/cm, and when an electric field of less than 100 kV/cm is applied or the wavelength is greater than about 1530 nm, the absorption coefficient is less than about 100/cm.

FIG. 4is a graph illustrating a relationship between wavelength and an amount of change in a real number part of the refractive index of the InP multiple quantum wells at a wavelength of about 1550 nm for different electric fields applied to the InP multiple quantum wells. At a wavelength of about 1530 nm, the amount of change in the real number part of the refractive index may be varied by about 0.0015 by an electric field of 100 kV/cm. When the electric field is varied from 20 kV/cm to 100 kV/cm at a wavelength of 1550 nm, the amount of change in the real number part of the refractive index is varied by about 0.00125.

As described above, InP multiple quantum wells have a low absorption coefficient and a large refractive index variation in the wavelength band of about 1550 nm, for example, from about 1520 nm to about 1580 nm, and thus it may be understood that highly efficient light modulation is possible using an InP multiple quantum well structure.

FIG. 5is a computational simulation graph illustrating the reflectance of the light modulating device100and the phase of light with respect to the wavelength of the light, according to an example embodiment andFIG. 6is a computational simulation graph illustrating variations in reflectance and phase with respect to variations in the refractive index of the active layer120of the light modulating device100, according to an example embodiment.

Graphs show results of computational simulation when the first semiconductor layer110and the second semiconductor layer130are respectively N-type InP and P-type InP, the active layer120has an InP multiple quantum well structure, the thicknesses t1, t2, and t3shown inFIG. 1are respectively 1.9 μm, 0.5 μm, and 0.3 μm, and the pitch P and the depth D of the grating pattern135are 0.522 μm and 0.21 μm, respectively.

Referring toFIG. 5, a resonance wavelength is present at about 1.57 μm, and a reflectance peak is present at the resonance wavelength.

The graph ofFIG. 6shows variations in reflectance and phase with respect to variations in refractive index at the resonance wavelength shown inFIG. 5. When the refractive index varies by about 0.002, a phase variation of about 1.57 radians (about 90 degrees) may occur. In addition, the minimum reflectance is about 20% or greater while the phase varies.

These results show that highly efficient light modulation is possible using a material having a low absorption coefficient at the resonance wavelength as the active layer120, based on that the grating pattern135inducing guided mode resonance has a reflectance peak at the resonance wavelength.

FIGS. 7A and 7Bare cross-sectional views schematically illustrating a light modulating device200according to another example embodiment.

The light modulating device200includes a first semiconductor layer210, an active layer220, and a second semiconductor layer230having a grating pattern235. The active layer220and the second semiconductor layer230have a structure divided into a plurality of individually controllable modulation elements M. Each of the plurality of individually controllable modulation elements M, or a preset number of the plurality of individually controllable modulation elements M may correspond to one pixel.

The modulation elements M are arranged at predetermined intervals in an X direction. This structure may be obtained by forming a plurality of grooves GR having a predetermined depth in the sequential stack of the first semiconductor layer210, the active layer220, and the second semiconductor layer230on which the grating pattern235is formed. The grooves GR may be formed at regular intervals in the X direction. The grooves GR may extend to have the predetermined depth d in the first semiconductor layer210, that is, the first semiconductor layer210may be shaped to have a plurality of protruding elements210awhich protrude in a Z direction, and as shown inFIG. 7A, the first semiconductor layer210may support the modulation elements M in common. Lateral surfaces of the protruding elements210amay be aligned with lateral sides of the active layer220and the second semiconductor layer230. The thicknesses t1, t2, and t3of the protruding elements210a,the active layer220, and the second semiconductor layer230may set to 1.9 μm, 0.5 μm, and 0.3 μm, respectively.

The material and shape of each of the modulation elements M may be substantially the same as or similar to those of the light modulating device100described with reference toFIG. 1. That is, the materials of the first semiconductor layer210, the active layer220, and the third semiconductor layer230may be the same as the materials of the first semiconductor layer110, the active layer120, and the third semiconductor layer130described with reference toFIG. 1. The descriptions of the pitch and depth of the grating pattern135shown inFIG. 1, and the description of the relationship between the widths w1and w2of the grating pattern135in two directions may also be applied to the pitch, depth, and the relationship between widths in two directions of the grating pattern235.

