A diamond Raman laser may include a diamond Raman oscillator (DRO) with a first diamond gain medium, a seed laser providing a seed beam at a seed wavelength, and a cavity configured to resonate at a first-Stokes wavelength, the first-Stokes wavelength corresponding to first-Stokes emission in diamond when pumped with the seed wavelength, and where the DRO outputs a first-Stokes beam at the first-Stokes wavelength. The diamond Raman laser may further include a diamond Raman amplifier (DRA) to amplify the first-Stokes beam and generate an amplified first-Stokes beam, where the DRA includes two or more diamond Raman amplification stages, each including one or more second diamond gain media, and one or more optical filters to filter light with a second-Stokes wavelength generated in at least one of the one or more second gain media.

TECHNICAL FIELD

The present disclosure relates generally to amplified laser systems and, more particularly, to amplified Raman laser systems with diamond gain media.

BACKGROUND

While almost all high brightness laser development for the last few decades has been around 1 μm, many civil and defense applications such as material processing, atmospheric measurements, laser radar, laser rangefinders, and free-space optical communications are more suited to longer wavelengths. Lasers above 1.4 μm specifically benefit from high transmission in atmosphere and low eye-exposure risks, making them critical for any remote applications where bystanders may be involved. Erbium and direct diode lasers access these wavelengths, but have not achieved sufficiently high power for most of the aforementioned applications. Optical Parametric Oscillators (OPOs) have been shown to access these wavelengths with greater brightness and energy, however, they are impractically complex and costly for most commercial applications. There is therefore a need to develop systems and methods to cure the above deficiencies.

SUMMARY

A diamond Raman laser is disclosed in accordance with one or more illustrative embodiments of the present disclosure. In one illustrative embodiment, the diamond Raman laser includes a diamond Raman oscillator (DRO). In another illustrative embodiment, the DRO includes a first diamond gain medium. In another illustrative embodiment, the DRO includes a seed laser providing a seed beam at a seed wavelength. In another illustrative embodiment, the DRO includes a cavity that resonates at a first-Stokes wavelength, where the first-Stokes wavelength corresponds to first-Stokes emission in diamond when pumped with the seed wavelength, and where the diamond Raman oscillator outputs a first-Stokes beam at the first-Stokes wavelength. In another illustrative embodiment, the diamond Raman laser includes a diamond Raman amplifier (DRA) to amplify the first-Stokes beam and generate an amplified first-Stokes beam through stimulated Raman scattering. In another illustrative embodiment, the DRA includes one or more pump lasers to generate pump light at the seed wavelength. In another illustrative embodiment, the DRA includes two or more diamond Raman amplification stages, each including one or more second diamond gain media, where the first-Stokes beam and at least a portion of the pump light propagates colinearly through the two or more diamond Raman amplification stages. In another illustrative embodiment, the DRA includes one or more optical filters to filter light with a second-Stokes wavelength generated in at least one of the one or more second gain media, where the second-Stokes wavelength corresponds to second-Stokes emission in diamond when pumped with the first-Stokes wavelength.

A diamond Raman amplifier (DRA) is disclosed in accordance with one or more illustrative embodiments of the present disclosure. In one illustrative embodiment, the DRA includes one or more pump lasers to generate pump light at the seed wavelength. In another illustrative embodiment, the DRA includes two or more diamond Raman amplification stages to receive an input beam with an input wavelength and generate an amplified beam through stimulated Raman scattering, where each of the two or more diamond Raman amplification stages include one or more diamond gain media, and where the input beam and at least a portion of the pump light propagates colinearly through the two or more diamond Raman amplification stages. In another illustrative embodiment, the DRA includes one or more optical filters to filter light with a second-Stokes wavelength generated in at least one of the one or more diamond gain media, where the second-Stokes wavelength corresponds to Stokes emission in diamond when pumped with the first-Stokes wavelength.

