Suspended particle laser of end face bi-pass pumping

Abstract

The invention relates to the technical field of solid lasers, in particular to an end face bi-pass pumping suspended particle laser which comprises a pumping source, a pumping coupling system, a gain module and a laser resonant cavity. Adjusting working parameters of the laser by using a pumping source; the pumping coupling system realizes aperture matching by using a 4f imaging system, solves the problem of pumping light divergence caused by pumping length increase by using a lens group, controls the divergence angle of the pumping light, and improves the overlapping efficiency between the pumping light and laser; the nano suspended particle laser gain medium is configured in the gain module, and the gain module adopts a bi-pass design, so that the pumping light absorption length is increased, the pumping efficiency and the pumping light intensity are improved, and the laser extraction efficiency is improved; and outputting a laser beam based on the laser resonant cavity. According to the invention, the use efficiency of the pump is improved, so that the efficiency of the laser is improved, high-power laser output is realized, the weight and the size of the laser are reduced, and the laser is lighter and more compact.

Description

Technical Field

[0001] The invention relates to the technical field of solid lasers, in particular to a suspended particle laser with end-face double-pass pumping. Background Art

[0002] Suspended particle laser material (NSPLM) is a fluid gain medium. When flowing, it has good heat transfer efficiency and quantum efficiency much higher than that of liquid laser gain medium. It is a new type of high-power laser material.

[0003] NSPLM is suspended in liquid, with a low volume share and low rare earth ion doping concentration. At the same time, due to the influence of fluorescence quenching, the doping concentration of solid gain particles cannot be too high, so the absorption coefficient is generally low, and the loss of pump light is generally high, which reduces the pump efficiency. At the same time, this gain medium NSPLM often requires a long pump path. Under this end-face pumping setting, since the laser and the pump light share the same optical path, the laser gain path will become longer, making the laser cavity loss increase exponentially with the growth of the laser gain path. The use of double-pass pumping can ensure that the pump light absorption length is only half of the laser gain path of single-pass pumping, which can greatly reduce laser loss and improve laser efficiency.

[0004] Yb³⁺-doped ions present a quasi-three-level system at room temperature. To achieve population inversion, nearly half of the population needs to be pumped to the upper energy level. The laser extraction efficiency of this system is closely related to the intensity of the pump light. The double-pass pumping method has a unique advantage. While the total energy of the absorbed pump light remains unchanged, the light intensity can be increased by 40% - 70%, thereby significantly improving the laser extraction efficiency and ultimately obtaining high-efficiency laser output. Summary of the invention

[0005] In view of the shortcomings of existing methods and the needs of practical applications, in order to promote the innovation and development of laser technology, the present invention optimizes the existing laser to achieve a significant reduction in the weight and volume of the laser, and promotes the development of the laser platform in the direction of miniaturization. At the same time, the absorption length of the laser is increased in a low rare earth ion doping concentration environment to ensure that the laser performance is improved. On the one hand, the present invention provides a suspended particle laser with end-face double-pass pumping, the laser comprising: a pump source, a pump coupling system, a gain module and a laser resonant cavity; the pump source is used to adjust the working parameters of the laser; the pump coupling system is used to match the aperture, optimize the overlap efficiency between the pump light and the laser, and optimize the laser extraction efficiency; the suspended particle laser material is configured in the gain module as a gain medium; and the laser beam is output according to the laser resonant cavity. The light in the laser resonant cavity of the present invention can be reflected back and forth, so that the intensity of the light gradually increases, forming a high-intensity laser output. In addition, by adjusting the length of the resonant cavity and the characteristics of the reflector, the laser frequency can be accurately controlled to meet the needs of different applications for specific frequency lasers.

[0006] Optionally, the end-face double-pass pumped suspended particle laser further comprises: the pump source is connected to the pump coupling system, and the pump source comprises a tunable Ti:Sapphire pump source.

