A pulse width continuously adjustable ultraviolet laser

Abstract

The utility model relates to the technical field of laser, concretely provides a kind of ultraviolet laser of pulse width continuous adjustable, comprising: infrared laser, green light generating module, delay module, ultraviolet light generating module;Infrared laser generates infrared light;Green light generating module converts part infrared light into green light, and remaining part infrared light and green light are output to delay module;Delay module includes transmission reflector, primary adjustment module, fine adjustment module, first reflector;Transmission reflector reflects input first light, and transmits second light;Primary adjustment module and fine adjustment module are adjusted after the optical path of second light and emit;First reflector reflects second light;Ultraviolet light generating module generates ultraviolet light according to first light and second light.The utility model solves the problem that the adjustment of ultraviolet laser output ultraviolet light pulse in the related art needs to be realized by replacing hardware, and the pulse width adjustment range is limited.

Description

Technical Field

[0001] This utility model relates to the field of laser technology, and in particular to an ultraviolet laser with continuously adjustable pulse width. Background Technology

[0002] In the field of ultraviolet laser applications, the ultraviolet pulse width is a key parameter that determines its suitability for different scenarios. For example, short pulse widths are used for high-precision processing, while long pulse widths are used to improve material removal rates. Therefore, flexible adjustment of the pulse width is crucial for expanding the application scenarios of ultraviolet lasers.

[0003] In related technologies, the pulse width of ultraviolet lasers is usually fixed. If the pulse width of ultraviolet light needs to be adjusted, the corresponding laser needs to be disassembled and replaced or a complex optical cavity needs to be replaced to change the pulse width of the ultraviolet laser. This is not only cumbersome to operate, increasing equipment maintenance costs and downtime, but also prone to damaging the optical path alignment accuracy due to hardware disassembly and assembly, resulting in a decrease in system output stability. Moreover, replacing hardware has low conversion efficiency and insufficient optical path control accuracy, which can easily lead to problems such as nonlinear pulse width adjustment and large fluctuations in output power. It is difficult to meet the requirements of wide range and high linearity pulse width adjustment in high-precision lithography, femtosecond transient carrier research and other scenarios.

[0004] There is currently no effective solution to the problem that adjusting the output ultraviolet light pulse of ultraviolet lasers in related technologies requires hardware replacement and that the pulse width adjustment range is limited. Summary of the Invention

[0005] The present invention provides an ultraviolet laser with continuously adjustable pulse width, which at least solves the problem in the related technology that the adjustment of the output ultraviolet light pulse of ultraviolet lasers needs to be achieved by replacing hardware and that the pulse width adjustment range is limited.

[0006] This invention provides a pulse-width continuously adjustable ultraviolet laser, comprising: an infrared laser 1, a green light generation module 2, a delay module 3, and an ultraviolet light generation module 4; the infrared laser 1 generates infrared light and transmits the infrared light to the green light generation module 2; the green light generation module 2 converts a portion of the input infrared light into green light and outputs the remaining infrared light and the green light to the delay module 3; the delay module 3 includes a transmission mirror 31, a preliminary adjustment module 32, a fine adjustment module 33, and a first mirror 34; the transmission mirror 31 is disposed on the output optical path of the green light generation module 2; the transmission mirror 31 reflects the input first light beam and transmits the second light beam; and transmits the second light beam along the target optical path to the preliminary adjustment module 32; wherein, the first light beam is green light or infrared light, and the... The second ray is infrared light or green light; the initial adjustment module 32 is disposed between the transmission reflector 31 and the first reflector 34, the initial adjustment module 32 performs preliminary adjustment of the optical path of the second ray and inputs the second ray into the fine adjustment module 33; the fine adjustment module 33 is disposed between the initial adjustment module 32 and the first reflector 34, and is used to further adjust the optical path of the second ray before it is emitted; the first reflector 34 is disposed in the output optical path of the fine adjustment module 33, and is used to reflect the output light of the fine adjustment module 33 so that the output light returns from the target optical path to the transmission reflector 31, and passes through the transmission reflector 31 and inputs the first ray into the ultraviolet light generating module 4; the ultraviolet light generating module 4 is used to generate ultraviolet light based on the first ray and the second ray.

[0007] In one embodiment of the present invention, the initial adjustment module 32 includes a first reflective component and a first motor; the first reflective component includes at least two reflectors; the first motor is connected to at least one reflector in the first reflective component; the first motor is used to control the translation of the reflector in the first reflective component to change the transmission optical path of the second light in the first reflective component.

[0008] In one embodiment of the present invention, the delay module 3 further includes an integrated pump laser module 35; the integrated pump laser module 35 is disposed on the input optical path of the initial adjustment module 32; wherein, the input optical path is the optical path through which the green light generating module 2 transmits light to the initial adjustment module 32.

[0009] In one embodiment of the present invention, the fine-tuning module 33 includes an acousto-optic modulator and a second motor; the acousto-optic modulator is disposed on the output optical path of the initial tuning module 32; the second motor is disposed on the first reflector 34, and the second motor is used to control the deflection angle of the first reflector 34.

[0010] In one embodiment of the present invention, the output optical path side and the input optical path side of the acousto-optic modulator are respectively provided with a first waste light processing device 36 and a second waste light processing device 37; the first waste light processing device 36 and the second waste light processing device 37 are used to absorb stray light reflected by the acousto-optic modulator.

[0011] In one embodiment of the present invention, a second reflective component 5 and a third reflective component 6 are further included; the second reflective component 5 is disposed at the intersection of the output optical path of the infrared laser 1 and the input optical path of the green light generating module 2; the third reflective component 6 is disposed at the intersection of the output optical path of the green light generating module 2 and the input optical path of the initial adjustment module 32.

[0012] In one embodiment of the present invention, the delay module 3 further includes a lens group 38, which is disposed on the output optical path of the transmission and reflection mirror 31; the input optical path of the lens group 38 is collinear with the input optical path of the transmission and reflection mirror 31.

[0013] In one embodiment of this utility model, a control component is further included. The control component is connected to the initial adjustment module 32 and the fine adjustment module 33 respectively. The control component is connected to the first motor of the initial adjustment module 32 and is used to control the first motor to adjust the moving distance of the reflector in the first reflection component to change the optical path of the second light. The control component is connected to the second motor of the fine adjustment module 33 and is used to control the second motor to adjust the deflection angle of the first reflector 34.

[0014] In one embodiment of the present invention, the ultraviolet light generating module 4 further includes a detection component; the detection component is connected to the control component; the detection component is disposed at the output port of the ultraviolet light generating module 4; the detection component is used to detect the pulse width and / or energy of the ultraviolet light.

[0015] In one embodiment of this utility model, a third waste light treatment device 7 and an isolator 8 are further included between the infrared laser 1 and the green light generating module 2; the isolator 8 is disposed on the output optical path of the infrared laser 1; and the third waste light treatment device 7 is disposed on the waste light reflection optical path of the isolator 8.