A method is disclosed in accordance with one or more illustrative embodiments of the present disclosure. In one illustrative embodiment, the method includes generating a seed beam at a seed wavelength. In another illustrative embodiment, the method includes pumping a diamond Raman oscillator including a first diamond gain medium with the seed laser to generate a first-Stokes beam with a first-Stokes wavelength, where the first-Stokes wavelength corresponds to first-Stokes emission in diamond when pumped with the seed wavelength. In another illustrative embodiment, the method includes amplifying the first-Stokes beam with a diamond Raman amplifier (DRA). In another illustrative embodiment, the DRA includes one or more pump lasers to generate pump light at the seed wavelength. In another illustrative embodiment, the DRA includes two or more diamond Raman amplification stages, each including one or more second diamond gain media, where the first-Stokes beam and at least a portion of the pump light propagates colinearly through the two or more diamond Raman amplification stages. In another illustrative embodiment, the method includes filtering light with a second-Stokes wavelength generated in at least one of the one or more second gain media with one or more optical filters located in the DRA, where the second-Stokes wavelength corresponds to second-Stokes emission in diamond when pumped with the first-Stokes wavelength.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to systems and methods for generating amplified laser light using a diamond Raman master oscillator power amplifier (e.g., a DR-MOPA) architecture. In some embodiments, a DR-MOPA includes a diamond Raman oscillator (DRO) pumped at a seed wavelength to generate a first-Stokes beam at a first-Stokes wavelength corresponding to first-Stokes emission in diamond in response to the seed wavelength, a diamond Raman amplifier (DRA), two or more diamond Raman amplification stages (DRA stages) to amplify the first-Stokes beam, and one or more optical filters (e.g., between the two or more DRA stages) to suppress a second-Stokes wavelength (e.g., corresponding to second-Stokes emission in diamond in response to the seed wavelength) during the amplification of the first-Stokes beam. In this way, pump suppression by second-Stokes emission may be mitigated to enable high-power amplification of the first-Stokes beam. Some embodiments further include a diamond Raman converter (DRC) to convert the amplified first-Stokes beam to a second-Stokes beam at the second-Stokes wavelength. In this way, the high-power laser light at the second-Stokes wavelength may be efficiently generated.

Diamond Raman lasers (DRLs) provide an efficient and feasible alternative to OPOs to achieve wavelengths above 1.4 μm owing to simple laser designs, automatic phase-matching conditions, and diamond's exceptional optical and thermal properties. Also, as the thermal conductivity of diamond is the highest of any bulk material, such lasers are very resistant to thermal lensing.

DRLs in general do not require rare-earth doping. Rather, DRLs function by Raman-shifting a pump signal (such as, but not limited to, a high energy Nd:YAG laser) to longer wavelengths in a diamond medium. In this way, the emission is based on a non-linear effect in which pump light excites vibrational modes of the atomic structure or crystal lattice, where the wavelength of the output light is related to a difference between the wavelength of the pump light and that of the vibrational modes and gain is proportional to the intensity of the first-Stokes signal and the pump. The output wavelength is known as a first-Stokes wavelength. Further, this effect may be cascaded to achieve second-Stokes wavelengths and beyond.

It is contemplated herein that the generation of second-Stokes wavelengths (or higher order Stokes wavelengths) provides substantial flexibility for the generation of long wavelengths with DRLs, but also limits the achievable output power. In particular, such wavelengths saturate pump depletion. DRL designs have thus been limited to a relatively narrow range of input intensities and have had low potential for scalability.

It is further contemplated herein that high-power amplification of first-Stokes wavelengths may be achieved using multiple amplification stages with optical filters for second-Stokes suppression. Accordingly, embodiments of the present disclosure are directed to a DR-MOPA providing amplification of a first-Stokes beam at a first-Stokes wavelength (e.g., generated with a DRO) with two or more DRAs with optical filters in or between the DRAs providing filtering of second-Stokes light. In this configuration, the relative powers (or energy densities) of the first-Stokes beam during amplification and any generated second-Stokes beams (or higher-order Stokes beams) may be controlled to provide efficient amplification of the first-Stokes beam. For example, the amplification in any particular DRA may be managed to limit undesirable effects of second-Stokes emission in that DRA and the optical filters may then remove (or at least substantially filter) the second-Stokes wavelengths prior to a successive DRA.