[0007] Optionally, the matching of the aperture, optimization of the overlap efficiency between the pump light and the laser, and optimization of the laser extraction efficiency by the pump coupling system include: configuring a 4f imaging system, a telephoto convex lens, and a dichroic mirror in the pump coupling system; realizing beam expansion and contraction and aperture matching by the 4f imaging system; optimizing the problem of decreased overlap efficiency between the laser and the pump light caused by the divergence of the pump light by the telephoto convex lens; coating the dichroic mirror with a laser high-reflection film, and reflecting the laser based on the laser high-reflection film, thereby reducing the laser loss in the cavity. The 4f imaging system of the present invention can use optical Fourier transform technology for two-dimensional processing, and can realize beam expansion and contraction by a specific combination of optical elements, thereby ensuring that the pump light can be efficiently coupled into the laser gain medium.

[0008] Optionally, the gain module includes: configuring a gain pool in the gain module, the gain pool including a suspended particle laser material laser gain medium, so that the pump light absorption length is doubled, the pump efficiency is improved, and the problem of low absorption coefficient commonly existing in suspended particle gain media is solved.

[0009] Optionally, the suspended particle laser with end-face double-pass pumping further comprises: coating a laser high-transmittance film and a pump light high-transmittance film on the left outer surface of the gain pool. High-reflection mirror The end-face double-pass pumping method of the present invention enables the pump light to pass through the gain medium twice, thereby enhancing the pumping effect of the laser gain medium and improving the stability of the laser output. The specific coating treatment reduces the reflection and scattering of light, further reduces the fluctuation of the laser output, and makes the laser output more stable and reliable.

[0010] Optionally, the end-face double-pass pumped suspended particle laser further comprises: coating the right outer surface of the gain pool with a laser high-transmittance film and a pump light high-reflection film. The laser high-transmittance film of the present invention allows the laser to efficiently penetrate the right surface of the gain pool, reduces the extraction efficiency of the reflected laser inside the gain pool, and double-pass pumping increases the pump light intensity, thereby improving the laser extraction efficiency.

[0011] Optionally, the suspended particle laser with end-face double-pass pumping further comprises: a high-reflection mirror and a coupling output mirror are arranged in the laser resonant cavity. The present invention configures a high-reflection mirror and a coupling output mirror in the suspended particle laser with end-face double-pass pumping, which can significantly improve the stability and output power of the laser, optimize the quality of the laser beam, enhance the overall performance of the laser and expand its application range.

[0012] Optionally, configuring a high-reflection mirror and a coupling output mirror in the laser resonant cavity includes: arranging a high-reflection mirror on the lower right side of the dichroic mirror, the high-reflection mirror being coated with a laser and pump light total reflection film, arranging a coupling output mirror on the right side of the gain pool, the coupling mirror being coated with a laser high-transmittance film and a pump light high-reflection film. The present invention coats specific film systems on the dichroic mirror and the high-reflection mirror respectively, realizes effective separation of pump light and laser, avoids interference of pump light on laser output, and ensures the stability and quality of the laser beam.

[0013] Optionally, the gain medium includes Nd:NaLuF4, Nd:NaGdF4, Nd:NaYF4 and Nd:CaF2, Yb:NaLuF4, Yb:NaGdF4, Yb:NaYF4 and Yb;CaF2, a suspension of a nano solid luminescent particle or a plurality of nano solid luminescent particles as a solute, and the liquid is immersed in a liquid matrix such as C2CL4, CCL4, DMSO-d6, deuterated chloroform, cyclohexane, etc. The present invention uses nano solid luminescent particles as gain media, which helps to improve the energy conversion efficiency of the laser, and can more effectively absorb pump light and convert it into laser output.