[0016] In one embodiment of this utility model, the ultraviolet light generating module 4 is disposed on the input optical path of the green light generating module 2; the input optical path of the ultraviolet light generating module 4 is collinear with the input optical path of the green light generating module 2; wherein, the ultraviolet light generating module 4 is used to convert the light emitted from the green light generating module 2 into ultraviolet light and emit it.

[0017] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects: After the green light generation module 2 converts part of the infrared light into green light, the delay module 3 separates the infrared light and green light through the transmission and reflection mirror 31. The initial adjustment module 32 and the fine adjustment module 33 increase the optical path of the infrared light to achieve continuous and gradual adjustment of the optical path of the infrared light, so that the phase difference between the infrared light and green light in the time domain is reduced, thereby achieving a smooth transition from the maximum range to the minimum range of the overlap between the infrared light and green light without changing the hardware. The first reflection mirror 34 reflects the delayed infrared light and overlaps it with the green light to the ultraviolet light generation module 4. Since the pulse width of the ultraviolet light generated by the ultraviolet light generation module 4 is equal to the overlap time of the infrared light and green light, the continuous adjustment of the ultraviolet light pulse width can be achieved by continuously controlling the overlap time through the delay module 3. This effectively solves the problem in related technologies that the adjustment of the output ultraviolet light pulse of the ultraviolet laser needs to be achieved by changing the hardware, and the pulse width adjustment range is limited. Attached Figure Description

[0018] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the optical path structure of a pulse-tunable ultraviolet laser device according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram showing the superposition and comparison of the time-domain waveforms of the first ray, the second ray, and the ultraviolet light in an embodiment of this utility model.

[0021] Figure 3 This is a schematic diagram of the structure of a pulse-tunable ultraviolet laser device according to an embodiment of the present invention.

[0022] The above figures include the following reference numerals:

[0023] 1. Infrared laser; 2. Green light generation module; 3. Delay module; 31. Transmission mirror; 32. Initial adjustment module; 33. Fine adjustment module; 34. First mirror; 35. Integrated pump laser module; 36. First waste light treatment device; 37. Second waste light treatment device; 38. Lens group; 4. Ultraviolet light generation module; 5. Second reflection component; 6. Third reflection component; 7. Third waste light treatment device; 8. Isolator; 9. Fourth waste light treatment device. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0027] In related technologies, fixed-pulse-width ultraviolet lasers rely on nonlinear frequency conversion modules with fixed parameters, such as green light generating components and ultraviolet light generating components with specific phase matching, resulting in a fixed output pulse width. If the ultraviolet light pulse width needs to be adjusted, the laser needs to be replaced or the corresponding optical cavity needs to be disassembled and replaced, such as different models of green light generating components, ultraviolet light generating components, pump light adjustment components, etc. This is not only cumbersome to operate, increasing equipment maintenance costs and downtime, but also prone to damaging the optical path alignment accuracy due to hardware disassembly and assembly, leading to a decrease in system output stability.

[0028] Even if some solutions attempt to achieve pulse width adjustment, the lack of a precise delay system prevents the precise control of the optical path difference between infrared and green light to adjust the pulse superposition timing. This results in a limited pulse width adjustment range, which can only be adjusted within a narrow range. Furthermore, there are issues with pulse width jumps and discrepancies during the adjustment process.

[0029] To address the aforementioned problems, this utility model provides a continuously adjustable pulse width ultraviolet laser, which solves the problem that adjusting the output ultraviolet light pulse of the ultraviolet laser in the above-mentioned related technologies requires hardware replacement and that the pulse width adjustment range is limited.

[0030] See Figures 1 to 3As shown, this application provides a pulse width continuously adjustable ultraviolet laser, including: an infrared laser 1, a green light generation module 2, a delay module 3, and an ultraviolet light generation module 4; the delay module 3 is connected to the green light generation module 2 and is used to receive the green light generated by the green light generation module 2, perform delay processing, and then send it back to the ultraviolet light generation module 4.

[0031] Specifically, infrared laser 1 is used to generate infrared light and transmit the infrared light to green light generation module 2; infrared laser 1 provides the basic laser source for ultraviolet laser, and the subsequent generation of green light and ultraviolet light as well as the delay control are all based on the basic laser source. Therefore, stable infrared laser is the key to the continuous adjustment of laser pulse width.

[0032] The wavelength of the infrared light emitted by the infrared laser 1 needs to be matched with the nonlinear crystals of the subsequent ultraviolet light generation module 4 and green light generation module 2 to ensure efficient harmonic generation. For example, if it is necessary to generate 532nm green light through the green light generation module 2 and 355nm ultraviolet light through the ultraviolet light generation module 4, an infrared laser 1 with a wavelength of 1064nm is preferred.

[0033] The pulse width emitted by infrared laser 1 is preferably in the nanosecond range, which can balance energy density and conversion efficiency between ultraviolet and green light. That is, picosecond or femtosecond lasers with pulse widths shorter than nanoseconds require special crystal adaptation, which is costly; microsecond lasers with pulse widths longer than nanoseconds have insufficient energy density.

[0034] Infrared laser 1 may include solid-state infrared laser, fiber infrared laser, gas infrared laser and semiconductor infrared laser, etc. The type of infrared nanosecond laser can be flexibly selected according to specific application requirements (such as processing accuracy, cost budget, wavelength conversion requirements, etc.).

[0035] The green light generation module 2 is used to convert part of the input infrared light into green light and output the remaining infrared light and green light to the delay module 3. The green light generation module 2 mainly converts part of the infrared light into green light through the second harmonic generation effect of the nonlinear crystal.

[0036] The conversion of some infrared light into green light is affected by factors such as the nonlinear coefficient of the nonlinear crystal, light intensity, and phase matching accuracy. Furthermore, some infrared light suffers energy loss due to crystal absorption and lens reflection, preventing it from participating in the conversion. Therefore, even with optimal crystal and optical path parameters, the conversion efficiency of the second harmonic generation effect cannot reach 100%, typically ranging from 50% to 70%. Thus, the green light generation module 2 only converts a portion of the infrared light into green light, outputting the remaining infrared and green light to the delay module 3.

[0037] The aforementioned nonlinear crystals can be KTP (Potassium Titanium Oxide Phosphate) or LBO (Lithium Triborate). The nonlinear crystal needs to be adapted to the infrared wavelength. For example, for 1064nm infrared light, KTP crystals are chosen because they have advantages such as high conversion efficiency and suitability for room temperature operation. LBO crystals are chosen because they have advantages such as high resistance to light damage threshold and suitability for high-power scenarios.

[0038] The second harmonic generation effect is a nonlinear optical effect. Under high-intensity light excitation, the atomic polarization response within a nonlinear crystal generates a second harmonic, which consists of two lower-energy infrared photons that merge into a higher-energy green photon. According to the law of conservation of energy, photon energy is inversely proportional to wavelength; therefore, the wavelength of green light is half that of infrared light. For example, if the input is 1064nm infrared light, the output will be 532nm green light.