Additionally, the multi-stage amplifier configuration disclosed herein facilitates efficient management of thermal effects in the DRAs. Although Raman beam cleanup effects in Raman crystals may efficiently transfer energy from highly divergent (high M2) pump beams into diffraction-limited Raman beams, the thermal effects in the material can nonetheless pose a challenge in achieving high output beam-quality. However, the multi-stage amplifier configuration disclosed herein may distribute the thermal load across multiple DRAs such that thermal management requirements on any particular DRA may be reduced (e.g., relative to a single-stage configuration) and further retain good output beam quality. As a result, this multi-stage amplifier configuration may provide a linearly scalable approach for the generation of a high-power first-Stokes beam, which is limited only by damage thresholds of associated optical elements.

In some embodiments, a DR-MOPA further includes one or more DRCs to convert the first-Stokes beam into a second-Stokes beam. For example, a DRC may transfer energy in a first-Stokes beam at a first-Stokes wavelength to a second-Stokes beam at a second-Stokes wavelength. Additional diamond Raman converters may also be utilized to provide energy at higher-order Stokes wavelengths. When combined with multi-stage amplification of a first-Stokes beam with optical filters for suppression of second-Stokes light (or higher-order Stokes light), a DR-MOPA as disclosed herein may generate high-energy beams at any desired Stokes wavelength.

Further, since Stokes wavelengths (e.g., first-Stokes wavelengths, second-Stokes wavelengths, third Stokes wavelengths, or the like) are associated with Raman shifts of an incident seed beam, the output of a DR-MOPA may generally be tuned to a wide range of wavelengths by tuning or otherwise controlling the wavelength of the seed beam. As a non-limiting illustration, a DR-MOPA as disclosed herein may provide an amplified second-Stokes beam at 1485 nm using a seed wavelength of 1064 nm (e.g., generated by a Nd:YAG laser). In this configuration, the DRO may generate a first-Stokes beam at 1239 nm, which is amplified by two or more DRAs and then converted to a second-Stokes beam at 1485 nm using a DRC.

A DR-MOPA as disclosed herein may also be flexibly designed to provide output pulses at a range of pulse energies and repetition rates. For example, such a system may be capable of generating 10s-100s of mJ-level nanosecond laser pulses at the second-Stokes wavelength (e.g., 1485 nm) at kHz repetition rates using conventional commercial off-the-shelf (COTS) diode-pumped 1064 nm Nd:YAG solid-state lasers.

Referring now toFIGS. 1-4, systems and methods for generating amplified laser light are described in greater detail in accordance with one or more embodiments of the present disclosure.

FIG. 1is a conceptual view of a DR-MOPA100, in accordance with one or more embodiments of the present disclosure. In one embodiment, a DR-MOPA100includes a diamond Raman oscillator (DRO)102to receive a seed beam104at a seed wavelength from a seed laser106and generate a first-Stokes beam108at a first-Stokes wavelength in response to the seed beam104.

The DRO102may have any oscillator design suitable for generating the first-Stokes beam108from the seed beam104. For example, the DRO102may include a diamond gain medium and a laser cavity designed to resonate at the first-Stokes wavelength. In this configuration, the seed beam104may propagate through the diamond gain medium to generate light having the first-Stokes wavelength through Raman scattering which is recirculated through the diamond gain medium by cavity mirrors to build up energy within the laser cavity through stimulated Raman scattering. The first-Stokes beam108may then exit the DRO102through one of the cavity mirrors (e.g., operating as an output coupler).

The seed laser106may include any laser design suitable for generating a seed beam104suitable for inducing Raman scattering in the diamond gain medium of the DRO102. For example, the seed wavelength of the seed laser106may include any wavelength transparent to diamond and may thus include wavelengths in the range of approximately 230 nm to 100 microns. Further, the first-Stokes wavelength of the first-Stokes beam108will be shifted from the seed wavelength by the Raman shift of diamond, which is approximately 40 THz based on the chemistry of diamond. As a result, the first-Stokes beam108may be tuned to any wavelength transparent to diamond by tuning or otherwise controlling the wavelength of the seed beam104(e.g., the seed wavelength).