[0014] Optionally, the suspended particle laser with end-face double-pass pumping further includes: emitting pump light through the pump source, the pump light is used to cause a population inversion of the suspended particle gain medium in the gain module to achieve energy accumulation of the gain module; the suspended particle laser with end-face double-pass pumping uses the energy accumulation to provide gain for the oscillating laser to achieve laser amplification and output; the laser resonant cavity is used to form and maintain laser oscillation, extract the energy accumulation of the gain module to achieve laser gain, and emit part of the enhanced laser to achieve laser output. The suspended particle laser with end-face double-pass pumping of the present invention has a unique working mechanism, and has the advantages of efficient energy accumulation, stability of laser oscillation, and efficient laser output, so that the laser has a wide range of application potentials in multiple fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the suspended particle laser with end-face double-pass pumping of the present invention; Figure 2 It is a schematic diagram of the interior of the distributed gain cuvette of the suspended particle laser with end-face double-pass pumping of the present invention; Figure 3 It is a schematic structural diagram of the suspended particle laser with end-face double-pass pumping of the present invention. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not need to be adopted to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, software or methods are not specifically described.

[0017] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. In addition, it should be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale.

[0018] See also Figure 1The present invention optimizes the design of existing lasers to reduce their weight and volume, and provides a practical solution for the miniaturization and portability of laser platforms. At the same time, in a low particle concentration environment, the present invention significantly improves the absorption length of the laser, ensures the excellence of the laser performance, and lays the foundation for the widespread use of lasers. The present invention provides a suspended particle laser with end-face double-pass pumping, and the suspended particle laser with end-face double-pass pumping includes the following steps: The suspended particle laser of the present invention with end-face double-pass pumping mainly includes: a pump source, a pump coupling system, a gain module and a laser resonant cavity. The present invention designs and optimizes the laser components, so that the laser has advantages in multiple aspects such as efficient pumping and optimized resonant cavity, and at the same time realizes the miniaturization and lightness of the laser, and improves the practicality and stability of the laser under various conditions.

[0019] S1. Use the pump source to adjust the laser operating parameters. The specific implementation steps and contents are as follows: In the embodiment, the pump source and the pump coupling system are interconnected, and the pump source is closely connected to the pumping process based on the efficient coupling system, ensuring efficient energy transfer and stable operation of the laser. The core component of the pump source is a tunable Ti: Sapphire laser crystal, and the wide wavelength tuning range and high power output characteristics of the pump source provide a stable and powerful power source for the pump coupling system.

[0020] Ti: Sapphire pump source and pump coupling system are the main components of the laser. The Ti: Sapphire pump source has a wide wavelength tuning range and high power output characteristics, providing a stable and powerful energy source for the laser. Through the pump coupling system, the pump source can efficiently and stably transfer energy to the target laser, ensuring the flexibility and controllability of the entire pumping process.

[0021] The above-mentioned pump source can generate extremely short laser pulses with a pulse width as low as picoseconds. The above-mentioned performance is conducive to the realization of high-precision time-resolved applications. At the same time, it has good high-power output capability, ensuring high energy density and powerful laser effect in practical applications.

[0022] The Ti:Sapphire pump source can maintain stable performance under long-term continuous operation. By adjusting the working parameters, including but not limited to pump power and crystal temperature, the Ti:Sapphire pump source can achieve precise wavelength tuning to meet the needs of different experiments and usage conditions, and has excellent spectral performance and high power output.

[0023] In the embodiment, a tunable Ti: Sapphire pump source is used, which not only has a wide spectrum coverage and extremely short pulse width, but also has high power output and excellent stability to meet various usage requirements. Furthermore, by adjusting the working parameters, wavelength tuning can be achieved to meet the needs under different experimental conditions, thereby improving the actual performance of the end-face double-pass pumped suspended particle laser.

[0024] The design of the pump source in this embodiment is only an optional implementation of the present invention. In one or some other embodiments, the design structure of the pump source can be adjusted according to the experimental conditions and the actual pumping situation, which can optimize the coupling efficiency between the pump light and the gain medium, reduce energy loss, improve pumping efficiency, help obtain higher quality laser output, reduce the thermal effect and noise interference of the pump source, and improve the overall performance of the laser.