[0039] The delay module 3 includes a transmission mirror 31, a preliminary adjustment module 32, a fine adjustment module 33, and a first mirror 34. The transmission mirror 31 is disposed on the output optical path of the green light generation module 2. The transmission mirror 31 is used to reflect the input first light and transmit the second light. The second light is then transmitted to the preliminary adjustment module 32 along the target optical path. The first light is either green light or infrared light, and the second light is either infrared light or green light.

[0040] The transmission-reflection mirror 31 needs to separate the infrared light and green light emitted from the green light generation module 2, passing them through different paths to create an optical path difference between them. This optical path difference, divided by the speed of light, equals the delay time, thus achieving a phase difference between the infrared and green light in the time domain. The optical path difference between the first and second rays creates a relative delay. Assuming the relative delay time ∆t = 0, where ∆t represents the relative delay time between the first and second rays, meaning their pulses completely overlap, the pulse width of the output ultraviolet light is determined by the harmonic average of the input pulse widths. The formula for the output ultraviolet light pulse width is as follows:

[0041]

[0042] in, This indicates the pulse width of the output ultraviolet light. This represents the pulse width at half maximum width of infrared light. This indicates the pulse width at half maximum width of the green light.

[0043] For example ,but T is a hypothetical pulse width.

[0044] When Δt≠0, in this embodiment, the first ray is green light, and the second ray is infrared light. Figure 2As shown in the figure, the horizontal axis represents the time axis of the time-domain waveform, and the vertical axis represents the light intensity amplitude of the time-domain waveform. The green waveform is the time-domain waveform of the first ray, the red waveform is the time-domain waveform of the second ray, and the purple waveform is the time-domain waveform of the ultraviolet light. The delay generated by the delay module 3 on the second ray causes an overlap region between the time-domain waveforms of the first and second rays. The pulse width of the ultraviolet light is determined by the overlap region of the time-domain waveforms of the first and second rays. The actual pulse width of the ultraviolet light is further narrowed, approximated as:

[0045]

[0046] When Δt≫ , When the phase difference between the first and second rays is greater than the pulse width of the infrared and green light, the phases of the first and second rays do not overlap, the ultraviolet pulse disappears, so the relative delay has a maximum value. The maximum optical path difference can be calculated and adjusted based on the maximum relative delay.

[0047] The transmission and reflection mirror 31 can achieve differentiated processing of light of different wavelengths through special optical coating. For example, it can have high transmission for a certain wavelength of light, such as infrared light at 1064nm, i.e., transmittance ≥90%; and high reflection for another wavelength of light, such as green light at 532nm, i.e., reflectance ≥90%.

[0048] The transmission and reflection mirror 31 can transmit infrared light and reflect green light, that is, allow the infrared light to pass through the initial adjustment module 32 and the fine adjustment module 33 and then combine with the green light; it can also transmit green light and reflect infrared light, that is, allow the green light to pass through the initial adjustment module 32 and the fine adjustment module 33 and then combine with the infrared light.

[0049] Both the initial adjustment module 32 and the fine adjustment module 33 are used to increase the optical path of the input second ray before it is emitted. The initial adjustment module 32 increases the geometric distance of the beam transmission path over a wide range, achieving initial adjustment of the optical path difference. The fine adjustment module 33 features fast response speed and high precision, enabling rapid, small-range fine adjustment of the optical path difference after the initial adjustment. The initial adjustment module 32 has a large adjustment range, while the fine adjustment module 33 adjusts minute optical path differences. The combination of the initial adjustment module 32 and the fine adjustment module 33 enables optical path control with wide coverage and high-precision fine adjustment.

[0050] The initial adjustment module 32 is located between the transmission mirror 31 and the first mirror 34. The initial adjustment module 32 performs preliminary adjustment on the optical path of the second light and inputs the second light into the fine adjustment module 33. The adjustable delay line changes the optical path by means of the mechanical structure. Its adjustment range is determined by the mechanical stroke or angle range and can be on the order of nanometers to centimeters.

[0051] The initial adjustment module 32 can be composed of multiple sets of reflectors. The first motor controls the spacing between the reflector sets, thereby changing the propagation path length of light between the mirror sets. Alternatively, the motor can control the tilt angle of the reflectors to change the reflection path length of light, and the optical path difference is indirectly determined by the change in the angle of the reflectors. Alternatively, optical fiber can be used as the transmission medium, and the motor controls the winding and unwinding of the optical fiber, such as winding it around a rotatable axle, and the optical path difference is adjusted by the change in the length of the optical fiber.

[0052] The fine-tuning module 33 is positioned between the initial-tuning module 32 and the first reflecting mirror 34 to further adjust the optical path of the second light beam before it is emitted. In this embodiment, the fine-tuning module 33 preferably uses an acousto-optic modulator to change the deflection angle of the diffracted light. Combined with the position adjustment of the first reflecting mirror 34, dynamic adjustment of the optical path can be achieved. The acousto-optic modulator is based on the acousto-optic effect, which drives the crystal refractive index to change through sound waves, thereby changing the propagation path of the light. The adjustment range is determined by the sound wave frequency range and the crystal length, and can be in the sub-nanometer to nanometer range.

[0053] The first reflector 34 is disposed on the output optical path of the fine adjustment module 33. The first reflector 34 is used to reflect the output light of the fine adjustment module 33 so that the output light returns from the target optical path to the transmission reflector 31 and passes through the transmission reflector 31 to the first light input ultraviolet light generation module 4.

[0054] The first reflector 34 is a reflector that can achieve precise control of angle deflection, tilting or position translation. By adjusting the angle and position, the first reflector 34 compensates for the different deflection angles and positions of the second light rays after adjustment by different initial adjustment modules, ensuring that the light path returned through the first reflector 34 is the same as the original light path.

[0055] The first reflecting mirror 34 can be a motor-driven reflecting mirror for angle compensation, or it can be a piezoelectric ceramic reflecting mirror. In this embodiment, a motor-driven reflecting mirror is preferred for angle compensation, offering high-speed dynamic response, high-precision angle adjustment, and a wide-range compensation capability. The wide angle adjustment range can adapt to different amplitude angle fluctuations and meet fine-tuning correction requirements, while the millisecond-level response speed matches the timeliness of dynamic optical path adjustment.

[0056] The ultraviolet light generation module 4 is used to generate ultraviolet light based on the first and second light rays. The ultraviolet light generation module 4 mainly uses a nonlinear crystal to perform a third harmonic generation effect to cut the first light ray (such as 532nm green light) and the second light ray (such as 1064nm infrared light) at a 355nm phase matching angle to generate and output 355nm ultraviolet light.

[0057] Phase-matched cutting refers to the process of cutting the nonlinear crystal at a specific angle during the sum-frequency effect to ensure that the first and second rays and the generated 355nm ultraviolet light satisfy the conservation of momentum within the crystal, thus avoiding photon cancellation.

