A green laser

Abstract

This application provides a green laser, which sequentially includes a pump source, a collimating lens, a focusing lens, a first cavity mirror, a gain medium, a Q-switching element, and a second cavity mirror in a first direction; sequentially includes a third cavity mirror and a displacement motor in a second direction; and sequentially includes a first beam splitter, a frequency doubling crystal, and a fourth cavity mirror in a third direction. The third cavity mirror is located behind the second cavity mirror in the second direction, and the first beam splitter is located behind the first cavity mirror in the third direction. This application achieves adjustable cavity length by moving the third cavity mirror in the second direction through the position of the displacement motor. This allows the green laser to achieve a cavity length suitable for different power outputs by adjusting the cavity length, enabling the same green laser to output multiple power stably and continuously. Therefore, a green laser with precisely adjustable cavity length, compatible with multiple high and low power overlapping stable outputs, high integration, and compact structure is obtained.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically, to a green laser with adjustable cavity length and high stability. Background Technology

[0002] In recent years, with the booming demand from the new energy industry, higher requirements have been placed on front-end laser processing technology. The stability of a laser has a significant impact on its performance, especially when lasers are used in precision machining. The cavity length is particularly critical to laser stability. We know that the stability condition of a resonant cavity is: The curvatures R1 and R2 of a laser cavity mirror are generally specific in practical applications, and a controllable cavity length L can greatly improve the actual performance of the laser. The thermal lensing effect of high-power solid-state lasers is significant during operation. Traditional solid-state lasers can achieve relatively stable laser output under certain conditions, but when applications require overlapping high and low power output, a single laser is no longer sufficient, or when applications require lasers of different powers, compatibility becomes impossible. Green lasers, due to their shorter wavelength than infrared lasers and higher photon energy, are widely used in precision machining, crystal engraving, and other fields; their stability directly determines the yield rate of precision machining.

[0003] Therefore, it is necessary to invent a solid-state green laser that can produce green light output with adjustable cavity length, high stability, and compact structure. Summary of the Invention

[0004] The purpose of this application is to provide a green laser to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] This application provides a green laser that achieves adjustable cavity length, high stability, and compact green light output. The green laser sequentially includes, in a first direction, a pump source, a collimating lens, a focusing lens, a first cavity mirror, a gain medium, a Q-switching element, and a second cavity mirror; in a second direction, it sequentially includes a third cavity mirror and a displacement motor; and in a third direction, it sequentially includes a first beam splitter, a frequency doubling crystal, and a fourth cavity mirror. The third cavity mirror is located behind the second cavity mirror in the second direction, and the first beam splitter is located behind the first cavity mirror in the third direction.

[0007] The pump source is typically a semiconductor laser, which emits an infrared beam of approximately 808nm / 880nm. This infrared beam is output via an optical fiber jumper, then collimated by a collimating lens. When the beam passes through a focusing lens, it is focused, causing it to be concentrated within the gain medium after passing through the first cavity mirror. Thus, the pump source, optical fiber jumper, collimating lens, and focusing lens together constitute the pump coupling module of the green laser described in this application.

[0008] The Q-switching element can control the generation of the power pulses required for operation.

[0009] The first cavity mirror, the second cavity mirror, the third cavity mirror, and the fourth cavity mirror together constitute the resonant module of the green laser of this application, namely the resonant cavity.

[0010] The resonant principle of the green laser in this application is as follows: The pump light passing through the first cavity mirror undergoes stimulated emission within the gain medium, generating a 1000-1100nm infrared beam. Reflective films are deposited on corresponding sides of the first, second, third, and fourth cavity mirrors. The 1000-1100nm infrared beam, after passing through the second, third, and fourth cavity mirrors, is reflected back to the first cavity mirror, continuously forming a circuit. When the pump source continuously provides excitation, 1000-1100nm infrared photons continuously resonate within this circuit. The 1000-1100nm beam within the cavity undergoes a nonlinear effect when passing through the frequency-doubling crystal within the cavity, generating a 500-550nm beam. The 500-550nm green light is efficiently and stably output in a fourth direction through the 500-550nm high-reflectivity film side of the first beam splitter.

[0011] To match the varying power output of the green laser and eliminate the adverse effects of thermal lensing on the resonant cavity stability at different power levels, thereby achieving highly stable green light output, the third cavity mirror is fixed to a displacement motor. Moving the displacement motor moves the third cavity mirror in the second direction, thus allowing for adjustable cavity length. Simultaneously, the movement of the third cavity mirror in the second direction does not alter the overall optical path direction of the green laser when adjusting the cavity length, ensuring the stability of the green light output.