[0025] S2. A pump coupling system is used to achieve aperture matching and improve the overlap efficiency between pump light and laser. The specific setting steps and implementation contents are as follows: In the embodiment, the 4f imaging technology is configured in the pump coupling system. The 4f imaging technology and the 4f imaging system are used in the above pump coupling system to achieve aperture matching. The specific implementation content is as follows: The pump coupling system is equipped with 4f imaging technology, that is, a corresponding 4f imaging system is designed, which not only ensures that the pump energy is evenly distributed in the laser medium and realizes efficient energy utilization, but also through the lens adjustment mechanism, the laser has flexibility in the focusing position and shape of the pump beam. Based on this, different parts of the laser medium can be accurately and meticulously pumped, thereby ensuring that the central area or the edge area can obtain uniform and effective energy supply.

[0026] Precise pump control not only improves the overall efficiency of the laser, reduces unnecessary energy loss, and outputs lasers with excellent quality and stability, but also provides a broader space for the application of lasers. Whether in scientific research experiments, industrial production or medical diagnosis, laser outputs with different needs can be met by optimizing pump control.

[0027] In addition, the introduction of the 4f imaging system enhances the scalability and adaptability of the pump coupling system. With the continuous development of laser technology and the emergence of new materials, the present invention can adapt to different pumping requirements and medium characteristics by simply adjusting and optimizing the lens system, thereby achieving wider and more efficient applications of lasers.

[0028] The pump coupling system of the present invention introduces 4f imaging technology to improve the efficiency and output power of the laser, and also has precise pump control, high energy utilization, good scalability and adaptability, providing strong technical support for the application and development of laser technology.

[0029] The related technology introduced in the pump coupling system in this embodiment is only an optional implementation mode of the present invention. The pump coupling system can be replaced in one or some other embodiments according to the target requirements of the laser and the actual situation of the pump energy. Different lasers or application scenarios have different requirements on the distribution, focusing position and shape of the pump energy. By replacing the pump coupling system, the target requirements of the laser can be better met.

[0030] S3. Configure the NSPLM laser gain medium in the gain module. The specific implementation steps and related contents are as follows: A gain pool is set in the gain module, and the gain pool also includes NSPLM laser gain medium. Furthermore, the left outer surface of the gain pool is coated with a laser and pump light high-transmittance film, and the right outer surface is coated with a laser high-transmittance film and a pump light high-reflection film. The specific implementation content is as follows: A gain pool is set in the gain module of the laser to serve as the core carrier of the laser gain medium. The above cuvette is mainly filled with NSPLM laser gain medium, which is a special medium composed of nano solid luminescent particles with extremely high optical gain performance and physical properties.

[0031] In an optional embodiment, in order to further optimize the transmission and amplification process of the laser, a cuvette is used as a gain cell, and Nd:NaLuF4, Nd:NaGdF4, Nd:NaYF4 or Nd:CaF2 nanoparticles are used, and coating treatment is performed on both sides of the cuvette. A layer of broadband high-transmittance film in the 792nm and 1060nm bands is coated on the left side of the cuvette. The main function of this film is to allow pump light and laser to pass efficiently, reduce the loss of light energy, and thus ensure the effective use of light energy; and a double-layer coating design is adopted on the right side of the cuvette. First, a layer of high-reflection film in the 792nm band is coated. The main function of this film is to reflect the unabsorbed pump light, so that it enters the gain medium of the cuvette again for secondary absorption and utilization, thereby further improving the utilization rate of the pump light. Secondly, a layer of high-transmittance film in the 1060nm band is coated on the above-mentioned high-reflection film to ensure that the generated laser can be output smoothly, thereby increasing the effective absorption length of the pump light in the gain medium and improving the laser efficiency. The 1060nm high-transmittance film can ensure that the generated laser can be output smoothly without being reflected or absorbed.