The seed laser106may further operate with any temporal profile. In one embodiment, the seed laser106operates as a continuous-wave (CW) laser to generate a CW first-Stokes beam108. In another embodiment, the seed laser106operates as a pulsed laser to generate a pulsed first-Stokes beam108. For example, the first-Stokes beam108may generally include pulses on the order of femtosecond, picoseconds, nanosecond, or longer based on the properties of the seed laser106and the design of the DRO102.

Additionally, the seed laser106and/or the DRO102may be implemented using any laser technology known in the art such as, but not limited to, solid-state or fiber laser technology.

As an illustrative example, the seed laser106may include a Nd:YAG laser operating at 1064 nm, which provides first-Stokes emission at 1239 nm, where the Nd:YAG pump lasers may be based on any laser technology such as, but not limited to, COTS diode-pumped technology. For instance, the seed laser may include a COTS narrow-bandwidth high rep-rate short pulse 10 ns Nd:YAG laser, a custom-built high repetition rate diode-pumped solid-state laser (DPSSL) system with a variable pulse duration (e.g., in the range of 1-40 ns), or any suitable system.

In some embodiments, a DR-MOPA100includes at least one multi-stage diamond Raman amplifier (DRA)110with two or more diamond Raman amplification stages (DRA stages)112to amplify the first-Stokes beam108. For example,FIG. 1illustrates a DRA110including DRA stages112-1through112-N. The DRA110may further include one or more pump lasers114to pump the two or more DRA stages112, where the one or more pump lasers114may provide pump light having the same wavelength as the seed laser106(e.g., the seed wavelength).

In one embodiment, a DRA stage112includes one or more diamond gain media pumped by one or more pump lasers114to amplify the first-Stokes beam108through stimulated Raman scattering. For example, the first-Stokes beam108from the DRO102may be aligned coaxially with pump light in the diamond to provide amplification through stimulated Raman scattering. The desired pulse characteristics for the pump lasers114may be determined by the characteristics of the DRO102to promote efficient amplification of the first-Stokes beam108from the DRO102. However, it is contemplated herein that the beam quality of the pump lasers114does not need to be the same as, and may be significantly worse than, the beam quality of the first-Stokes beam108from the DRO102. This is due to the Raman effect in the diamond crystal, where the energy from the pump lasers114may be channeled to the first-Stokes beam108through phonon interactions. As a result, a DRA110may be implemented with relatively lower-cost and/or compact pump lasers114while maintaining desired beam profile characteristics in the amplified first-Stokes beam108.

A DRA stage112may have any suitable design suitable for amplifying the first-Stokes beam108. Further, a DRA110may generally include any selected number of DRA stages112having the same or different designs. In this way, the gain characteristics of each DRA110may be tailored to provide highly-controlled gain, thermal management, beam profile characteristics of the amplified first-Stokes beam108, and/or use of pump power from the pump lasers114through the entire DRA110. For example, a particular DRA stage112may include a single diamond gain medium or multiple diamond gain media depending on the amount of gain desired for the particular stage. Further, any number of pump lasers114may be utilized to pump any number of DRA stages112. For instance, a single pump laser114may pump one or more DRA stages112. By way of another example, pump beams from two or more pump lasers114may be combined to pump one or more DRA stages112. In this way, the first-Stokes beam108may be amplified to powers (or energy densities) well beyond the amplification provided by any given pump laser114. By way of another example, any particular DRA stage112may provide single-pass or multi-pass operation.

It is contemplated herein that light with the first-Stokes wavelength generated in the DRO102or any of the DRA stages112may induce Raman scattering at a second-Stokes wavelength. Further, this process may generally cascade to provide higher-order Stokes wavelengths. For example, some of the power of the first-Stokes beam108may go into the formation of a second-Stokes beam, which may reduce the otherwise available power of the first-Stokes beam108. This second-Stokes beam may then be amplified in a diamond gain medium through stimulated Raman scattering using additional energy from the first-Stokes beam108in much the same way that the first-Stokes beam108itself is amplified using energy from the pump lasers114. As a result, the generation of light at second-Stokes wavelengths (or higher-order wavelengths) may limit or otherwise diminish the formation of a high-power first-Stokes beam108.

