Solid resonant cavity adjusting device and method for generating mid-infrared femtosecond laser

Abstract

The invention provides a solid resonant cavity adjusting device and method for intermediate infrared femtosecond laser generation. The solid resonant cavity adjusting device comprises an induction adjusting system, a light source system, a lens system, a transition resonant cavity system, a dispersion compensation system and a collimation system. The induction adjusting system collects light beam intensity distribution. The light source system is used for generating various types of light beams. The lens system is used for focusing and adjusting the light beams. The transition resonant cavity system directs the light beam to the dispersion compensation system. The dispersion compensation system accurately compensates for dispersion effects caused by the optical medium. According to the invention, through combination of the induction plate and the transition cavity structure, efficient compensation of light beam dispersion by inserting the prism in the middle infrared band is realized, and the device has the advantages of simple operation, high detection precision and strong real-time adjustment capability. The method can be widely applied to the fields of laser beam regulation and control, precise optical measurement, laser communication, optical imaging and the like, and has remarkable advantages in the aspect of improving the precision and stability of a laser system.

Description

Technical Field

[0001] The present invention relates to the field of optical adjustment and laser technology, and in particular to a solid resonant cavity adjustment device and method for generating mid-infrared femtosecond lasers. Background Art

[0002] Laser technology is continuously expanding its application in cutting-edge fields such as optical communications, scientific experiments, and industrial processing. Mid-infrared laser systems, in particular, are becoming a key driver of development in these areas. In these applications, beam quality, stability, and dispersion control are directly related to the overall performance of the system and are becoming increasingly important.

[0003] In practice, high-power lasers and multi-beam combining systems face daunting challenges. Dispersion, like a hidden reef, severely interferes with beam propagation characteristics, significantly compromising beam quality and leading to a decline in system performance. During high-power laser operation, the high-intensity energy impact further amplifies dispersion, negatively impacting beam focusing accuracy and energy distribution uniformity. Furthermore, in multi-beam combining systems, variations in dispersion between beams can lead to phase inconsistencies in the combined beams, severely hindering efficient beam superposition and coordinated operation.

[0004] Currently, dispersion compensation technology in the mid-infrared band is facing severe technical bottlenecks. Traditional dispersion compensation strategies mostly rely on single optical elements or use traditional beam path adjustment methods. In the mid-infrared band, especially when the beam path is complex and the wavelength is long, these methods are inadequate. For example, in high-power laser processing, the complex optical path layout and high energy density make it impossible for traditional prism compensation methods to achieve precise adjustment. At the same time, traditional dispersion compensation devices often have complex structures and cumbersome operating procedures, making it difficult to quickly and accurately adjust dispersion in real time in practical applications, which undoubtedly restricts the development of related fields. Summary of the Invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a solid resonant cavity adjustment device and method for mid-infrared femtosecond laser generation, so as to improve the beam quality and stability of the laser system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A solid resonant cavity adjustment device for mid-infrared femtosecond laser generation, comprising:

[0008] a light source system for generating a pump beam;

[0009] The lens system is used to adjust the divergence angle, spot size and optical axis direction of the light beam to ensure that the shape of the light beam remains stable during transmission;

[0010] The transition resonant cavity system is used to output a laser beam with excellent beam quality. This laser beam serves as the guiding light source of the mid-infrared solid-state laser dispersion compensation system, providing stable and high-quality optical signal input for the subsequent dispersion compensation process.

[0011] Collimation system, used to assist in building the transition resonant cavity system;

[0012] Dispersion compensation system, used for dispersion adjustment;

[0013] Sensing and conditioning systems are used to sense, condition and monitor optical signals.

[0014] Preferably, the light source system comprises a light source module and an isolator module; the light source module is used to generate a pump light beam; and the isolator module is used to prevent the reverse light beam from returning to the light source module.

[0015] Preferably, the lens system includes two symmetrically arranged collimating modules for adjusting the divergence angle, spot size and optical axis direction of the pump light beam generated by the light source module.

[0016] Preferably, the transition resonant cavity system includes a gain medium, two plano-concave mirrors, and two transition end mirrors; the two plano-concave mirrors are symmetrically arranged on both sides of the gain medium; the plano-concave mirrors are used to reflect the light beam onto the transition end mirrors; the transmittance of the transition end mirrors is <5%.

[0017] Preferably, the collimation system includes a HeNe laser, a plane mirror and a double-sided sensing plate; the plane mirror is used to reflect the light beam emitted by the HeNe laser onto the double-sided sensing plate.