[0032] In another optional embodiment, in order to further optimize the transmission and amplification process of the laser, a cuvette is used as a gain pool, and Yb:NaLF4, Yb:NaYF4, Yb:LiYF4 or Yb:CaF2 nanoparticles are used, and coating treatment is performed on both sides of the cuvette. A layer of broadband high-transmittance film in the 976nm and 1030nm bands is coated on the left side of the cuvette. The main function of this film is to allow pump light and laser to pass efficiently, reduce the loss of light energy, and thus ensure the effective use of light energy; and a double-layer coating design is adopted on the right side of the cuvette. First, a layer of high-reflection film in the 976nm band is coated. The main function of this film is to reflect the unabsorbed pump light, so that it enters the gain medium of the cuvette again for secondary absorption and utilization, thereby further improving the utilization rate of the pump light. Secondly, a layer of high-transmittance film in the 1030nm band is coated on the above-mentioned high-reflection film to ensure that the generated laser can be output smoothly, thereby increasing the effective absorption length of the pump light in the gain medium and improving the laser efficiency. The 1030nm high-transmittance film can ensure that the generated laser can be output smoothly without being reflected or absorbed.

[0033] As a key component of the laser gain module, the choice of the material of the cuvette is crucial to the transmission and amplification effect of the laser. In this embodiment, fused quartz is selected as the material of the cuvette because it not only has excellent optical transparency and chemical stability, but also its refractive index (1.45) is basically matched with the refractive index of the two solvents to be used, Cargille's S1056 (refractive index 1.433) and 5610 (refractive index 1.45). The above refractive index matching helps to reduce the reflection loss of light at the interface between the solvent and the cuvette, thereby ensuring the efficient transmission and utilization of light energy. The above-mentioned cuvette and its corresponding coating structure not only ensure the efficient transmission and utilization of light energy, but also increase the absorption length of the pump light, significantly improve the efficiency and performance of the laser, reflect the in-depth understanding and fine control of the optimization of laser performance, and provide strong support for the application and development of lasers.

[0034] In another optional embodiment, the laser of the present invention adopts a distributed gain design, wherein the design schematic diagram of the interior of the cuvette and the distributed gain structure are specifically shown in Figure 2 , where 1 represents the pump source, 2 represents the 4f imaging system, 3 represents the telephoto convex lens, 4 represents the dichroic mirror, 5 represents the high-reflection mirror, 6 represents the external surface laser output coupling mirror and the pump light high-reflection mirror, 7 represents the external surface laser output coupling mirror and the pump light high-reflection mirror, and 8 represents the output coupling mirror.

[0035] based on Figure 2It can be seen that the interior of the cuvette is composed of dozens or hundreds of gain fluid strips and transparent windows, forming a unique fluid-solid-fluid sandwich structure. The above structural units together form an efficient gain module under linear arrangement. The above design method not only realizes the compactness of the laser, but also ensures the stable maintenance of the laminar flow state, thereby achieving a large gain volume in a compact gain module structure.

[0036] In an optional embodiment, the sandwich structure enables the gain fluid to be evenly distributed under the clamping of the transparent window, thereby avoiding the instability of the fluid flow and the unevenness of the gain distribution. At the same time, the introduction of the transparent window not only enhances the stability of the structure, but also ensures the transmittance of the laser and the clarity of the optical path. The distributed gain and fluid-solid-fluid sandwich structure can significantly improve the gain effect and stability of the laser while maintaining the compactness of the laser, which not only optimizes the performance of the laser, but also provides the possibility for further miniaturization and integration of the laser.

[0037] The special coating structure inside the cuvette not only ensures the efficient transmission and utilization of pump light and laser, but also realizes the precise control of the laser output direction, making it possible to optimize the performance of the laser.

[0038] In addition, in this embodiment, the gain medium mainly includes Yb:NaLF4, Yb:NaYF4, Yb:LiYF4 or Yb:CaF2 solid luminescent particles or a suspension with a plurality of nano solid luminescent particles as solute.

[0039] The gain medium is a key component in the laser, which is mainly responsible for absorbing the pump energy and converting it into laser radiation. In the present invention, the gain medium is specially selected from nano solid luminescent particles in Yb:NaLF4, Yb:NaYF4, Yb:LiYF4 or Yb:CaF2. The above nano-scale particles have unique physical and chemical properties, providing efficient energy conversion and laser generation mechanisms for the laser. In addition, as a gain medium, the nano solid luminescent particles have higher energy density, faster energy conversion speed and better thermal stability, which makes the gain medium have a wide range of application prospects in the field of lasers, and helps to expand the practical field of distributed gain suspended particle lasers with end-face double-pass pumping.