[0012] This application achieves adjustable cavity length by moving the third cavity mirror in the second direction through a displacement motor. This allows the green laser to be adjusted to the appropriate cavity length for different output powers, enabling the same green laser to output multiple powers stably and continuously. As a result, a green laser with precisely adjustable cavity length, compatible with multiple high and low power overlapping stable outputs, high integration, and compact structure is obtained. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A first structural schematic diagram of the green laser provided in this application;

[0015] Figure 2 A schematic diagram of the second structure of the green laser provided in this application;

[0016] Figure 3 This is a schematic diagram of the third structure of the green laser provided in this application;

[0017] Figure 4 A schematic diagram of the fourth structure of the green laser provided in this application;

[0018] Figure 5 The fifth structural schematic diagram of the green laser provided in this application.

[0019] Reference numerals: 1. Pump source; 2. Collimating lens; 3. Focusing lens; 4. First cavity mirror; 5. Gain medium; 6. First pinhole aperture; 7. Q-switching element; 8. Second pinhole aperture; 9. Second cavity mirror; 10. Third cavity mirror; 11. First idler light collector; 12. Displacement motor; 13. Third pinhole aperture; 14. First beam splitter; 15. Temperature control module; 16. Frequency doubling crystal; 17. Fourth cavity mirror; 18. Second idler light collector; 19. Fourth pinhole aperture; 20. Second beam splitter; 21. Third beam splitter; 22. Third idler light collector; 23. Fourth idler light collector. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present application and are not intended to limit the scope of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.

[0021] Please see Figure 1 , Figure 1The first structural schematic diagram of the green laser provided in this application shows that the green laser includes, in the first direction, a pump source 1, a collimating lens 2, a focusing lens 3, a first cavity mirror 4, a gain medium 5, a Q-switching element 7, and a second cavity mirror 9; in the second direction, it includes a third cavity mirror 10 and a displacement motor 12; and in the third direction, it includes a first beam splitter 14, a frequency doubling crystal 16, and a fourth cavity mirror 17. The third cavity mirror 10 is located behind the second cavity mirror 9 in the second direction, and the first beam splitter 14 is located behind the first cavity mirror 4 in the third direction.

[0022] The pump source 1 is generally a semiconductor laser, which emits an infrared beam of approximately 808nm / 880nm. This infrared beam is output via an optical fiber jumper (not shown in the figure), collimated by a collimating lens 2, and then focused by a focusing lens 3. After passing through the first cavity mirror 4, the beam is focused within the gain medium 5. Thus, the pump source 1, the optical fiber jumper, the collimating lens 2, and the focusing lens 3 together constitute the pump coupling module of the green laser of this application.

[0023] The first cavity mirror 4, the second cavity mirror 9, the third cavity mirror 10 and the fourth cavity mirror 17 together constitute the resonant module of the green laser of this application, namely the resonant cavity.

[0024] The resonant principle of the green laser in this application is as follows: The pump light passing through the first cavity mirror 4 undergoes stimulated emission within the gain medium 5, generating a 1000-1100nm infrared beam. This beam is reflected by the second cavity mirror 9 to the third cavity mirror 10, then reflected back through the third cavity mirror 10, and then reflected again by the second cavity mirror 9 and the first cavity mirror 4 before being reflected back through the fourth cavity mirror 17. The beam reflected back through the fourth cavity mirror 17 is then reflected by the first cavity mirror 4, thus completing one loop. The 1000-1100nm beam within the cavity undergoes a nonlinear effect when passing through the frequency doubling crystal 16, generating a 500-550nm beam. As the pump source 1 continuously provides excitation, 1000-1100nm infrared photons continuously resonate within this loop.

[0025] To ensure efficient and stable operation of the resonant cavity, the side of the first cavity mirror 4 closest to the gain medium 5 or the first beam splitter 14 is coated with a 1000-1100nm high-reflectivity film. The side of the second cavity mirror 9 closest to the Q-switching element 7 or the third cavity mirror 10 is coated with a 1000-1100nm high-reflectivity film. The side of the third cavity mirror 10 closest to the second cavity mirror 9 is coated with a 1000-1100nm high-reflectivity film. The side of the fourth cavity mirror 17 closest to the first beam splitter 14 is coated with both 1000-1100nm and 500-550nm high-reflectivity films. The side of the first beam splitter 14 closest to the fourth cavity mirror 17 is also coated with a 500-550nm high-reflectivity film. This allows for efficient and stable output of 500-550nm green light in the fourth direction through the 500-550nm high-reflectivity film on the side of the first beam splitter 14.