[0058] The aforementioned nonlinear crystals can include CLBO (Cesium Lithium Borate), LBO (Lithium Triborate), and BBO (Beta-Barium Borate). CLBO mixes 1064nm infrared light with 532nm green light to generate 355nm ultraviolet light. BBO converts 532nm green light into 266nm ultraviolet light; LBO has a wide transmission range and is often used for frequency third-harmonic generation of 1064nm lasers to 355nm.

[0059] The third harmonic generation effect refers to the conversion of the first and second light rays into ultraviolet light through the sum-frequency effect. The sum-frequency effect refers to the meeting of two incident photons, namely a 1064nm infrared photon and a 532nm green photon, in a nonlinear crystal, and their merging into a new photon under high-intensity excitation. According to the law of conservation of energy, the frequency of the new photon is equal to the sum of the frequencies of the original photons. Substituting the corresponding wavelengths of 1064nm and 532nm, we obtain 355nm ultraviolet light.

[0060] This scheme utilizes delay module 3 to control the relative delay (Δt) between infrared and green light pulses, thereby achieving an effective method for continuously adjustable ultraviolet laser pulse width during the sum-frequency effect generation process. The scheme has a clear structure, with its core lying in high-precision delay control technology and fine-tuning of spatiotemporal overlap. The ultraviolet laser pulse width output by the system can be continuously and precisely adjusted within the design range, providing a powerful technical means for ultraviolet light sources requiring flexible pulse width parameters in scientific research and industrial applications.

[0061] The key to successful implementation lies in the phase matching control of the high-precision delay module 3, the stable infrared laser 1, the high-quality transmission and reflection mirror 31, and the green light generation module 2 and the ultraviolet light generation module 4. By utilizing the optical path difference between infrared and green light, the infrared pulse is delayed, creating a phase difference with the green light in the time domain. This reduces the time overlap between the infrared and green light, and the pulse width of the ultraviolet light generated after summing is approximately equal to the overlap time of the infrared and green light. This overlap time is controlled by the adjustable optical path difference.

[0062] In summary, in this embodiment, after the green light generating module 2 converts part of the infrared light into green light, the delay module 3 separates the infrared light and green light through the transmission and reflection mirror 31. The initial adjustment module 32 and the fine adjustment module 33 increase the optical path of the infrared light to achieve continuous and gradual adjustment of the optical path of the infrared light, so as to make the phase difference between the infrared light and the green light in the time domain smooth from the maximum range to the minimum range without changing the hardware equipment.

[0063] The first reflector 34 reflects the delayed infrared light and overlaps it with the green light to the ultraviolet light generating module 4. The ultraviolet light pulse width generated by the ultraviolet light generating module 4 is equal to the overlap time of the infrared light and the green light.

[0064] Therefore, by continuously adjusting the overlap time through delay module 3, the pulse width of the ultraviolet light can be continuously adjusted. This effectively solves the problem in related technologies where adjusting the output ultraviolet light pulse of an ultraviolet laser requires hardware replacement and the pulse width adjustment range is limited.

[0065] In one embodiment of the present invention, the initial adjustment module 32 includes a first reflective component and a first motor; the first reflective component includes at least two reflectors; the first motor is connected to at least one reflector in the first reflective component; the first motor is used to control the translation of the reflector in the first reflective component to change the transmission optical path of the second light in the first reflective component.

[0066] The initial adjustment module 32 uses a first motor to change the mechanical structure of the reflective component, thereby changing the optical path. The first reflective component includes at least two reflectors. The first motor can control the movement of at least one reflector to change the optical path, and the first motor can also control multiple reflectors to change the optical path.

[0067] The first motor can change the optical path by translating the reflector. Due to the round-trip propagation of light, the optical path difference changes by twice the translation distance of the reflector. For example, if the translation stage travels 1 cm, the optical path difference can be adjusted up to 2 cm. Since the optical path is equal to the distance multiplied by the refractive index, and the air refractive index is approximately 1, the optical path difference is about 66.7 nm. If the travel is 10 cm, the optical path difference can be adjusted up to 20 cm, corresponding to an optical path difference of about 667 nm.

[0068] The first reflecting component can also consist of multiple sets of mirrors. A first motor controls the spacing between the mirror sets, thereby changing the path length of light propagation between the mirror sets. Compared to the translation of a single mirror, the multi-mirror structure allows for large optical path adjustment within a small space. If multiple mirrors achieve n reflections, with the same change in mirror spacing, the change in optical path difference is 2n times the change in spacing, where n can be increased by designing multiple mirrors.

[0069] The first motor can also change the optical path by controlling the tilt angle of the reflector. When the reflector rotates around its axis, the angle of incidence of the light changes, and the path length of the reflected light is converted into a change in the optical path difference through trigonometric functions. When the optical path difference is increased, the first motor controls the reflector to rotate in the direction that increases the optical path, allowing the light to travel further after reflection. When the optical path difference is decreased, the first motor controls the reflector to rotate in the direction that decreases the optical path, allowing the light to travel shorter after reflection.

[0070] The first motor can be a stepper motor that controls the rotor to rotate step by step through pulse signals, converting angular displacement into linear displacement; it can also be a closed-loop control motor with position feedback such as an encoder, which can correct displacement errors in real time; or it can utilize the inverse piezoelectric effect of piezoelectric materials to generate small deformations, and achieve linear drive through friction or creep.

[0071] In summary, the first motor in the initial adjustment module 32 converts mechanical displacement into optical path change through the transmission structure, realizing optical path adjustment from nanometer to centimeter level, meeting the wide range of requirements in pulse width adjustment, and ensuring that the fine adjustment module 33 only needs to process nanometer-level residuals, thus avoiding the fine adjustment range being occupied.

[0072] In one embodiment of this utility model, the delay module 3 further includes an integrated pump laser module 35; the integrated pump laser module 35 is disposed on the input optical path of the initial adjustment module 32; wherein, the input optical path is the optical path through which the green light generating module 2 transmits light to the initial adjustment module 32.

[0073] The integrated pump laser module 35 is a module that enhances laser energy by coupling the pump light with the signal light to supplement the energy of the transmitted second light beam.

[0074] The second light beam experiences energy loss during its round-trip path through the delay module 3, such as via the transmission and reflection mirror 31, the initial adjustment module 32, and the fine adjustment module 33. The integrated pump laser module 35 replenishes the laser energy in real time, ensuring that the laser entering the ultraviolet light generation module 4 has sufficient power, thereby guaranteeing the output energy and pulse width adjustment range of the ultraviolet light, while compensating for the energy loss during optical path adjustment.

[0075] The integrated pumped laser module 35 can be a semiconductor pumped module, such as an 808nm semiconductor laser, which combines with the second beam through an optical fiber or optical coupling element to replenish energy to the laser gain medium. When the second beam passes through the laser gain medium in a population-inverted state, stimulated emission is induced, thereby amplifying the energy of the second beam through superposition.