[0040] In this embodiment, the above-mentioned nano solid luminescent particles can be used alone or in combination to form a suspension as a gain medium. The type, concentration and properties of the nanoparticles and the suspension are selected and controlled according to actual needs, so as to achieve optimization and customization of laser performance, thereby meeting the needs of different applications.

[0041] Furthermore, the optimization design method of the gain module in the present embodiment is only an optional implementation mode of the present invention. In one or some other embodiments, the gain module can be adjusted according to the actual situation of the pump source and the gain medium. Different pump sources and gain media have different characteristics and requirements. By adjusting the gain module according to the actual situation, the performance of the pump source and the gain medium can be better matched, thereby achieving more efficient and stable laser output.

[0042] S4, outputting a laser beam based on the laser resonant cavity, the specific steps and implementation contents are as follows: The end-face double-pass pumped suspended particle laser further includes: configuring a high reflective mirror (HR) and a coupling output mirror (OC) in the laser resonant cavity, and the specific implementation contents are as follows; The suspended particle laser with end-face double-pass pumping also includes: a high-reflection mirror is arranged on the lower side of the dichroic mirror, the high-reflection mirror is coated with a laser and pump light total reflection film, a coupling output mirror is arranged on the right side of the gain cell, and the coupling mirror is coated with a laser high-transmittance film and a pump light high-reflection film.

[0043] In an optional embodiment, a double-pass pump design is used to further improve the utilization of pump energy and the efficiency of the laser. In the embodiment, a high-reflection mirror is arranged on the lower side of the dichroic mirror, and its outer surface is coated with a 1060nm broadband anti-reflection film to ensure that the laser can be fully returned.

[0044] Among them, the right side of the gain cell is the coupling output mirror, and its inner surface is coated with a 1060nm coupling output film, which is used to control the coupling output ratio of the laser while ensuring the stability and beam quality of the laser.

[0045] In this embodiment, the double-pass pumping structural features and coating method not only ensure the efficient use of pump light and the stable output of laser, but also improve the gain effect of the laser by increasing the pump absorption length, thereby realizing the in-depth optimization and control of the laser performance, and providing strong support for the application and development of lasers.

[0046] Furthermore, in this embodiment, the design method of the laser resonant cavity is only an optional condition of the present invention. In one or some other embodiments, the design method and content of the laser resonant cavity can be adjusted according to the actual needs of the laser and the output target of the laser resonant cavity. Each application has different performance requirements for the laser. By adjusting the design of the laser resonant cavity according to actual needs, customized performance of the laser can be achieved, thereby better meeting the needs of various application scenarios, so that the laser can produce higher quality laser output at the same input power.

[0047] End-pumped double-pass suspended particle lasers also include: In the suspended particle laser with end-face double-pass pumping, pump light is emitted by a pump source, and the above-mentioned pump light is used to cause a particle number inversion in the suspended particle gain medium in the gain module to achieve energy accumulation in the gain module; the distributed gain suspended particle laser with end-face double-pass pumping uses the above-mentioned energy accumulation to provide gain for the oscillating laser to achieve laser amplification and output; the laser resonant cavity is used to form and maintain laser oscillation, extract the energy accumulation of the gain module to achieve laser gain, and emit part of the enhanced laser to achieve laser output.

[0048] In an optional embodiment, the end-face double-pass pumped suspended particle laser achieves efficient laser amplification and output through its unique design and working mechanism. First, the pump source emits high-intensity pump light, which is accurately introduced into the gain module and interacts with the suspended particle gain medium therein. Under the action of the pump light, the number of particles in the suspended particle gain medium is reversed, that is, it transitions from a low energy level to a high energy level, forming a state of particle number inversion. The above process is the basis for the laser to achieve gain and is also a key step in energy accumulation.