[0018] Preferably, the dispersion compensation system comprises a rotational translation stage and a prism pair; the prism pair is mounted on the rotational translation stage and is used to perform dispersion adjustment on the light beam passing through the transition end mirror and reflect the light beam to the induction adjustment system.

[0019] Preferably, the sensing and adjustment system includes a photosensitive plate, a beam splitter, an adjustable end mirror, a charge-coupled device, an attenuation plate, a measuring unit, and a control unit; the light beam refracted by the prism passes through the photosensitive plate and is divided into two beams by the beam splitter, one of which is irradiated onto the charge-coupled device through the attenuation plate, and the other is irradiated onto the adjustable end mirror; the measuring unit is used to measure the power change of the optical path; the control unit is used to control the operation of the system; the photosensitive plate adopts a 160μm temperature-sensitive photosensitive film; the beam splitter is a polarization-independent beam splitter, and its splitting ratio is set to 80:20, 80% of the incident light is directed into the cavity to maintain the complex optical process in the cavity; the remaining 20% of the light is split into a mid-infrared charge-coupled device as detection light for subsequent monitoring and analysis of the optical state in the cavity.

[0020] A solid resonant cavity adjustment method for mid-infrared femtosecond laser generation comprises the following steps:

[0021] Step 1. Build the light source system: Configure the light source module, select the appropriate wavelength and power; install the isolator module to ensure that the light source is not affected by the reverse beam; install two collimation modules to focus the pump light source on the center of the gain medium;

[0022] Step 2: Build the collimation system to lay the foundation for the subsequent construction of the transition cavity system. To ensure that its height is consistent with the height of the light source system, the HeNe laser needs to pass through two apertures at the same height as the light source system in sequence. The apertures are placed one far and one near to maintain the linearity of the collimated light source. The double-sided sensor plate is fixed with a clamp and placed on a three-dimensional adjustment frame. It is then placed at a position where the light path of the light source system and the HeNe laser overlap. Using the position of the light source on one side as a reference, the angle of the plane mirror is adjusted to ensure that the light sources on both sides are highly aligned.

[0023] Step 3: Build the transition cavity system: Based on the design parameters, add a plano-concave mirror and adjust its deflection angle to pass through the left and right apertures. Place two transition end mirrors according to the He-Ne laser. Use one transition end mirror as the transition mirror for the adjustable end mirror. Add a measurement unit after the adjustable end mirror to determine whether the transition cavity is resonant. Optimize the transition cavity laser and use the laser light transmitted by the transition end mirror as the guide light for building the dispersion compensation system.

[0024] Step 4: Build the dispersion compensation system: Using the laser light transmitted from the transition end mirror in step 2 as the guide light, place the two prism pairs on a rotation stage and adjust them by offsetting them.

[0025] Step 5: Build the sensing and adjustment system: Place the beam splitter, adjustable end mirror, charge-coupled device, attenuator, and control unit in sequence according to the guide light passing through the dispersion compensation system.

[0026] Step 6: Combine the manual mode coarse adjustment with the electric mode fine adjustment to complete the adjustment of the induction adjustment system;

[0027] Step 7. Careful observation is required during step 6. If the optical paths are highly overlapped in the horizontal and vertical directions, the power of the measurement unit will increase. At this time, remove the transition end mirror, complete the prism insertion and light output adjustment, and further optimize the charge coupled device power.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. High-precision dispersion compensation: Through the coordinated adjustment of the transition resonator and prism pair, high-precision dispersion compensation of the laser beam in the mid-infrared band is achieved, ensuring stable beam quality.

[0030] 3. Real-time adjustment and high stability: The real-time detection and feedback mechanism of the sensing plate, combined with the output adjustment of the transition resonant cavity, can continuously monitor and adjust the beam state during beam propagation, ensuring high stability and high efficiency.

[0031] 4. Simplified design and easy implementation: The device adopts a simplified design scheme, has a compact structure, is easy to integrate into existing laser systems, and has a low cost, making it suitable for widespread application in scientific research and industrial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention;

[0033] Figure 2 It is a diagram of four different orientations of the light spot;

[0034] Figure 3 This is a schematic diagram of the sensor plate and the transition cavity working together to achieve prism dispersion compensation in the mid-infrared band (upper and lower directions);

[0035] Figure 4 This is a schematic diagram of the sensor plate and the transition cavity working together to achieve prism dispersion compensation (front and back directions) in the mid-infrared band;

[0036] Figure 5 It is a flow chart of the optical path adjustment method of the present invention.