[0026] The Q-switching element 7 can control the generation of the required power pulse. In a specific embodiment, an acousto-optic Q-switching element can be used.

[0027] To match the varying power levels generated by the green laser and achieve highly stable green light output, the third cavity mirror 10 is fixed to the displacement motor 12. Moving the displacement motor 12 moves the third cavity mirror 10 in the second direction, thus allowing for adjustable cavity length. Simultaneously, the movement of the third cavity mirror 10 in the second direction does not alter the overall optical path direction of the green laser when adjusting the cavity length, ensuring stable green light output. The displacement motor 12 is a precision displacement motor, and its movement can be controlled via software.

[0028] In a preferred embodiment, the first cavity mirror 4 is positioned at a 60° angle to both the first and third-direction optical paths, while the second cavity mirror 9 is positioned at a 45° angle to both the first and second direction optical paths. The devices in the second and third directions are all located on the same side of the first direction. This structural configuration allows the green laser of this application to be a highly integrated and compact laser. Furthermore, adjusting the cavity length does not change the overall optical path direction of the green laser, ensuring the stability of the green light output.

[0029] Furthermore, in order to reduce beam energy loss and improve pump light transmittance, the collimating lens 2, focusing lens 3, first cavity mirror 4, gain medium 5, and the front and rear end faces of the Q-switching element 7 are all coated with an 808 / 880nm antireflection film.

[0030] Furthermore, in order to make full and effective use of the beam, the front and rear ends of the gain medium 5, the Q-switching element 7 and the first beam splitter 14 are all coated with a 1000-1100nm anti-reflection film, and both sides of the frequency doubling crystal 16 are coated with a 1000-1100nm and a 500-550nm anti-reflection film.

[0031] Furthermore, in order to improve the overall stability of the device, a heat sink structure is provided on the gain medium 5, which promptly dissipates excess heat from the gain medium 5.

[0032] Further, please refer to Figure 2 , Figure 2 The second structural diagram of the green laser provided in this application shows that a temperature control module 15 is also sleeved on the outside of the frequency doubling crystal 16. The temperature control module 15 provides a stable temperature environment for the frequency doubling crystal 16, thereby improving the overall stability of the device.

[0033] Furthermore, to reduce the interference of idler light on resonance, both sides of the first cavity mirror 4 are coated with a 500-550nm anti-reflection film, and both sides of the second cavity mirror 9 and the third cavity mirror 10 are coated with an 808 / 880nm anti-reflection film.

[0034] Further, please refer to Figure 3 , Figure 3 This is a schematic diagram of the third structure of the green laser provided in this application. To achieve more efficient and stable output of 500-550nm green light, and to obtain purer 500-550nm green light, this green laser... Figure 2 Based on the green laser shown, it may further include a second beam splitter 20. The second beam splitter 20 is located behind the first beam splitter 14 in the fourth direction, positioned at a 45° angle to the optical path in the fourth direction, and is located on the side closer to the third cavity mirror 10. The second beam splitter 20 has a 1000-1100nm anti-reflection coating on both sides, and a 500-550nm high-reflection coating on the side closer to the first beam splitter 14. The 500-550nm green light, reflected by the first beam splitter 14, is reflected by the 500-550nm high-reflection coating of the second beam splitter 20, allowing for efficient and stable output of the green light from the fifth direction. This structural configuration makes the green laser of this application a highly integrated and compact laser.

[0035] The green laser may further include a third beam splitter 21, located behind the second beam splitter 20 in the fifth direction and away from the first direction, at a 45° angle to the optical path in the fifth direction. The third beam splitter has a 1000-1100nm anti-reflection coating on both sides and a 500-550nm high-reflection coating on the side closest to the second beam splitter 20. The 500-550nm green light is reflected by the first beam splitter 14 to the second beam splitter 20, and then passes through the 500-550nm high-reflection coating of the third beam splitter 21, ultimately resulting in efficient and stable green light output from the sixth direction. This structural configuration allows the green laser of this application to be a highly integrated and compact laser.