[0049] Once the population inversion state is formed, the gain module has the ability to provide gain for the oscillating laser. When the laser oscillates in the laser resonant cavity, it will pass through the gain module many times and interact with the high-energy particles in the gain medium, thereby realizing energy transfer and accumulation. The above energy accumulation process not only enhances the intensity of the laser, but also improves the laser beam quality and stability.

[0050] As the core part of the laser, the laser resonant cavity is of vital importance in design and function. It is responsible for forming and maintaining the oscillation of the laser, ensuring that the laser is reflected and amplified multiple times in the resonant cavity. At the same time, the laser resonant cavity also extracts the energy accumulation in the gain module through its specific design, including but not limited to the coating and placement angle of the reflector, to achieve the gain and amplification of the laser, and finally the partially enhanced laser is emitted to form the final required laser output.

[0051] The gain of the end-face double-pass pumping also plays an important role, which allows the pump light to be transmitted in the gain module through a double pass, increasing the interaction time and area between the pump light and the gain medium, thereby improving the pump efficiency and laser gain.

[0052] The end-face double-pass pumped suspended particle laser of the present invention realizes efficient laser amplification and output through its unique design and working mechanism, embodies innovation and advancement in many aspects, and opens up a new path for the development and application of laser technology.

[0053] The laser resonant cavity acts as a closed optical circulation system. In the laser of the present invention, the laser energy is accumulated and amplified through multiple actions of the gain medium, such as the excitation and transition of suspended particles. The above process gradually increases the power and energy density of the laser, and finally the laser resonant cavity outputs a high-intensity laser beam.

[0054] The design of the laser resonant cavity determines the distribution of the optical path difference in the cavity, which in turn affects the interference effect of light. The above interference effect is like a sieve of the spectrum, which can filter out lasers of specific frequencies and achieve precise control of the laser frequency. By fine-tuning parameters such as the length of the resonant cavity and the curvature of the reflector, the frequency of the laser can be precisely controlled, providing an accurate laser source for scientific experiments and industrial applications.

[0055] The laser resonant cavity is not only an amplifier of laser energy, but also an optimizer of beam quality. By optimizing the structure and parameters of the resonant cavity, the divergence angle, cross-sectional shape and other parameters of the laser beam can be controlled, the diffusion of the beam can be reduced, the directionality and stability of the beam can be improved, the laser beam can be shaped and focused, the directionality and stability of the beam can be improved, and higher quality laser output can be obtained.

[0056] In the suspended particle laser with end-face double-pass pumping, the laser resonant cavity is the key to achieving efficient energy utilization. Its unique design allows the pump light to be evenly irradiated on the suspended particle gain medium, achieving uniform distribution and efficient conversion of laser energy, making the laser beam more uniform and stable.

[0057] The laser resonant cavity can also control the mode of the laser to display different laser modes. By adjusting the structure and parameters of the resonant cavity, the laser mode can be flexibly selected and controlled, including but not limited to the fundamental mode and multi-mode. The diversity of modes enables the laser to adapt to different application scenarios, such as material processing, communication transmission, medical diagnosis, etc., to meet the needs of different practical applications for laser modes.

[0058] The laser resonant cavity plays an important role in the suspended particle laser with end-face double-pass pumping, such as storing and amplifying laser energy, selecting and stabilizing laser frequency, improving laser beam quality, and controlling laser mode. The realization of the above functions helps to improve the performance and application range of the laser.

[0059] For details on the structure of the suspended particle laser with end-face double-pass pumping, please refer to Figure 3 , Figure 3 9 indicates NSPLM as a gain medium, 10 indicates an optical window, 11 indicates a laser, 12 indicates a pump, 13 indicates a distributed gain architecture, and 14 indicates a laser.