[0076] The integrated pumped laser module 35 can also be an all-solid-state pumped module, which integrates the pump source, coupling lens and laser gain medium to directly amplify the energy of the transmitted laser in the online manner, and is suitable for highly integrated laser systems.

[0077] In one embodiment of the present invention, the fine-tuning module 33 includes an acousto-optic modulator and a second motor; the acousto-optic modulator is disposed on the output optical path of the initial tuning module 32; the second motor is disposed on the first reflector 34 and is used to control the deflection angle of the first reflector 34.

[0078] An acousto-optic modulator uses a radio frequency (RF) signal to drive a piezoelectric transducer to form an acoustic grating in a crystal. Incident light undergoes Bragg diffraction on the grating. That is, changing the RF signal frequency can adjust the wavelength of the grating, thereby changing the deflection angle of the diffracted light. Combined with precise control of the light propagation path length and the path difference of the diffraction order, rapid, inertia-free tuning of the optical delay can be achieved.

[0079] The second ray passes through the acousto-optic modulator twice. The first time, the 0th-order light directly transmitted through the modulator is unreflected, belonging to the 0th-order diffraction. The second time, the light beam, after diffraction by the modulator, is deflected in one direction, belonging to the 1st-order diffraction. The 1st-order light is the signal light to be used after passing through the modulator; it can exit to the first reflecting mirror 34 and return.

[0080] During the second pass, the beam of light, after being diffracted by the acousto-optic modulator, is deflected in the opposite direction, corresponding to the -1 secondary order in the grating equation. The -1 order light is symmetrical to the +1 order light. The -1 order light diffracted by the acousto-optic modulator is reflected by the first reflecting mirror 34 and returns along the original optical path, so that the -1 order light returns to the transmission reflecting mirror 31.

[0081] When the acousto-optic modulator is driven at different frequencies, the deflection angle of the first-order light will change. This difference can be compensated by controlling the angle of the first reflector 34, ensuring that the reflected light path is consistent with the original light path, and ensuring that the second light ray returns to the original path stably and accurately, and is converted into ultraviolet light by frequency conversion with the first light ray.

[0082] The different angles at which the first-order light reaches the first reflector 34 result in differences in the optical path of the first-order light reaching the first reflector 34. The optical path of the second ray includes the optical path of the first-order light. Therefore, the optical path difference of the second ray can be changed by using an acousto-optic modulator to change the deflection angle of the first-order light.

[0083] The aforementioned acousto-optic modulator can achieve optical path control via electrical signals without the need for hardware replacement or disassembly, and its response time can reach the nanosecond level. This enables rapid and continuous adjustment of the optical path, allowing for more precise and rapid continuous adjustment of the second light beam. Continuous adjustment of the optical path difference allows for continuous adjustment of the delay difference between the second and first light beams, and this delay difference can further meet the requirement of continuously adjustable pulse width.

[0084] The diffraction angle of the acousto-optic modulator is directly related to the driving frequency. When the driving frequency of the acousto-optic modulator is changed, the deflection angle of the first-order diffracted light it produces will change. If the angle of the first reflecting mirror is fixed at 34°, the returned light will deviate from the original path, causing the beams in subsequent optical paths to not be precisely aligned, affecting the ultraviolet pulse width modulation and output quality.

[0085] The purpose of setting up the second motor is to dynamically compensate for changes in the diffraction angle, ensuring that the light returned by the first reflector 34 is completely consistent with the original path, guaranteeing the optical path length and alignment accuracy of the second light beam's outward and return journeys, and ultimately achieving stable adjustment of the laser pulse width. Through the dynamic angle adjustment of the second motor, it is ensured that the first-order and -1st-order light beams passing through the acousto-optic modulator twice are completely overlapped in space, providing a stable optical path foundation for subsequent pulse width adjustment and ultraviolet light generation.

[0086] The diffraction angle formula for an acousto-optic modulator satisfies sinθ= λ is the laser wavelength, f is the driving frequency, and v is the ultrasonic speed. When f changes, the diffraction angle θ changes accordingly, and the deflection angle of the first-order light also changes. The control component sends a command to the second motor according to the driving frequency of the acousto-optic modulator to adjust the deflection angle of the first reflector 34, compensating for the change in the diffraction angle so that the reflected light returns along the original path, that is, satisfying the condition that the incident angle equals the reflection angle.

[0087] The second motor controlling the first reflector 34 needs to be characterized by high precision, fast response, and strong stability. A servo motor with a high-precision encoder can be used, providing real-time feedback of the angle of the first reflector 34 via a photoelectric encoder. The angle adjustment precision can reach the micro-radian level, enabling rapid response to diffraction angle fluctuations caused by changes in the frequency of the acousto-optic modulator. Alternatively, a piezoelectric second motor can be used, achieving nanometer-level precision angle fine-tuning based on the piezoelectric effect. This eliminates mechanical friction, achieves a microsecond-level response speed, and can accurately compensate for small-range diffraction angle changes.

[0088] In one embodiment of the present invention, a first waste light processing device 36 and a second waste light processing device 37 are respectively provided on the output optical path side and the input optical path side of the acousto-optic modulator; the first waste light processing device 36 and the second waste light processing device 37 are used to absorb stray light reflected by the acousto-optic modulator.

[0089] When the second light beam passes through the acousto-optic modulator, it generates multi-order diffraction light (such as 0th-order light, 1st-order light, -1st-order light, etc.). Among them, the 1st-order light and -1st-order light are the effective light used in subsequent optical paths. If the unused 0th-order light propagates in the system, it will form stray light, which will interfere with the transmission of effective light and affect the accuracy of laser pulse width modulation and the quality of the output beam.

[0090] The first waste light treatment device 36 is used to absorb the 0th-order light that passes through the acousto-optic modulator for the first time but is not deflected. After the 1st-order light returns through the first reflector 34, it will diffract when it passes through the acousto-optic modulator for the second time. At this time, the original 1st-order light will be diffracted into -1st-order light and then return. The residual 1st-order light that is not deflected when it passes through the acousto-optic modulator for the second time is absorbed by the second waste light treatment device 37.

[0091] The first waste light treatment device 36 and the second waste light treatment device 37 are based on the principle of light absorption. They convert the light energy of waste light into heat energy through materials or structures with high absorption rates, thereby completely dissipating the energy of stray light and preventing it from propagating in the system. The first waste light treatment device 36 and the second waste light treatment device 37 can be laser absorbers or extinction devices.

[0092] The first waste light treatment device 36 and the second waste light treatment device 37 need to be precisely positioned on the emission path of the waste light, and the angle of the waste light treatment device should match the emission angle of the waste light to ensure that all the waste light enters the device and can be directly incident into the device, avoiding scattering or reflection of the waste light before it reaches the treatment device, which would affect the absorption effect.