[0037] in:

[0038] 11. Photosensitive plate; 12. Beam splitter; 13. Adjustable end mirror; 14. Charge-coupled device; 15. Attenuator; 16. Measuring unit; 17. Control unit; 21. Light source module; 22. Isolator module; 31. Collimation module; 41. Plano-concave mirror; 43. Transition end mirror; 45. Gain medium; 51. Prism pair; 61. He-Ne laser; 62. Plane mirror; 63. Double-sided sensing plate. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] like Figures 1 to 5 As shown, a solid resonant cavity adjustment device for mid-infrared femtosecond laser generation includes:

[0041] a light source system for generating a pump beam;

[0042] The lens system is used to adjust the divergence angle, spot size and optical axis direction of the light beam to ensure that the shape of the light beam remains stable during transmission;

[0043] The transition resonant cavity system is used to output a laser beam with excellent beam quality. This laser beam serves as the guiding light source of the mid-infrared solid-state laser dispersion compensation system, providing stable and high-quality optical signal input for the subsequent dispersion compensation process.

[0044] Collimation system, used to assist in building the transition resonant cavity system;

[0045] Dispersion compensation system, used for dispersion adjustment;

[0046] Sensing and conditioning systems are used to sense, condition and monitor optical signals.

[0047] In this embodiment, the light source system includes a light source module 21 and an isolator module 22; the light source module 21 is used to generate a pump beam, which is one of the basic elements for generating lasers and supports multiple beam modes, including continuous wave and pulsed light output; the isolator module 22 is used to prevent the reverse light beam from returning to the light source module 21, thereby protecting the stable operation of the light source module 21.

[0048] In this embodiment, the lens system includes two symmetrically arranged collimating modules 31 for adjusting the divergence angle, spot size and optical axis direction of the pump light beam generated by the light source module 21 .

[0049] In this embodiment, the transition resonant cavity system includes a gain medium 45, two plano-concave mirrors 41, and two transition end mirrors 43. The two plano-concave mirrors 41 are symmetrically arranged on either side of the gain medium 45. The plano-concave mirrors 41 are used to reflect the light beam onto the transition end mirrors 43. This system introduces a short cavity structure based on the existing long cavity structure to construct a transition resonant cavity, or transition cavity. Specifically, a transition end mirror 43 is added at the end of the long arm (before the dispersion compensation system) to serve as an output coupling mirror, while the other transition end mirror 43 remains unchanged. To achieve sufficient energy resonance within the transition cavity and meet sufficient output power requirements for easy detection, the transition end mirrors 43 in both arms use output coupling mirrors with low transmittance (T < 5%). Through the optimized design of the laser gain medium 45 and the transition resonant cavity geometry, the transition resonant cavity can output a laser beam with excellent beam quality at high output power. This laser beam serves as the guiding light source for the mid-infrared solid-state laser dispersion compensation system, providing stable and high-quality optical signal input for the subsequent dispersion compensation process.

[0050] In this embodiment, the collimation system includes a HeNe laser 61 , a plane mirror 62 and a double-sided sensing plate 63 ; the plane mirror 62 is used to reflect the light beam emitted by the HeNe laser 61 onto the double-sided sensing plate 63 .

[0051] In this embodiment, the dispersion compensation system includes a rotation stage and a prism pair 51. Using a symmetrical optical path design, the prism pair 51 is mounted on a rotation stage with a rotational accuracy of 20 μm. It is used to adjust the dispersion of the light beam passing through the transition end mirror 43 and reflect it to the sensing adjustment system. This precise offset adjustment achieves more accurate dispersion adjustment and greater system stability.