In the light modulating device200, voltage may be individually applied to the second semiconductor layer230of each of the modulation elements M. The first semiconductor layer210may function as a common electrode for the second semiconductor layer230of each of the modulation element M. A common electric potential, which is a reference for a voltage applied to the second semiconductor layer230of each of the modulation element M, may be applied to the first semiconductor layer210. Different electric fields may be formed in the active layer120of the modulation elements M depending on voltages between the first semiconductor layer210and the second semiconductor layer230. The phase of incident light may be individually modulated by the modulation elements M.

The width of the grooves GR may be set by considering the pitch (A) of the modulation elements M which are configured to be individually controlled. The pitch (A) of the modulation elements M may be set by considering the resolution of phase modulation. The thickness t1of the protruding elements210aof the first semiconductor layer210, which are formed by the grooves GR, may be about 20 nm or more. The spacing between the protruding elements210a,that is, the width (s) of the grooves GR, may be within the range of about 50 nm to about 1500 nm or about 50 nm to 500 nm.

Because the light modulating device200includes the modulation elements M configured to individually modulate incident light within individually controllable ranges, the light modulating device200may have various types of optical performance. For example, the light modulating device200may have the function of a device such as a beam deflector that deflects light, a beam steerer that is capable of controlling the direction of light deflection, a beam shaper that changes the beam pattern of incident light, and a lens that condenses or expands light.

FIG. 8is a conceptual view illustrating the light modulating device200when the light modulating device200operates as a beam steering device according to an example embodiment.

Voltages may be applied to the modulation elements M such that a predetermined phase difference may occur between adjacent modulation elements M for outputting incident light Li as modulated light Lm which is deflected to at a predetermined angle. A voltage V1may be applied to a modulation element M_1to induce a phase modulation φ1, and a voltage V2may be applied to a modulation element M_2to induce a phase modulation φ2. Voltages V3and V4may be respectively applied to modulation elements M_3and M_4to induce phase modulations φ3and φ4. The phase modulations φ1to φ4may be monotonically increasing or decreasing values and may occur at regular intervals, that is, may occur as linear variations. However, the phase modulations φ1to φ4are not limited thereto. The modulation elements M may have a phase modulation pattern repeating with a predetermined period T. The deflection angle θ of light by this phase modulation may be expressed as follows.

where T refers to the period of the phase modulations φ1to φ4which are repeated in the light modulating device200, and A refers to the wavelength of incident light.

The number of modulation elements M included in one period T may be set by considering the pitch of the modulation elements M adjacent to each other, the amounts of phase modulation obtainable by modulation elements M, and an intended deflection angle θ.

In addition, because the amount of phase modulation by a modulation element M_k is adjustable according to a voltage applied to the modulation element M_k, the light modulating device200may be operated as a beam steering device.

The light modulating device200may further include a processor (e.g., a processor1500shown inFIG. 13) that controls voltages applied to the modulation elements M to deflect incident light at a predetermined angle. The processor may time-sequentially vary application voltages to time-sequentially vary the deflection angle θ of light, and thus, an area may be scanned with the light.

FIG. 9is a graph illustrating the intensity of light reflected by the light modulating device200with respect to angle, according to an example embodiment.

In an example embodiment, a voltage source may apply three different voltages (e.g., voltages V1, V2, and V3) to a first group of pixels, including a first pixel, a second pixel and a third pixel (e.g., modulation elements M_1, M_2, and M_3), so that the first pixel, the second pixel, and the third pixel have 0 degrees, 3.5 degrees, and 90 degrees of the deflection angle of the light, respectively, and have 0.22, 0.23, and 0.51 of reflectance. The voltage sources may apply the three different voltage to a second group, a third group, and a n-th group of pixels, in the manner in which the voltage source applies the voltages to the first group of pixels, wherein n denotes a natural number greater than three.

The graph shows results obtained when phase modulations by adjacent modulation elements M are respectively 0 degree, 3.5 degrees, and 90 degrees, and this phase modulation arrangement is periodically repeated. The graph shows two peaks at 0 degree and −32 degrees. The peak at −32 degrees corresponds to the deflection angle of light, that is, a main lobe. The peak at 0 degree corresponds to a side lobe. The contrast between the main lobe and the side lobe is a major performance factor of the beam steering device and may be expressed as a side mode suppression ratio (SMSR). The SMSR shown in the graph ofFIG. 9is about 5.75 dB which is a very high value compared to the SMSRs of devices of the related art.