[0093] At the same time, the first waste light treatment device 36 and the second waste light treatment device 37 should also maintain a sufficient spatial distance from the effective light path to avoid interference of the waste light treatment device with the transmission of effective light, and also to prevent effective light from accidentally entering the waste light treatment device and causing energy loss.

[0094] In one embodiment of the present invention, a second reflective component 5 and a third reflective component 6 are further included; the second reflective component 5 is disposed at the intersection of the output optical path of the infrared laser 1 and the input optical path of the green light generating module 2; the third reflective component 6 is disposed at the intersection of the output optical path of the green light generating module 2 and the input optical path of the initial adjustment module 32.

[0095] The core function of the second reflective component 5 is to change the direction of the optical path, realizing the transition and coupling of the optical path from the output optical path of the infrared laser 1 to the input optical path of the green light generating module 2. The function of the third reflective component 6 is to change the direction of the optical path, realizing the transition and coupling of the optical path from the output optical path of the green light generating module 2 to the input optical path of the initial adjustment module 32.

[0096] The output and input optical paths of the target optical path may have angular deviations due to equipment installation location and space limitations, such as perpendicular intersection or non-collinearity. The second reflective component 5 and the third reflective component 6 change the propagation direction of the light through reflection, so that the input light accurately enters the target optical path, avoiding spatial layout conflicts caused by direct light path and improving the space utilization of the system.

[0097] The second and third reflective components 5 and 6 can flexibly change the direction of the light path through one or more reflections (which may include multiple reflectors), allowing the light to enter the target light path with the shortest path and the best angle, thus balancing spatial layout and optical performance. Furthermore, the second and third reflective components 5 and 6 can precisely control the reflection direction of the output light by adjusting their angles, improving the coupling efficiency between the light and each module and reducing energy loss.

[0098] The second reflective component 5 and the third reflective component 6 can be high-reflectivity lenses, such as metal film reflectors or dielectric film reflectors, designed for 1064nm infrared light wavelengths, with a reflectivity greater than 99%, ensuring efficient reflection of infrared light.

[0099] The second reflective component 5 and the third reflective component 6 may also include filters. If stray light exists in the optical path, a bandpass filter can be integrated to allow only the target infrared wavelength to pass through, thereby further purifying the light beam.

[0100] The second reflective component 5 and the third reflective component 6 may also include a polarizer. If the green light generating module 2 has requirements for the polarization state of the incident light, such as linearly polarized light, a polarizer can be added so that the infrared light reflected by the reflective components meets the polarization state requirements.

[0101] The second reflective assembly 5 and the third reflective assembly 6 may also include a fine-tuning frame for fixing the precision mechanical structure of the mirrors in the first reflective assembly and the second reflective assembly, supporting angle fine-tuning, such as pitch and yaw adjustment, for fine alignment of the optical path.

[0102] In one embodiment of the present invention, the delay module 3 further includes a lens group 38, which is disposed on the output optical path of the transmission and reflection mirror 31; the input optical path of the lens group 38 is collinear with the input optical path of the transmission and reflection mirror 31.

[0103] The transmission mirror 31 splits the light output from the green light generation module 2. The transmitted second ray may have parameters that deviate from the requirements of the initial adjustment module 32 and the fine adjustment module 33, which needs to be corrected by the lens group 38. The lens group 38 is collinear with the input light path of the transmission mirror 31, which can ensure that the beam is controlled in the same straight line direction, avoid the alignment difficulties of subsequent modules due to light path deviation, and simplify the system debugging difficulty.

[0104] In the transmission optical path from the transmission mirror 31 to the initial adjustment module, the second ray may diverge due to diffraction and scattering. The lens can focus or collimate the beam, ensuring that the laser beam entering the initial adjustment module has good parallelism or focusing characteristics, thereby improving the accuracy of optical path adjustment and ensuring the effective function of the subsequent initial adjustment module 32 and fine adjustment module 33, while avoiding energy loss or optical path deviation caused by beam divergence.

[0105] The lens can be a focusing lens, composed of a single or multiple convex lenses, such as a cemented doublet convex lens, which can be used to focus a parallel beam into a small spot and focus the second light beam onto the working area of ​​the initial adjustment module 32, thereby improving the working efficiency of the second light beam and the initial adjustment module 32.

[0106] Alternatively, a collimating lens can be selected, which is a combination of a convex lens (such as a biconvex lens) and a concave lens. For example, an achromatic collimating lens can convert diverging or converging beams into parallel beams and convert diverging second rays into parallel light, ensuring the stability of the beam propagation direction during optical path adjustment.

[0107] In one embodiment of the present invention, a control component is further included. The control component is connected to the initial adjustment module 32 and the fine adjustment module 33 respectively. The control component is connected to the first motor of the initial adjustment module 32 and is used to control the first motor to adjust the moving distance of the reflector in the first reflection component. The control component is connected to the second motor of the fine adjustment module 33 and is used to control the second motor to adjust the deflection angle of the first reflector 34.

[0108] The first and second motors can be linked with the control components via digital signals, such as pulses or RS485 protocols, to achieve automatic adjustment of the optical path, such as real-time correction of the optical path based on interference signal feedback, thereby improving the intelligence level of the system.

[0109] The control component sends a control signal to the first motor in the initial adjustment module 32, thereby controlling the mirror in the first reflection component to translate and adjust the optical path to near the target value within the accuracy range, thus achieving the initial adjustment of the optical path of the second ray. The large optical path adjustment of the first motor can quickly change the optical path while avoiding overload of the fine adjustment module 33 due to insufficient adjustment range.

[0110] The pulse width of the ultraviolet laser is determined by the optical path difference between the first and second rays. The greater the optical path difference, the smaller the phase difference between the first and second rays when they are superimposed in the ultraviolet light generation module 4, and the shorter the pulse width of the output ultraviolet light; conversely, the smaller the optical path difference, the longer the pulse width.

[0111] The fine-tuning module 33 requires nanometer- or micrometer-level precision, which is difficult to achieve manually. The control component drives the acousto-optic modulator in the fine-tuning module 33 through electrical signals, which can achieve high-precision and repeatable optical path control, avoid the errors and drift of mechanical adjustment, and ensure the stability of the laser pulse width.

[0112] The laser pulse width needs to be adjusted in real time according to the scenario, such as the different pulse width requirements for different materials in material processing. The control component can receive the pulse width of the ultraviolet light set by the user or the time delay of the first light beam relative to the second light beam. According to the target set value, the control component precisely controls the optical path adjustment of the second light beam, realizing continuous and precise adjustment of the time delay. That is, under this adjustment method, the ultraviolet laser can continuously adjust the ultraviolet pulse width without replacing the hardware. The user only needs to input a signal through software to control the optical path of the second light beam to achieve the delay of the first light beam relative to the second light beam.

[0113] When the control component receives an external control signal, it converts it into a target value for optical path adjustment, including the drive value of the first motor in the initial adjustment module 32, the radio frequency frequency of the acousto-optic modulator, and the drive value of the second motor. Based on the target value, it outputs drive signals, such as radio frequency signals or electrical signals, to the initial adjustment module 32 and the fine adjustment module 33, causing the first motor, the acousto-optic modulator, and the second motor to perform optical path adjustment.