[0052] In this embodiment, the sensing and adjustment system includes a photosensitive plate 11, a beam splitter 12, an adjustable end mirror 13, a charge-coupled device 14, an attenuation plate 15, a measurement unit 16, and a control unit 17. These components work together to sense, adjust, and monitor optical signals, a key step in ensuring the precise operation of the entire optical system. The light beam refracted by the prism pair 51 passes through the photosensitive plate 11 and is split into two beams by the beam splitter 12. One beam passes through the attenuation plate 15 and strikes the charge-coupled device 14, while the other strikes the adjustable end mirror 13. Both sides of the photosensitive plate 11 utilize a 160μm temperature-sensitive photosensitive film that responds to light in the 2-13μm wavelength range. When laser light is irradiated onto the photosensitive plate 11 and the temperature is above 30°C, the film exhibits different colors depending on the temperature based on the principle of thermochromism, thereby visualizing the mid-infrared light and facilitating visual observation. The photosensitive plate 11 uses aluminum alloy sheets as its substrate, and utilizes the good thermal conductivity of aluminum alloy to effectively promote heat dissipation and ensure that the photosensitive film operates in an appropriate temperature range. At the same time, grid lines are engraved in the photosensitive area to assist in the light spot alignment operation and improve the accuracy of light spot positioning. The edges of the double-sided photosensitive plate 11 are specially treated and are not absolutely smooth. By enhancing the surface roughness, the scattering of light is promoted. When two beams of light overlap and pass through its edge, a diffuse reflection effect occurs, generating a linear halo, which is helpful for light path observation and debugging. In addition, to ensure accurate monitoring and analysis of optical signals, the double-sided photosensitive plate 11 is properly installed on a three-dimensional adjustment frame with precise adjustment functions in the X, Y, and Z directions. The three-dimensional adjustment frame can accurately position the double-sided photosensitive plate 11 to the target position, thereby achieving efficient reception of optical signals in specific areas. After being installed on the three-dimensional adjustment frame supporting platform, a specially designed clamp is used to tightly fit and fix the edges of the double-sided photosensitive plate 11, providing reliable mechanical fastening force without affecting its optical performance, effectively resisting position deviation caused by external interference factors such as vibration and airflow during system operation, and ensuring the accuracy of optical signal detection.

[0053] The beam splitter 12 is polarization-independent, with a splitting ratio of 80:20. This means that 80% of the incident light is directed into the cavity to maintain the complex optical processes within the cavity; the remaining 20% is split and sent to the mid-infrared charge-coupled device 14 as probe light for subsequent monitoring and analysis of the optical state within the cavity.

[0054] The adjustable end mirror 13 in the long-cavity model is mounted on a five-dimensional adjustment mount. This mount features both manual and motorized adjustment modes. The manual mode, achieved via a knob or fine-tuning screw, is suitable for coarse adjustments during rapid alignment. The motorized mode, driven by a control unit 17, achieves beam adjustment with a displacement accuracy of up to 20 μm per grid and an angular accuracy of 1.8°. This meets the optical system's requirements for high-precision beam control and provides a flexible and reliable adjustment method for precise beam shaping and positioning.

[0055] To prevent the CCD 14 from being damaged, the CCD 14 and the attenuation plate 15 at the front end can be automatically monitored by the control unit 17 at the same time, flexibly adjusting the signal strength entering the CCD 14 and performing signal data extraction and collection.

[0056] After the coarse adjustment of the human eye is completed, the control unit 17 with intelligent computing and control capabilities starts running immediately. The system relies on a high-performance computer platform and a dedicated interface built through Python programming to perform in-depth and accurate analysis (shape, position, intensity) of the light spot change data collected by the charge-coupled device 14. The control unit 17 performs an in-depth analysis of the parsed data based on the Python algorithm model, and then feeds back a precise adjustment signal to the adjustable end mirror 13. The adjustable end mirror 13 uses a built-in high-precision displacement and angle adjustment device to accurately adjust its own translation distance, pitch angle and deflection angle based on the feedback signal, ensuring that the light beam can be positioned and calibrated with micron-level precision in both the horizontal and vertical directions. At the same time, the control unit 17 monitors the output changes of the measuring unit 16 in real time, and uses it as a key quantitative basis for determining whether the final laser is successfully generated and whether the laser output is stable. Through this automated adjustment and real-time feedback mechanism, the system can efficiently complete the beam path calibration and significantly improve the adjustment accuracy and operating efficiency.

[0057] Measurement unit 16 can be a thermal power meter capable of measuring a wide spectral range in the mid-infrared band. Alternatively, it can be a photoelectric detection power meter with a fast response speed, suitable for measuring pulsed light sources or short-duration high-power light sources. This allows for flexible reflection of whether laser light is being generated within the cavity, optimizing system adjustment and calibration, and improving the performance of the entire dispersion compensation system.