In some embodiments, a DR-MOPA100includes one or more optical filters116in the DRA110to pass the first-Stokes wavelength and reject the second-Stokes wavelength and/or higher-order Stokes wavelengths. The optical filters116may generally be located at any suitable location within the DRA110such as, but not limited to, prior to, after, or within any of the DRA stages112. In this way, the power, intensity, or energy density of light with the second-Stokes wavelength (or higher-order Stokes wavelengths) may be suppressed or otherwise limited within the DRA110to facilitate increased amplification of the first-Stokes beam108. For example, various aspects of any particular DRA stage112such as, but not limited to, the gain, the length of a diamond gain medium, or a number of diamond gain media may be tailored to amplify the first-Stokes beam108while keeping the power in the second-Stokes wavelength at or below a selected threshold. Then, optical filters116may reject the second-Stokes wavelengths prior to a subsequent DRA stage112. It is contemplated herein that such a multi-stage amplification approach with optical filters116may enable the formation of a first-Stokes beam108with a substantially higher power than possible using traditional techniques. In a general sense, any number of DRA stages112and optical filters116may be used to provide highly-controlled amplification to any desired power, intensity, or energy density. In some cases, the amount of amplification possible is limited only by material damage thresholds of constituent optics.

The optical filters116may include any type of filters known in the art such as, but not limited to, thin-film filters (e.g., dielectric filters) or metallic filters. Further, an optical filter116may pass first-Stokes wavelengths through transmission or reflection, and may reject second-Stokes wavelengths (or higher-order Stokes wavelengths) through any combination of transmission, reflection, or absorption.

FIG. 2is a schematic view of a DR-MOPA100including optical filters116operating as second-Stokes filters and as pump coupling mirrors for DRA stages112(e.g., any of DRA stages112-1,112-2,112-3), in accordance with one or more embodiments of the present disclosure. For example, the optical filters116may operate as wavelength multiplexers to combine the first-Stokes beam108with pump light from the pump lasers114and further to divert second-Stokes wavelengths from the optical path of the first-Stokes beam108prior to the DRA stages112. As illustrated inFIG. 2, a first-Stokes beam108from the DRO102or any prior DRA stage112may include first-Stokes wavelengths118and second-Stokes wavelengths120, and an optical filter116may pass the first-Stokes wavelengths118and reject the second-Stokes wavelengths120. For instance, the DRA110may then include one or more beam blocks122or other elements to absorb or otherwise manage the rejected second-Stokes wavelengths120. The optical filter116may further combine the passed first-Stokes wavelengths118with pump light124from a pump laser114for amplification of the first-Stokes wavelengths118by a DRA stage112. However, it is to be understood thatFIG. 2and the associated description is provided solely for illustrative purposes and should not be interpreted as limiting. For example, the optical filters116may be provided as separate components and need not be combined on a common substrate with pump-coupling optics.

In some embodiments, a DR-MOPA100includes an optical pre-amplifier126to amplify the seed beam104to a desired level prior to entering the DRO102. In this way, the gain requirements on the DRA110required to generate a first-Stokes beam108with a certain power may be reduced or otherwise controlled. The optical pre-amplifier126may include any type of optical pre-amplifier known in the art suitable for amplifying the seed beam104by a selected amount. For example, the optical pre-amplifier126may include, but is not limited to, a diode-pumped Yb-fiber pre-amplifier.

In some embodiments, a DR-MOPA100includes one or more Diamond Raman Converters (DRCs)128to convert the amplified first-Stokes beam108from the DRA110to a second-Stokes beam130at a second-Stokes wavelength or a higher-order Stokes wavelength.

FIG. 3is a schematic view of the DR-MOPA100ofFIG. 1further including a DRC128, in accordance with one or more embodiments of the present disclosure. For example, a DRC128may include one or more diamond gain media, where the amplified first-Stokes beam108from the DRA110is colinearly propagated with light at the second-Stokes wavelength through the diamond to induce a transfer of energy from the first-Stokes wavelength to the second-Stokes wavelength. In particular, the second-Stokes wavelength may be shifted from the first-Stokes wavelength by the Raman shift of diamond (e.g., 40 THz) in a manner similar to the generation of the first-Stokes wavelength from the seed wavelength.