[0114] The first motor drives the reflector in the first reflective assembly to initially change the optical path of the second light ray; the acousto-optic modulator changes the diffraction angle of the second light ray through radio frequency signals to finely adjust the optical path; the second motor moves the first reflector 34 to compensate for the diffraction angle of the second light ray so that the light ray returns along its original path.

[0115] In one embodiment of the present invention, the ultraviolet light generating module 4 further includes a detection component; the detection component is connected to the control component; the detection component is disposed at the output port of the ultraviolet light generating module 4; the detection component is used to detect the pulse width and / or energy of the ultraviolet light.

[0116] During operation, the ultraviolet laser may experience deviations in pulse width or energy output from the set values ​​due to environmental changes or module errors, such as frequency shifts in the acousto-optic modulator or displacement deviations in the translation stage. A detection component is located at the output port of the ultraviolet light generation module 4 to monitor output parameters in real time. The detection component is connected to the control component, which receives feedback signals from the actual optical path length, compares them with the target value, and corrects the drive signal to ensure the accuracy of the initial adjustment module 32 and the fine adjustment module 33.

[0117] In industrial processing or scientific research applications of ultraviolet lasers, the pulse width and energy stability of the ultraviolet light directly affect processing accuracy or experimental results. The detection component can capture parameter fluctuations in real time and dynamically adjust the optical path by controlling the component, ensuring the consistency of laser parameters during long-term operation.

[0118] At the output port of the ultraviolet light generation module 4, a small amount of ultraviolet light is intercepted using optical elements, such as a beam splitter, without affecting the main optical path output, and used as a detection sample. A dedicated sensor converts the pulse width and energy of the ultraviolet light into electrical signals, respectively. The pulse width corresponds to the duration of the electrical signal, and the energy corresponds to the amplitude of the electrical signal.

[0119] The processed electrical signal is transmitted to the control component and compared with the electrical signal of the preset target pulse width or energy parameter. If there is a deviation between the detected value and the target value, the control component can adjust the parameters of the initial adjustment module 32 and the fine adjustment module 33, namely the displacement of the first reflector, the deflection of the first reflector 34, and the radio frequency of the acousto-optic modulator, until the detected value returns to the target range.

[0120] The detection component can integrate a fast photodetector for monitoring the energy of the ultraviolet pulse. Since the energy also changes with time delay, monitoring the ultraviolet pulse energy can also provide information on the adjustment of the delay module 3. The detection component can also use an autocorrelation / cross-correlation meter to monitor the pulse width in real time, forming a closed-loop control to improve stability.

[0121] In one embodiment of this utility model, a third waste light processing device 7 and an isolator 8 are further included between the infrared laser 1 and the green light generating module 2; the isolator 8 is disposed on the output optical path of the infrared laser 1; the third waste light processing device 7 is disposed on the waste light reflection optical path of the isolator 8.

[0122] Isolator 8 is a unidirectional optical element that allows laser light to propagate in only one direction, preventing backlight, such as reflected light and stray light, from returning to the light source. In this embodiment, isolator 8 is located at the output end of infrared laser 1, allowing infrared light to propagate only in the output direction of infrared laser 1, and preventing reflected light and stray light from returning to the light source.

[0123] The infrared light generated by infrared laser 1 needs to be stably transmitted to green light generating module 2. If there is backlight in the optical path, such as reflected light from green light generating module 2 or backlight from optical elements, it will interfere with the working stability of infrared laser 1 after returning, causing laser mode switching, power fluctuations, or even damage to the laser medium. Isolator 8 can completely block backlight, ensuring unidirectional transmission of infrared light and guaranteeing the output stability and lifespan of the laser.

[0124] The isolator 8 can be a Faraday optical isolator, a free-space optical isolator, a two-stage optical isolator, or a polarization-independent optical isolator. The preferred Faraday optical isolator in this embodiment is based on the Faraday magneto-optical effect, effectively preventing backlight from returning to the infrared laser 1 and ensuring stable laser operation. It is suitable for various wavelengths, including the infrared band, and offers high isolation, exceeding 30 dB.

[0125] The third waste light treatment device 7 is a component that absorbs the reverse waste light or stray light generated by the isolator 8. When the isolator 8 blocks the reverse light, it may generate a small amount of stray light. If this waste light is not treated, it will propagate in the optical path and interfere with other modules. The third waste light treatment device 7 can directionally absorb this waste light, avoid stray light interference, and ensure the optical purity of the system.

[0126] The third waste light treatment device 7 can employ a laser absorber, which is made of high-absorption materials (such as black anodized aluminum, silicon carbide ceramics, etc.) and designed as a conical or nested structure, so that the waste light is reflected multiple times inside and completely absorbed. It is suitable for treating low-power stray light generated by the isolator 8. Alternatively, an extinction device can be used, which is coated with a high extinction ratio coating with an absorptivity greater than 99%. It directly absorbs the incident waste light, has a compact structure, and is suitable for waste light treatment scenarios with small angles and low power.

[0127] In summary, isolator 8 ensures stable unidirectional transmission of infrared light and prevents reverse light from damaging the laser; the third waste light treatment device 7 absorbs stray light generated by isolator 8 and eliminates optical interference. Together, they improve the stability and purity of the infrared light transmission path, laying the foundation for subsequent green light generation and ultraviolet light output.

[0128] In one embodiment of this utility model, the ultraviolet light generating module 4 is disposed on the input optical path of the green light generating module 2; the input optical path of the ultraviolet light generating module 4 is collinear with the input optical path of the green light generating module 2; wherein, the ultraviolet light generating module 4 is used to convert the light emitted by the green light generating module 2 into ultraviolet light and emit it.

[0129] The ultraviolet light generating module 4 receives the second beam and the first beam after the optical path difference has been adjusted by the delay module 3. It mixes the second and first beams and integrates their energy through specific optical effects, such as frequency doubling and sum-frequency conversion, to generate ultraviolet light that meets the power and pulse width requirements. Simultaneously, during wavelength conversion, the ultraviolet light generating module 4 maintains the optical path difference characteristic controlled by the delay module 3, ensuring that the pulse width of the output ultraviolet light matches the preset value, thus achieving the ultimate goal of continuously adjustable pulse width.

[0130] The ultraviolet light generating module 4 includes a nonlinear crystal that converts green light into ultraviolet light through nonlinear optical effects. The nonlinear crystal can be selected according to the conversion method, such as an LBO for third harmonics or a BBO for fourth harmonics.

[0131] The ultraviolet light generating module 4 also includes a fourth waste light treatment device 9, which is located at the output end of the ultraviolet light generating module 4. The stray light is directed to the fourth waste light treatment device 9 through a beam splitter. It is used to separate and process the stray light such as green light and infrared light remaining in the conversion process of the ultraviolet light generating module 4, so as to ensure the purity of the output ultraviolet light and avoid the waste light from affecting the equipment or personnel.