[0058] The light source module 21 generates a basic light beam and supports a variety of laser types and wavelengths, including continuous-wave (CW) lasers, pulsed lasers, and ultrashort-pulse lasers. Fiber lasers, solid-state lasers, and semiconductor lasers can be used as the basic light source to meet different needs. The isolator module 22 uses an optical isolator to prevent the reverse propagation of the light beam, protecting the light source module 21 from damage caused by reflected light. This isolation function is achieved through nonlinear optical materials or Faraday rotators, making it suitable for high-power laser systems and improving the stability and reliability of the overall operation of the light source system.

[0059] The collimation module 31 includes a high-precision lens group or a fiber collimator, which is used to adjust the divergence angle and spot size of the light beam to ensure that the light beam maintains stable directionality and shape when passing through.

[0060] The transition resonant cavity system is capable of generating stable and high-power lasers in the mid-infrared band. Prior to this, it is necessary to strictly adjust the overlap between the collimation system and the light source system as the guide light of the transition cavity. In order to achieve sufficient energy resonance in the cavity and meet the sufficient output power requirements for easy detection, the two transition end mirrors 43 of the transition resonant cavity system both use output coupling mirrors with low transmittance (T<5%), and positioning apertures are placed on both sides. A measurement unit 16 is placed behind one of the end mirrors to detect the light output adjustment and optimization monitoring of the other transition end mirror 43.

[0061] The dispersion compensation system uses a prism pair 51, and the material may include optical glass, optical quartz, fluoride (such as calcium fluoride), sapphire, etc.

[0062] This device is suitable for mid-infrared light beam dispersion compensation and adjustment scenarios. Through the precise coordination of the transition resonant cavity system and the prism pair 51, it ensures that after the light beam undergoes dispersion compensation, the spatial structure of the light beam is effectively restored, and the quality and propagation characteristics of the output light beam meet the predetermined requirements, meeting the strict requirements of high-precision optical systems for light beam consistency and stability.

[0063] A solid resonant cavity adjustment method for mid-infrared femtosecond laser generation comprises the following steps:

[0064] Step 1: Build the light source system: Configure the light source module 21 and select the appropriate wavelength and power; install the isolator module 22 to ensure that the light source is not affected by the reverse beam; install two collimation modules 31 to focus the pump light source on the center of the gain medium 45;

[0065] Step 2: Build the collimation system to lay the foundation for the subsequent construction of the transition cavity system. To ensure that its height is consistent with the height of the light source system, the HeNe laser 61 needs to pass through two apertures at the same height as the light source system, one far and one near, to maintain the linearity of the collimated light source. The double-sided sensor plate 63 is fixed with a clamp and placed on a three-dimensional adjustment frame. It is then placed at a position where the optical path of the light source system and the HeNe laser 61 overlap. Using the position of the light source on one side as a reference, the angle of the plane mirror 62 is adjusted to ensure that the light sources on both sides are highly aligned.

[0066] Step 3: Build the transition cavity system: According to the design parameters, add a plano-concave mirror 41 and adjust its deflection angle to pass through the left and right apertures; place two transition end mirrors 43 respectively according to the He-Ne laser 61; one of the transition end mirrors 43 serves as a transition mirror for the adjustable end mirror 13, and a measurement unit 16 is added after the adjustable end mirror 13 to determine whether the transition cavity is resonant; optimize the transition cavity laser, and use the laser light transmitted by the transition end mirror 43 as the guide light for building the dispersion compensation system;

[0067] Step 4: Build a dispersion compensation system: Using the laser light transmitted from the transition end mirror 43 in step 2 as the guide light, place the two prism pairs 51 on a rotation stage and adjust them by offsetting.

[0068] Step 5: Build the sensing and adjustment system: according to the guide light passing through the dispersion compensation system, place the beam splitter, adjustable end mirror 13, charge coupled device 14, attenuation plate 15 and control unit 17 in sequence;

[0069] Step 6: Combine the manual mode coarse adjustment with the electric mode fine adjustment to complete the adjustment of the induction adjustment system;