The light at the second-Stokes wavelength may be provided as a separate beam (e.g., with a dedicated laser source) or may already be present in the amplified beam from the DRA110. For example, in a configuration with a DRC128, residual second-Stokes emission generated in a final DRA stage112may not be suppressed with optical filters116prior to entering the DRC128and may thus operate as a seed for stimulated Raman scattering at the second-Stokes wavelength in the DRC128. By way of another example, residual pump light from a pump laser114(e.g., from a previous DRA stage112or other any other source) may be used to seed an additional DRO designed to resonate at the second-Stokes wavelength and generate a second-Stokes beam used to initiate or otherwise seed the conversion process in the DRC128. By way of another example, residual second-Stokes emission deflected from the optical path of the first-Stokes beam108in the DRA110by the optical filters116may be combined and utilized as a seed for the DRC128.

It is contemplated herein that a DRC128to generate a second-Stokes beam130based on an amplified first-Stokes beam108from a DRA110as disclosed herein may provide an additional pathway for the generation of high-power beams using Raman amplification processes. For example, although the wavelength of the first-Stokes beam108may generally be tuned by controlling the seed wavelength, it may be impractical or undesirable in some applications to provide a seed laser106and pump lasers114at a wavelength required to directly generate a first-Stokes beam108at a desired output wavelength.

As an illustration and continuing the non-example above, a second-Stokes beam130at a second-Stokes wavelength of 1485 nm may be generated using a seed laser106and pump lasers114with wavelengths at 1064 nm (e.g., using mature Nd:YAG technology) to provide a first-Stokes beam108with a wavelength of 1239 nm and a DRC128to generate the second-Stokes beam130at 1485 nm. In this way, the DR-MOPA100may be driven by cost-effective, compact, and robust Nd:YAG technology. It is to be understood, however, that these principles may be applied to provide a second-Stokes beam130at any desired wavelength using any selected seed wavelengths.

It is further contemplated herein that a DRC128may have any design suitable for generating a second-Stokes beam130from a first-Stokes beam108. For example, the DRC128may include any number of conversion stages (e.g., pumped with additional light sources at the second-Stokes wavelength) and/or any number of diamond gain media in any stage.

Additionally, the DR-MOPA100may include any number of cascaded DRCs128to provide output at higher-order Stokes wavelengths. For example, the DR-MOPA100may include an additional DRC128to transfer energy from the second-Stokes beam130to a third Stokes beam having a third Stokes wavelength.

FIG. 4is a flow diagram illustrating steps performed in a method400amplifying laser light with Raman amplification, in accordance with one or more embodiments of the present disclosure. Applicant notes that the embodiments and enabling technologies described previously herein in the context of the DR-MOPA100should be interpreted to extend to the method400. It is further noted, however, that the method400is not limited to the architecture of the DR-MOPA100.

In one embodiment, the method400includes a step402of generating a seed beam at a seed wavelength. In another embodiment, the method400includes a step404of pumping a diamond Raman oscillator including a first diamond gain medium with the seed laser to generate a first-Stokes beam with a first-Stokes wavelength. For example, the first-Stokes wavelength may correspond to first-Stokes emission in diamond when pumped with the seed wavelength. In this way, the first-Stokes beam may have any wavelength suitable for inducing Raman scattering in diamond, which may generally include any wavelength in a transmission window of diamond. For example, the first-Stokes beam may have a wavelength in the range of 230 nm to 100 microns.

In another embodiment, the method400includes a step406of amplifying the first-Stokes beam with a diamond Raman amplifier (DRA) including two or more diamond Raman amplification stages. For example, the two or more diamond Raman amplification stages may be pumped using pump light at the seed wavelength and may amplify the first-Stokes beam through stimulated Raman scattering. Further, the two or more diamond Raman amplification stages may have any design suitable for amplifying the first-Stokes beam such as, but not limited to, single-pass or multi-pass designs.