[0036] It should be noted that, in order to achieve more efficient and stable output of 500-550nm green light and obtain purer 500-550nm green light, the green laser of this application is equipped with a second beam splitter 20. To obtain particularly high-quality 500-550nm green light, the green laser of this application is equipped with both a second beam splitter 20 and a third beam splitter 21.

[0037] Further, please refer to Figure 4 , Figure 4 This is a schematic diagram of the fourth structure of the green laser provided in this application. This green laser, in... Figure 3 Based on the green laser with a second beam splitter 20 shown, it may further include: a first pinhole stop 6, a second pinhole stop 8, a third pinhole stop 13, and a fourth pinhole stop 19. The first pinhole stop 6 is located between the gain medium 5 and the Q-switching element 7, and can limit mode and block off-axis stray light, improving the overall system optical path stability. The second pinhole stop 8 is located between the Q-switching element 7 and the second cavity mirror 9, and can filter out the diffracted light after passing through the Q-switching element 7. The third pinhole stop 13 is located between the first cavity mirror 4 and the first beam splitter 14, and similarly, can limit mode and block off-axis stray light, improving the overall system optical path stability. The fourth pinhole stop 19 is located between the first beam splitter 14 and the second beam splitter 20, and can limit the output green light, improving the output green light quality.

[0038] Further, please refer to Figure 5 , Figure 5 This is a schematic diagram of the fifth structure of the green laser provided in this application. To reduce the interference of idler light on resonant operation and obtain stable green light output, this green laser... Figure 4Based on the green laser shown, it further includes: a first idler light collector 11, a second idler light collector 18, a third idler light collector 22, and a fourth idler light collector 23; the first idler light collector 11 is located on the side of the second cavity mirror 9 away from the Q-switching element 7 in a first direction, and is mainly used to collect 808 / 880nm and 500-550nm idler light; the second idler light collector 18 is located on the side of the first cavity mirror 4 away from the first beam splitter 14 in a third direction, and mainly collects 500-550nm idler light; the third idler light collector 22 is located on the side of the first cavity mirror 4 away from the first beam splitter 14 in a fourth direction, and mainly collects 1000-1100nm idler light; the fourth idler light collector 23 is located on the side of the third beam splitter 21 away from the second beam splitter 20 in a fifth direction, and mainly collects 1000-1100nm idler light. The first idler frequency optical collector 11, the second idler frequency optical collector 18, the third idler frequency optical collector 22, and the fourth idler frequency optical collector 23 are all used for the absorption and heat dissipation of residual fundamental frequency signal light. The residual fundamental frequency signal light and the incompletely reflected frequency harmonic light that pass through these devices will be annihilated in these idler frequency optical collectors, thereby improving the system stability and the purity of the output green light.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0040] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made to this application, as well as combinations of the various embodiments in this application, without departing from the principles of this application. These improvements, modifications, and combinations also fall within the protection scope of the claims of this application.

Claims

1. A green laser, characterized in that... In the first direction, it includes, in sequence, a pump source (1), a collimating lens (2), a focusing lens (3), a first cavity mirror (4), a gain medium (5), a Q-switching element (7), and a second cavity mirror (9); The second direction includes a third cavity mirror (10) and a displacement motor (12) in sequence, wherein the third cavity mirror (10) is located behind the second cavity mirror (9) in the second direction; The third direction includes a first beam splitter (14), a frequency doubling crystal (16), and a fourth cavity mirror (17) in sequence. The first beam splitter (14) is located behind the first cavity mirror (4) in the third direction. The pump source (1) is a semiconductor laser that emits an infrared beam of 808nm / 880nm. After the infrared beam is output through the fiber optic jumper, it is collimated by the collimating lens (2). When the beam passes through the focusing lens (3), it is focused by the focusing lens (3) and then focused in the gain medium (5) after passing through the first cavity mirror (4). The pump light passing through the first cavity mirror (4) undergoes stimulated emission in the gain medium (5) to generate an infrared beam of 1000-1100nm. This beam is reflected by the second cavity mirror (9) to the third cavity mirror (10) and then reflected back by the third cavity mirror (10). After being reflected by the second cavity mirror (9) and the first cavity mirror (4), it is reflected back at the fourth cavity mirror (17). The beam reflected back at the fourth cavity mirror (17) is then reflected by the first cavity mirror (4) to complete a loop. The 1000-1100nm beam inside the cavity will undergo a nonlinear effect when passing through the frequency doubling crystal (16), generating a 500-550nm beam; The first cavity mirror (4) has a 1000-1100nm high reflectivity film on one side near the gain medium (5) or the first beam splitter (14). The second cavity mirror (9) has a 1000-1100nm high reflectivity film on one side near the Q-switching element (7) or the third cavity mirror (10). The third cavity mirror (10) has a 1000-1100nm high reflectivity film on one side near the second cavity mirror (9). The fourth cavity mirror (17) has a 1000-1100nm and 500-550nm high reflectivity film on one side near the first beam splitter (14). The first beam splitter (14) also has a 500-550nm high reflectivity film on one side near the fourth cavity mirror (17). The third cavity mirror (10) is fixed on the displacement motor (12), and the third cavity mirror (10) is moved in the second direction by moving the position of the displacement motor (12).