[0070] (1) Achieve longitudinal (upper and lower) alignment of the optical path: First, block the adjustable end mirror 13, and use the charge coupled device 14 and the attenuation plate 15 to measure and record the overall contour of the transmitted light spot under the detection of the control unit 17; secondly, use a special clamp to clamp the double-sided sensing plate 63, and use a three-dimensional adjustment frame to fix it for precise adjustment and recording of the position. The light spot can be divided into upper and lower directions according to the X-axis direction. Use the double-sided sensing plate 63 to block the upper half of the light spot, and the human eye captures the light beam shape on both sides of the double-sided sensing plate 63. Ideally, it should be as follows Figure 3 As shown in (a1), compare the beam shape displayed on the sensor board to see if it is close to the expected Figure 3 (a1). If something like Figure 3 (b1)(c1), manually adjust the pitch angle of the adjustable end mirror 13 until the shape observed by the human eye is close to (a1). Afterwards, use the charge coupled device 14 and the attenuation plate 15) to record the shape of the lower half of the light spot at this time. The control unit 17 compares the difference with the lower half of the light spot measured previously, and after calculation, feedback and adjusts the adjustable end mirror 13 until the lower half of the light spot measured at this time is almost the same as the lower half of the light spot measured previously. In this way, the upper half of the light spot should also overlap with the upper half of the light spot measured previously. Under ideal conditions, the double-sided sensing plate 63 is used to block the lower half of the light spot, and the left and right sides of the double-sided sensing plate 63 should be as follows. Figure 3 (a2) If there is any deviation, Figure 3 As shown in (b2) and (c2), it can be used to detect whether the longitudinal (up and down) direction of the optical path is completely aligned.

[0071] (2) Achieve horizontal (front-to-back) alignment of the light path: The light spot can be divided into directions based on the Y-axis. Use the double-sided sensing plate 63 to block the rear half of the light spot, and the human eye captures the beam shape on both sides of the double-sided sensing plate 63. Ideally, it should be as follows Figure 4 (d1) is shown, compare the beam shape displayed on the sensor plate to see if it is close to the expected pattern (d1). If a shape similar to (e1) (f1) appears, manually adjust the reversal angle of the adjustable end mirror 13 until the shape observed by the human eye is close to Figure 4 (d1). Afterwards, the charge coupled device 14 and the attenuation plate 15 are used to record the shape of the front half of the light spot at this time. The control unit 17 compares the difference between it and the front half of the overall light spot measured previously, and after calculation, feedback is given and the adjustable end mirror 13 is adjusted until the front half of the light spot measured at this time is almost the same as the front half of the light spot measured at the beginning. In this way, the back half of the light spot should also have achieved the overlap with the back half of the light spot measured previously. Under ideal conditions, the double-sided sensing plate 63 is used to block the front half of the light spot at this time, and the left and right sides of the double-sided sensing plate 63 should be as follows. Figure 4 (d2) If there is any deviation, Figure 4 As shown in (e2)(f2), it can be used for detection.

[0072] Step 7. Careful observation is required during step 6. If the optical paths are highly overlapped in the horizontal and vertical directions, the power of the measuring unit 16 will increase. At this time, the transition end mirror 43 is removed, the prism pair 51 is inserted to adjust the light output, and the power of the charge coupled device 14 is further optimized.

[0073] Example 1

[0074] The light source system consists of a semiconductor laser (LD) with a diameter of 105 μm, a numerical aperture of 0.22 (NA), a wavelength of 793 nm, and a maximum output power of 30 W. The pump light is collimated and focused onto the gain medium 45 via a 1:1 magnification telescope system composed of two plano-convex mirrors with the same focal length (f = 100 mm).

[0075] The double-sided sensing plate 63 uses two identical sensing plates. To ensure their height matches that of the light source system, the HeNe laser 61 must sequentially pass through two apertures at the same height as the light source system. The apertures are positioned one far away and one near (two points define a line) to maintain the linearity of the collimated light source. The double-sided sensing plate 63 is secured with a clamp and placed on a three-dimensional adjustment mount. It is then positioned so that the optical path of the light source system and the HeNe laser 61 overlap. Using the position of the left light source as a reference, the angle of the plane mirror 62 is adjusted to achieve a high degree of overlap between the left and right light sources. This achieves collimated focusing of the pump light and the HeNe collimated light.

[0076] Example 2

[0077] Two plano-concave mirrors 41 and a transition end mirror 43 form a transition cavity shape, and a power meter is used to measure the laser generated by this cavity shape. The gain medium 45 is an a-cut Tm:CYA crystal, 4at.% doped, with a size of 3mm×3mm×6.1mm. Both sides of the crystal are coated with an anti-reflection film (AR) of 1900-2100nm. The adjustable end mirror 13 is a high-reflectivity mirror in the 2um band. The curvature radius of the plano-concave mirror is 100mm, and the surface is coated with a high-reflectivity film (R>99.7%) in the 1850nm-2100nm band. The two transition end mirrors 43 use output coupling mirrors (OC) with a transmittance of 2% and 5%, respectively. The prism pair 51 is made of CaF2 and is placed in parallel. The measurement unit 16 uses an OPHIR NOVA II power meter with a range of 3W. After the 2μm laser passes through, a prism pair 51 is placed in parallel. Two identical sensing plates are used at the photosensitive plate 11 to realize the prism pair 51 emitting light in the 2μm band.