[0132] The conversion efficiency of nonlinear crystals is extremely sensitive to temperature. For example, a temperature deviation of 0.1℃ may cause a significant drop in efficiency. The ultraviolet light generation module 4 can be equipped with a temperature controller, such as a hermoelectric cooler (TEC), and a temperature sensor to stabilize the crystal temperature at the optimal operating point.

[0133] The ultraviolet light generating module 4 may also include beam focusing or collimating elements, such as focusing lenses or collimating mirrors, to focus the incident first beam and second beam onto the center of the crystal, thereby increasing the light intensity density and ensuring the beam quality of the emitted ultraviolet light.

[0134] The input optical path of the ultraviolet light generating module 4 is collinear with the input optical path of the green light generating module 2, which means that the first and second beams after being reflected and adjusted by the delay module 3 can directly enter the module along the original optical path without additional reflection and deflection, thus avoiding energy loss and beam deviation caused by multiple reflections.

[0135] The optical path difference between the two light sources is formed in the path from the green light generation module 2 to the delay module 3 and then to the ultraviolet light generation module 4. The collinear layout of the input optical path of the ultraviolet light generation module 4 and the input optical path of the green light generation module 2 ensures that the optical path difference does not change during transmission and directly affects the wavelength conversion in the crystal, thus ensuring the accuracy and stability of the ultraviolet light pulse width.

[0136] The infrared light output from the infrared laser to the ultraviolet light generation module 4 does not produce ultraviolet light, while the first and second rays returning from the delay module 3 along the green light generation module 2 are converted into ultraviolet light. The core of the ultraviolet light generation module 4 is a nonlinear crystal (such as LBO, BBO, etc.), and the sum-frequency effect for generating ultraviolet light has strict triggering conditions.

[0137] The aforementioned triggering conditions require the simultaneous action of two different wavelengths of light, and the propagation speeds of the two incident lights within the crystal must be matched to ensure the continuous superposition of sum-frequency light energy. In this embodiment, the sum-frequency condition is only satisfied when green light and infrared light are simultaneously incident on the nonlinear crystal. That is, after the second light enters the delay module 3 for adjustment, it simultaneously enters the ultraviolet light generation module 4 with the first light, at which point the ultraviolet light generation module 4 activates to generate and output ultraviolet light.

[0138] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0139] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0140] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A continuously adjustable pulse width ultraviolet laser, characterized in that, include: Infrared laser (1), green light generating module (2), delay module (3), ultraviolet light generating module (4); The infrared laser (1) is used to generate infrared light and transmit the infrared light to the green light generating module (2). The green light generating module (2) is used to convert part of the input infrared light into green light and output the remaining part of the infrared light and the green light to the delay module (3). The delay module (3) includes a transmission mirror (31), a preliminary adjustment module (32), a fine adjustment module (33), and a first mirror (34); the transmission mirror (31) is disposed on the output optical path of the green light generation module (2); the transmission mirror (31) is used to reflect the input first light and transmit the second light; and transmit the second light along the target optical path to the preliminary adjustment module (32); wherein, the first light is green light or infrared light, and the second light is infrared light or green light; The initial adjustment module (32) is located between the transmission mirror (31) and the first mirror (34). The initial adjustment module (32) performs preliminary adjustment on the optical path of the second light and inputs the second light into the fine adjustment module (33). The fine-tuning module (33) is disposed between the initial tuning module (32) and the first reflector (34) for further adjusting the optical path of the second light before it is emitted; the first reflector (34) is disposed in the output optical path of the fine-tuning module (33) and is used to reflect the output light of the fine-tuning module (33) so that the output light returns from the target optical path to the transmission reflector (31) and passes through the transmission reflector (31) and the first light is input into the ultraviolet light generating module (4). The ultraviolet light generating module (4) is used to generate ultraviolet light based on the first light and the second light.

2. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The initial adjustment module (32) includes a first reflective component and a first motor; the first reflective component includes at least two reflectors; The first motor is connected to at least one reflector in the first reflective assembly; The first motor is used to control the translation of the reflector in the first reflective assembly to change the transmission optical path of the second light in the first reflective assembly.

3. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The delay module (3) also includes an integrated pumped laser module (35); The integrated pump laser module (35) is disposed on the input optical path of the pre-tuning module (32); wherein, the input optical path is the optical path from the green light generating module (2) to the pre-tuning module (32).

4. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The fine-tuning module (33) includes an acousto-optic modulator and a second motor; The acousto-optic modulator is disposed on the output optical path of the pre-tuning module (32); The second motor is mounted on the first reflector (34) and is used to control the deflection angle of the first reflector (34).

5. The ultraviolet laser with continuously adjustable pulse width according to claim 4, characterized in that, The output optical path side and the input optical path side of the acousto-optic modulator are respectively provided with a first waste light treatment device (36) and a second waste light treatment device (37). The first waste light treatment device (36) and the second waste light treatment device (37) are used to absorb stray light reflected by the acousto-optic modulator.

6. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, It also includes a second reflective component (5) and a third reflective component (6); The second reflective component (5) is located at the intersection of the output optical path of the infrared laser (1) and the input optical path of the green light generating module (2); The third reflection component (6) is located at the intersection of the output optical path of the green light generating module (2) and the input optical path of the initial adjustment module (32).

7. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The delay module (3) also includes a lens group (38), which is disposed in the output optical path of the transmission and reflection mirror (31); The input optical path of the lens group (38) is collinear with the input optical path of the transmission mirror (31).

8. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, It also includes a control component, which is connected to the initial adjustment module (32) and the fine adjustment module (33) respectively; The control component is connected to the first motor of the initial adjustment module (32), and the control component is used to control the first motor to adjust the moving distance of the reflector; The control component is connected to the second motor of the fine-tuning module (33), and the control component is used to control the second motor to adjust the deflection angle of the first reflector (34).

9. The ultraviolet laser with continuously adjustable pulse width according to claim 8, characterized in that, The ultraviolet light generating module (4) also includes a detection component; The detection component is connected to the control component; the detection component is located at the output port of the ultraviolet light generating module (4); The detection component is used to detect the pulse width and / or energy of ultraviolet light.

10. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The infrared laser (1) and the green light generating module (2) are further separated by a third waste light treatment device (7) and an isolator (8). The isolator (8) is disposed in the output optical path of the infrared laser (1); The third waste light treatment device (7) is installed on the waste light path reflected by the isolator (8).

11. The ultraviolet laser with continuously adjustable pulse width according to claim 1, characterized in that, The ultraviolet light generating module (4) is disposed on the input optical path of the green light generating module (2); the input optical path of the ultraviolet light generating module (4) is collinear with the input optical path of the green light generating module (2); The ultraviolet light generating module (4) is used to convert the light emitted by the green light generating module (2) into ultraviolet light and emit it.

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