2. The green laser according to claim 1, characterized in that... The first cavity mirror (4) is placed at 60° to the optical paths in the first direction and the third direction, and the second cavity mirror (9) is placed at 45° to the optical paths in the first direction and the second direction. The devices in the second direction and the third direction are all located on the same side of the first direction.

3. The green laser according to claim 1, characterized in that... The collimating lens (2), focusing lens (3), first cavity mirror (4), gain medium (5) and Q-switching element (7) are all coated with 808 / 880nm anti-reflection film on their front and rear ends.

4. The green laser according to claim 1, characterized in that... The front and rear ends of the gain medium (5), Q-switching element (7) and first beam splitter (14) are all coated with 1000-1100nm anti-reflection film, and both sides of the frequency doubling crystal (16) are coated with 1000-1100nm and 500-550nm anti-reflection film.

5. The green laser according to claim 1, characterized in that... A temperature control module (15) is fitted around the frequency doubling crystal (16).

6. The green laser according to claim 1, characterized in that... The first cavity mirror (4) is coated with a 500-550nm anti-reflection film on both sides, and the second cavity mirror (9) and the third cavity mirror (10) are coated with an 808 / 880nm anti-reflection film on both sides.

7. The green laser according to claim 5, characterized in that... It may also include a second beam splitter (20), which is located behind the first beam splitter (14) in the fourth direction and is placed at 45° to the optical path in the fourth direction, and the second beam splitter (20) is located on the side close to the third cavity mirror (10). The second beam splitter (20) is coated with a 1000-1100nm anti-reflection film on both sides, and a 500-550nm high-reflection film is coated on one side near the first beam splitter (14). The 500-550nm green light is reflected by the first beam splitter (14) to the 500-550nm high-reflection film of the second beam splitter (20) and output from the fifth direction.

8. The green laser as described in claim 7, characterized in that, It also includes a third beam splitter (21), which is located behind the second beam splitter (20) in the fifth direction and away from the first direction. It is placed at 45° with the light path in the fifth direction. The third beam splitter is coated with a 1000-1100nm anti-reflection film on both sides and a 500-550nm high reflectivity film on the side close to the second beam splitter (20). The 500-550nm green light is reflected by the first beam splitter (14) to the second beam splitter (20) and then output from the sixth direction through the 500-550nm high reflectivity film of the third beam splitter (21).

9. The green laser as described in claim 7, characterized in that, Also includes: First pinhole aperture 6, second pinhole aperture 8, third pinhole aperture (13), fourth pinhole aperture (19); The first pinhole aperture 6 is located between the gain medium (5) and the Q-switching element (7), the second pinhole aperture 8 is located between the Q-switching element (7) and the second cavity mirror (9), the third pinhole aperture (13) is located between the first cavity mirror (4) and the first beam splitter (14), and the fourth pinhole aperture (19) is located between the first beam splitter (14) and the second beam splitter (20).

10. The green laser as described in claim 9, characterized in that, Also includes: First idler optical collector (11), second idler optical collector (18), third idler optical collector (22), fourth idler optical collector (23); The first idler light collector (11) is located on the side of the second cavity mirror (9) away from the Q-switching element (7) in a first direction, the second idler light collector (18) is located on the side of the first cavity mirror (4) away from the first beam splitter (14) in a third direction, the third idler light collector (22) is located on the side of the first cavity mirror (4) away from the first beam splitter (14) in a fourth direction, and the fourth idler light collector (23) is located on the side of the third beam splitter (21) away from the second beam splitter (20) in a fifth direction.

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