In another embodiment, the method400includes a step408of filtering light with a second-Stokes wavelength in the DRA, where the second-Stokes wavelength may correspond to second-Stokes emission in diamond when pumped with the first-Stokes wavelength. For example, the step408may be implemented using optical filters in the DRA designed to filter light with the second-Stokes wavelength. In particular, the optical filters may suppress second-Stokes light generated in any of the two or more diamond Raman amplification stages, which may limit the achievable amplification in existing Raman laser systems. As a result, the first-Stokes light may undergo highly-controlled amplification to nearly arbitrary power levels limited by damage thresholds of constituent optics rather than second-Stokes emission (or higher-order Stokes emission).

In another embodiment, though not shown inFIG. 4, the method may include a step of converting at least a portion of the first-Stokes beam to a second-Stokes beam at a second-Stokes wavelength by propagating the first-Stokes beam co-linearly with light at the second-Stokes wavelength through a diamond Raman converter including one or more third diamond gain media. In this way, the high-energy first-Stokes beam may be further converted to even longer wavelengths through another stimulated Raman scattering.

Referring now generally toFIGS. 1-4, a DR-MOPA100as disclosed herein may provide multiple benefits over currently available technologies.

For example, a DR-MOPA100as disclosed herein may provide much more flexibility with respect to pulse energy than existing diamond Raman laser technologies. Currently available beam combination techniques in diamond Raman laser technology rely on parallel architectures. However, a central challenge for the conversion efficiency in this architecture is the generation of the parasitic higher order Stokes and anti-Stokes wavelengths. Additionally, the mitigation of the thermal effects owing to the thermal load may constrain the feasibility and scalability of such a design.

In contrast, a DR-MOPA100as disclosed herein may provide high total amplification of first-Stokes wavelengths without the effects of parasitic second-Stokes due to the combination of multi-stage amplification and controlled second-Stokes suppression. Further, a DR-MOPA100disclosed herein is linearly scalable through the addition of more DRA stages112. In this way, the amplified first-Stokes beam108may be scaled until it reaches a damage threshold for incident optics.

By way of another example, a DR-MOPA100with a DRC128as disclosed herein may provide a simple and feasible architecture for achieving high powers at second-Stokes wavelengths or higher-order stokes wavelengths. For instance, amplifying the first-Stokes wavelengths while suppressing the second-Stokes wavelengths followed by converting the amplified first-Stokes wavelengths to second-Stokes wavelengths may provide higher output powers than achievable in alternative designs where both first and second-Stokes resonates in a common oscillator or amplifier. As a result, a DR-MOPA100as disclosed herein is expected to achieve over 200 times the next highest energy ever achieved in an existing diamond Raman laser system.

By way of another example, a DR-MOPA100as disclosed herein enables highly-controlled thermal management throughout the amplification process by distributing the load across many stages. In particular, the heat generated at each DRA stage112is based only on the quantum defect of the pump for that DRA stage112, which drastically simplifies the cooling design. A DR-MOPA100as disclosed herein can also be made to be very compact since the pump and diamond only need be separated by enough space for the pump light to focus.

By way of another example, a DR-MOPA100as disclosed herein may be flexibly designed to operate in either a pulsed regime (e.g., with pulses on the order of femtoseconds, picosecond, nanoseconds, or longer), or a continuous-wave (CW) regime. As an illustration, although the single pass gain may be low in the CW regime, it may generally be difficult to design a high-power single-stage multi-pass diamond Raman laser owing to the unavailability of optical isolators to handle large optical feedback from the laser to the pump source. However, the systems and methods disclosed herein including multiple amplification stages with second-Stokes suppression may be designed to provide multi-pass operation for each DRA stage112(or at least some DRA stages112) in a CW regime to increase the Raman gain without considering the optical feedback. Alternatively, the gain can be increased by using multiple diamond gain media in one or more DRA stages112as disclosed herein.

A DR-MOPA100as disclosed herein may further be utilized in a wide range of applications including, but not limited to, Lidar, infrared sensing, directed energy, range finding, target illumination, laser material processing, medical applications, generation of inaccessible wavelengths, generation of high energy pulses, or nonlinear beam combining.