FIGS. 10A and 10Bare cross-sectional views schematically illustrating a light modulating device300according to another example embodiment.

The light modulating device300of the current example embodiment has a structure in which modulation elements M are two-dimensionally arranged in X and Y directions. This structure may be obtained by forming a plurality of grooves GR having a predetermined depth in the sequential stack of a first semiconductor layer310, an active layer320, and a second semiconductor layer330on which a grating pattern335is formed. The grooves GR may be formed at regular intervals in the X and Y directions. The width s1of the grooves GR in the X direction and the width s2of the grooves Gr in the Y direction may be different from each other.

The pitch (first pitch A1) of the modulation elements M in the X direction and the pitch (second pitch A2) of the modulation elements M in the Y direction may be different from each other. The reason for this is that a certain number of gratings335ais required for a localized guided mode. The ratio A2/A1of the second pitch A2to the first pitch Al may be about 2.5 or more.

Optical performance may be obtained in more various types owing to the modulation elements Ms which are two-dimensionally arranged. For example, when the light modulating device300is used as a beam deflector or a beam steerer, the angle of light may be two-dimensionally adjusted.

FIGS. 11 and 12are conceptual views illustrating beam steering devices500and600to which light modulating devices are applied according to example embodiments.

FIG. 11illustrates the beam steering device500as an example. Referring toFIG. 11, a beam may be one-dimensionally steered using the beam steering device500. That is, a beam may be directed toward an object OBJ while being steered in a first direction D1. The light modulating device200including the modulation elements M which are one-dimensionally arranged may be used as the beam steering device500.

FIG. 12illustrates the beam steering device600as another example. Referring toFIG. 12, a beam may be two-dimensionally steered using the beam steering device600. That is, a beam may be directed toward an object OBJ while being steered in a first direction D1and a second direction D2perpendicular to the first direction D1. The light modulating device300including the modulation elements M which are two-dimensionally arranged may be used as the beam steering device600. The beam steering device600may have different two-dimensional control ranges. That is, as described with reference toFIGS. 10A and 10B, in the light modulating device300, the pitch of the modulation elements M in the longitudinal direction (X direction) of the gratings335amay be different from the pitch of the modulation elements M in a direction (Y direction or guided mode direction) perpendicular to the longitudinal direction of the gratings335a,and the control range in one of the first and second directions D1and D2which corresponds to the length direction of the gratings335amay be greater than the control range in the other of the first and second directions D1and D2.

FIG. 13is a block diagram schematically illustrating an electronic apparatus1000according to an example embodiment.

Referring toFIG. 13, the electronic apparatus1000may include: a light emitting device (e.g., a laser)1300configured to emit light toward an object OBJ; a photodetector1700configured to receive light reflected from the object OBJ; and a processor1500configured to perform an operation for acquiring information on the object OBJ from the light received by the photodetector1700. The electronic apparatus1000may also include a memory1900that stores codes or data for operating the processor1500.

The light emitting device1300may include a light source1100and a beam steering device1200. The light source1100may generate source light for scanning the object OBJ. The source light may be pulsed laser light. The beam steering device1200is configured to illuminate the object OBJ by changing the propagation direction of light emitted from the light source1100, and may include one of the light modulating devices100,200and300. The beam steering device1200may correspond to the beam steering device500or600illustrated inFIGS. 11 and 12.

Additional optical devices may be arranged between the light emitting device1300and the object OBJ to adjust the direction of light emitted from the light emitting device1300toward the object OBJ or additionally modulate light emitted from the light emitting device1300.

The photodetector1700senses light Lr reflected from the object OBJ. The photodetector1700may include an array of photo detection elements. The photodetector1700may further include a spectroscopic device configured to analyze light Lr reflected from the object OBJ according to the wavelength of the light Lr.

The processor1500may perform an operation for obtaining information on the object OBJ from the light Lr received by the photodetector1700. In addition, the processor1500may perform or manage overall processing and control operations of the electronic apparatus1000. The processor1500may acquire and process information on the object OBJ. For example, the processor1500may acquire and process two-dimensional (2D) or three-dimensional (3D) image information. In addition, the processor1500may generally control operations such as the operation of the light source1100of the light emitting device1300or the operation of the photodetector1700. In addition, the processor1500may authenticate a user or the like based on information obtained from the object OBJ, and may also execute other applications.