[0060] In an optional embodiment, the invention provides a suspended particle laser with end-face double-pass pumping, the laser comprising a pump source, a pump coupling system, a gain module and a laser resonant cavity, and performs the specific steps of the relevant embodiments of the invention. The distributed gain suspended particle laser with end-face double-pass pumping of the invention has a complete structure, objective stability, and can improve the overall applicability and practical application ability of the invention.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A suspended particle laser with end-face double-pass pumping, characterized in that: The end-face double-pass pumped suspended particle laser comprises: a pump source, a pump coupling system, a gain module and a laser resonant cavity; Using the pump source to adjust the operating parameters of the laser; Matching the aperture, optimizing the overlap efficiency between the pump light and the laser, and optimizing the laser extraction efficiency through the pump coupling system; Disposing a suspended particle laser material as a gain medium in the gain module; A laser beam is outputted according to the laser resonant cavity.

2. The suspended particle laser with end-face double-pass pumping according to claim 1, characterized in that: The end-face double-pass pumped suspended particle laser also includes: The pump source is in communication with the pump coupling system, and the pump source comprises a tunable Ti:Sapphire pump source.

3. The suspended particle laser with end-face double-pass pumping according to claim 1, characterized in that: The matching of the aperture, optimizing the overlap efficiency between the pump light and the laser, and optimizing the laser extraction efficiency by the pump coupling system include: A 4f imaging system, a telephoto convex lens and a dichroic mirror are configured in the pump coupling system; The beam expansion and contraction and aperture matching of the light beam are realized by the 4f imaging system; The problem of decreased overlap efficiency between laser and pump light caused by optimizing the divergence of pump light using the telephoto convex lens; A laser high-reflection film is coated on the dichroic mirror, and the laser high-reflection film reflects the laser, thereby reducing the laser loss in the cavity.

4. The suspended particle laser with end-face double-pass pumping according to claim 1, characterized in that: The gain module comprises: A gain pool is configured in the gain module, and the gain pool includes a suspended particle laser material laser gain medium.

5. The suspended particle laser with end-face double-pass pumping according to claim 4, characterized in that: The end-face double-pass pumped suspended particle laser also includes: A laser high-transmittance film and a pump light high-transmittance film are plated on the left outer surface of the gain cell.

6. The suspended particle laser with end-face double-pass pumping according to claim 4, characterized in that: The end-face double-pass pumped suspended particle laser also includes: The right outer surface of the gain cell is plated with a laser high-transmittance film and a pump light high-reflection film.

7. The suspended particle laser with end-face double-pass pumping according to claim 1, characterized in that: The end-face double-pass pumped suspended particle laser also includes: A high-reflection mirror and a coupling output mirror are arranged in the laser resonant cavity.

8. The suspended particle laser with end-face double-pass pumping according to claim 7, characterized in that: The configuration of a high-reflection mirror and a coupling output mirror in the laser resonant cavity comprises: A high-reflection mirror is arranged at the lower right side of the dichroic mirror, and the high-reflection mirror is coated with a laser and pump light total reflection film. A coupling output mirror is arranged on the right side of the gain cell, and the coupling mirror is coated with a laser high-transmittance film and a pump light high-reflection film.

9. The suspended particle laser with end-face double-pass pumping according to any one of claims 1 to 7, characterized in that: The gain medium includes Nd:NaLuF4, Nd:NaGdF4, Nd:NaYF4 and Nd:CaF2, Yb:NaLuF4, Yb:NaGdF4, Yb:NaYF4 and Yb;CaF2, a suspension of one nano solid luminescent particle or multiple nano solid luminescent particles as solute, and the liquid is immersed in a liquid matrix such as C2CL4, CCL4, DMSO-d6, deuterated chloroform, cyclohexane, etc.

10. The suspended particle laser with end-face double-pass pumping according to claim 1, characterized in that: The end-face double-pass pumped suspended particle laser also includes: The pump source emits pump light, and the pump light is used to cause a population inversion of a suspended particle gain medium in the gain module to achieve energy accumulation of the gain module; The end-face double-pass pumped suspended particle laser uses the energy accumulation to provide gain for the oscillating laser, thereby achieving laser amplification and output; The laser resonant cavity is used to form and maintain laser oscillation, extract the energy accumulation of the gain module to achieve laser gain, and emit partially enhanced laser light to achieve laser output.

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