[0078] Principle of the invention:

[0079] The present invention is based on the cooperative working principle of the induction plate and the transition resonant cavity, combined with the dispersion compensation effect of the prism 51, to achieve precise adjustment and optimized output of the laser beam in the mid-infrared band. Its principle is as follows:

[0080] 1. Transition Resonator System Laser Generation and Regulation: The transition resonator system generates high-quality laser beams in the mid-infrared band by optimizing the gain medium and cavity geometry. This system provides a stable guide beam for subsequent dispersion compensation and ensures the stability and consistency of the laser output wavelength by precisely controlling the resonator's operating state.

[0081] 2. Prism Pair 51 Dispersion Compensation: Prism pair 51 is inserted into the beam path. By precisely adjusting the angle and position of the prisms, the propagation speed differences of beams of different wavelengths are adjusted, thereby effectively reducing the dispersion effect and ensuring that the spatial structure of the beam remains consistent, allowing the laser beam to maintain an optimal wavefront shape during propagation.

[0082] 3. Beam morphology and propagation monitoring: The sensing plate and charge-coupled device 14 are placed in the beam path to monitor in real time the morphological changes of the beam after dispersion compensation through the prism 51 (cross-sectional morphology of the beam, spot size and intensity distribution).

[0083] 4. Real-time Feedback and Adjustment: After the light beam passes through the prism pair 51 and the sensor system, the control system can adjust the beam path in real time based on the feedback from the charge-coupled device 14. The beam path can be fine-tuned manually or through an electric fine-tuning mechanism (such as a stepper motor or piezoelectric actuator) to ensure that the output beam meets the expected quality requirements.

[0084] The present invention's method for achieving 51° dispersion compensation for mid-infrared prisms, achieved through the collaborative use of a sensing plate and a transition resonant cavity, effectively improves the quality and stability of mid-infrared laser beams and is widely used in high-precision optical adjustment, laser debugging, optical experiments, and optical communications. This invention provides an efficient, stable, and economical solution, helping to advance the application and development of laser technology in the mid-infrared band.

[0085] The device relies on a transition resonant cavity system to stably generate mid-infrared lasers and cleverly uses a prism pair 51 to effectively implement dispersion compensation. At the same time, the sensor plate and charge-coupled device 14 are used to perform all-round, high-precision detection and fine-tuning of the light beam. Through the deep collaboration between the sensor plate and the transition resonant cavity system, the guide beam can be ensured to be output stably throughout the entire laser output process. After the prism pair 51 is inserted, the propagation path of the light beam can be accurately corrected, reducing the beam distortion caused by dispersion, greatly improving the beam quality, and providing a solid guarantee for the performance leap of the mid-infrared laser system.

[0086] Therefore, the dispersion compensation method and device of the present invention can effectively improve the beam quality and stability of laser systems, and are widely used in fields such as mid-infrared laser debugging, optical experiments, laser communications, and high-power laser transmission. This invention provides reliable technical support for dispersion compensation in mid-infrared laser systems, promotes technological progress in related fields, and offers a new solution for the widespread application of laser technology.

Claims

1. A solid resonant cavity adjustment device for mid-infrared femtosecond laser generation, characterized in that: include: a light source system for generating a pump beam; The lens system is used to adjust the divergence angle, spot size and optical axis direction of the light beam to ensure that the shape of the light beam remains stable during transmission; The transition resonant cavity system is used to output a laser beam with excellent beam quality. This laser beam serves as the guiding light source of the mid-infrared solid-state laser dispersion compensation system, providing stable and high-quality optical signal input for the subsequent dispersion compensation process. Collimation system, used to assist in building the transition resonant cavity system; Dispersion compensation system, used for dispersion adjustment; Sensing and conditioning systems are used to sense, condition and monitor optical signals.

2. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 1, characterized in that: The light source system comprises a light source module (21) and an isolator module (22); the light source module (21) is used to generate a pump light beam; and the isolator module (22) is used to prevent a reverse light beam from returning to the light source module (21).

3. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 1, characterized in that: The lens system comprises two symmetrically arranged collimating modules (31) for adjusting the divergence angle, spot size and optical axis direction of a pump light beam generated by a light source module (21).

4. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 1, characterized in that: The transition resonant cavity system comprises a gain medium (45), two plano-concave mirrors (41), and two transition end mirrors (43); the two plano-concave mirrors (41) are symmetrically arranged on both sides of the gain medium (45); the plano-concave mirrors (41) are used to reflect the light beam onto the transition end mirrors (43); and the transmittance of the transition end mirrors (43) is less than 5%.

5. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 1, characterized in that: The collimation system comprises a helium-neon laser (61), a plane mirror (62) and a double-sided sensing plate (63); the plane mirror (62) is used for reflecting the light beam emitted by the helium-neon laser (61) onto the double-sided sensing plate (63).

6. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 4, characterized in that: The dispersion compensation system comprises a rotation platform and a prism pair (51); the prism pair (51) is mounted on the rotation platform and is used to perform dispersion adjustment on a light beam passing through a transition end mirror (43) and reflect the light beam to an inductive adjustment system.

7. The solid resonant cavity adjustment device for mid-infrared femtosecond laser generation according to claim 6, characterized in that: The sensing and regulating system comprises a photosensitive plate (11), a beam splitter (12), an adjustable end mirror (13), a charge coupled device (14), an attenuation plate (15), a measuring unit (16), and a control unit (17); a light beam refracted by a prism pair (51) passes through the photosensitive plate (11) and is split into two beams by the beam splitter (12), one beam of which is irradiated onto the charge coupled device (14) through the attenuation plate (15), and the other beam of which is irradiated onto the adjustable end mirror (13); the measuring unit (16) is used to measure the power change of the optical path; the control unit (17) is used to control the operation of the system; the photosensitive plate (11) adopts a 160 μm temperature sensitive photosensitive film; the beam splitter (12) is a polarization-independent beam splitter, and its splitting ratio is set to 80:20, and 80% of the incident light is directed into the cavity to maintain the complex optical process in the cavity; The remaining 20% of the light is split and enters a mid-infrared charge coupled device (14) as detection light for subsequent monitoring and analysis of the optical state in the cavity.

8. A solid resonant cavity adjustment method for mid-infrared femtosecond laser generation, characterized in that: The following steps are involved: Step 1: Build a light source system: configure the light source module (21), select the appropriate wavelength and power; install the isolator module (22) to ensure that the light source is not affected by the reverse beam; install two collimation modules (31) to focus the pump light source on the center of the gain medium (45); Step 2: Build a collimation system to lay the foundation for building a transition cavity system later. To ensure that its height is consistent with the height of the light source system, the helium-neon laser (61) needs to pass through two apertures with the same height as the light source system in sequence. The apertures are placed one far and one near to maintain the linearity of the collimated light source. The double-sided sensing plate (63) is fixed with a clamp and placed on a three-dimensional adjustment frame. It is then placed at a position where the light path of the light source system and the helium-neon laser (61) overlap. The position of the light source on one side is used as a reference to adjust the angle of the plane mirror (62) so that the light sources on both sides overlap in height. Step 3, building a transition cavity system: according to the design parameters, add a plano-concave mirror (41) and adjust its deflection angle to pass through the left and right apertures; place two transition end mirrors (43) respectively according to the helium-neon laser (61); one of the transition end mirrors (43) is used as a transition mirror of the adjustable end mirror (13), and a measurement unit (16) is added after the adjustable end mirror (13) to determine whether the transition cavity resonates; optimize the transition cavity laser, and use the laser transmitted by the transition end mirror (43) as the guide light for building the dispersion compensation system; Step 4: Build a dispersion compensation system: Using the laser light transmitted from the transition end mirror (43) in step 2 as the guide light, place the two prism pairs (51) on a rotating translation stage and adjust them by dislocation; Step 5: Build the sensing and adjustment system: according to the guide light passing through the dispersion compensation system, place the beam splitter, the adjustable end mirror (13), the charge coupled device (14), the attenuation plate (15) and the control unit (17) in sequence; Step 6: Combine the manual mode coarse adjustment with the electric mode fine adjustment to complete the adjustment of the induction adjustment system; Step 7. Careful observation is required during step 6. If the optical paths are highly overlapped in the horizontal and vertical directions, the power of the measuring unit (16) will increase. At this time, the transition end mirror (43) is removed, the prism pair (51) is inserted and the light output adjustment is completed, and the charge coupled device (14) is further optimized for power optimization.

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