The memory1900may store codes to be executed on the processor1500. In addition, the memory1900may store various execution modules to be executed on the electronic apparatus1000and data for the execution modules. For example, the memory1900may store: program codes to be executed on the processor1500for obtaining information on the object OBJ; and codes such as application modules to be executed on the processor1500using the information on the object OBJ. In addition, the memory1900may also store a program such as a communication module, a camera module, a video playback module, or an audio playback module for operating a device that may be additionally included in the electronic apparatus1000.

Results of calculation of the processor1500, that is, information on the shape and location of the object OBJ, may be transmitted to other devices or units if needed. For example, information on the object OBJ may be transmitted to a control unit of another electronic apparatus that uses the information on the object OBJ. Examples of the other devices or units to which the results of calculation are transmitted may include display devices and printers which are configured to output the results. In addition, examples of the other devices or units may include smartphones, personal digital assistants (PDAs), laptop computers, personal computer (PCs), various wearable devices, and other mobile or non-mobile computing devices, but are not limited thereto.

Examples of the memory1900may include a flash memory, a hard disk, a multimedia micro card, a card-type memory (for example, an SD or XD memory), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, and an optical disk.

The light emitting device1300, the processor1500, the photodetector1700, and the memory1900may be wired or wirelessly connected to each other, and the illustrated structure of the electronic apparatus1000may be variously modified.

Examples of the electronic apparatus1000may include portable mobile communication devices, smartphones, smartwatches, personal digital assistants (PDAs), laptop computers, PCs, and other mobile or non-mobile computing devices, but are not limited thereto. In addition, examples of the electronic apparatus1000may include autonomous driving devices such as unmanned vehicles, autonomous vehicles, robots, or drones, and Internet of Things (IoT) devices.

The beam steering device1200provided in the electronic apparatus1000may include a light modulating device having high modulation efficiency and may thus scan the object OBJ with light having a low ratio of side lobe to main lobe. In addition, because the beam steering device has a structure basically not requiring mechanical movement, the beam steering device may be operated at a high speed. Therefore, the electronic apparatus1000may acquire and process information on the object OBJ with high precision and high speed.

FIGS. 14 and 15are a side view and a plan view that conceptually illustrate a LiDAR apparatus1001applied to a vehicle50according to an example embodiment.

Referring toFIG. 14, the LiDAR apparatus1001may be applied to the vehicle50to acquire information on an object60. The LiDAR apparatus1001is an example of the electronic apparatus1000illustrated inFIG. 13and may use a phase-shift method or a time-of-flight (TOF) method to obtain information on the object60. The vehicle50may have an autonomous driving function. The LiDAR apparatus1001may detect objects or people such as the object60which are at positions in the travel direction of the vehicle50. In addition, the distance to the object60may be measured using information such as a time difference between a transmission signal and a detection signal. In addition, as illustrated inFIG. 15, information on a nearby object61and a distant object62may be obtained within a scanning range.

FIGS. 14 and 15illustrate the case in which the LiDAR apparatus1001is applied to the vehicle50. However, example embodiments are not limited thereto. The LiDAR apparatus1001may be applied to devices such as flying objects (for example, drones), mobile devices, small vehicles or walking assistance devices (for example, bicycles, motorcycles, strollers, or boards), robots, human/animal-assistance devices (for example, canes, helmets, accessories, clothes, watches, or bags), Internet of Things (IoT) devices/systems, or security devices/systems.

The light modulating devices of the example embodiments are applicable to various optical devices in addition to being applicable to LiDAR apparatuses. For example, three-dimensional information on a space or an object may be obtained by scanning with the light modulating devices of the example embodiments, and thus the light modulating devices of the example embodiments may be applied to three-dimensional image acquisition devices or three-dimensional cameras. In addition, the light modulating devices may be applied to holographic display devices or structured light generating devices. In addition, the light modulating devices may be applied to various optical devices such as beam scanning devices, hologram generating devices, optical coupling devices, variable focus lenses, depth sensors, etc.

As described above, according to the one or more of the above example embodiments, in the light modulating devices, a quantum well structure having a low absorption coefficient is employed in a material having a variable refractive index, and a grating pattern is used for implementing guided mode resonance. Therefore, the light modulating devices may have high modulation efficiency.

The light modulating devices may be employed in various electronic apparatuses such as beam steering apparatuses or LiDAR apparatuses.