Vortex laser generating device of off-axis pump

Abstract

The utility model discloses an off-axis pumped vortex laser generating device, which comprises a laser resonant cavity, a laser crystal and a cylindrical lens, the laser resonant cavity comprises an input mirror and an output mirror which are oppositely arranged, the laser crystal is arranged between the input mirror and the output mirror, and the cylindrical lens is arranged on one side, opposite to the laser crystal, of the output mirror; the input mirror is used for transmitting input pumping laser to obtain transmission pumping laser, the laser crystal is used for absorbing the transmission pumping laser and outputting target laser, the input mirror is further used for reflecting the target laser, and the laser resonant cavity is used for oscillating the target laser to enable the output mirror to output high-order mode laser. The cylindrical lens is used for converting the high-order mode laser into vortex laser. According to the invention, the structure is compact, by adjusting the relative position and the relative angle of the output mirror and the input mirror, the off-axis pumping laser and the high-order mode laser can coincide more, the oscillation of the high-order mode laser is improved, and the output efficiency of the vortex laser is further improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of vortex laser, and particularly relates to a vortex laser generating device with off-axis pumping. Background Art

[0002] Vortex lasers have significant advantages in the fields of optical micro-manipulation, laser communication, super-resolution imaging, etc., and are a highly competitive development direction in related fields in the future. At present, the applications of vortex light have been widely studied, and its advantages have also been proven. However, the current methods for generating vortex lasers are mainly extracavity generation methods, such as vortex laser phase plates [vortex optical fiber probes, preparation methods, scanning probes, and micro-nano manipulation systems, CN116360038A], metasurfaces [a holographic metasurface antenna for multimodal orbital angular momentum vortex beam shaping, CN117810703A], vortex gratings [a device and method for generating a nonlinear vector optical field, CN117908309A], etc. The vortex lasers obtained by extracavity methods face the problems of low purity and low laser conversion efficiency of vortex lasers. At present, some intracavity vortex laser generation methods have also been proposed, such as the ring light pumping method [a device for generating high-efficiency mid-infrared vortex lasers, CN219163901U], etc. However, these methods require lasers with special structures or pump lasers with special structures, resulting in an overly large overall volume and low efficiency of the lasers in generating vortex lasers.

[0003] To promote the development of related fields based on vortex lasers, it is very necessary to develop a vortex laser generation method with high efficiency and a compact structure. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the purpose of the present utility model is to provide a vortex laser generating device with off-axis pumping, which solves the problems of overly large volume and low efficiency of vortex laser generation in the prior art.

[0005] The present application provides a vortex laser generating device with off-axis pumping, including a laser resonator cavity, a laser crystal, and a cylindrical lens. The laser resonator cavity includes an input mirror and an output mirror arranged opposite to each other. The laser crystal is arranged between the input mirror and the output mirror. The cylindrical lens is arranged on the side of the output mirror opposite to the laser crystal. The input mirror is used for transmitting the input off-axis pumping laser to obtain transmitted pumping laser, and the input mirror is also used for reflecting the target laser. The laser crystal is used for absorbing the transmitted pumping laser and outputting the target laser. The laser resonator cavity is used for oscillating the target laser so that the output mirror outputs high-order mode output laser. The cylindrical lens is used for converting the high-order mode output laser into vortex laser. The position and angle of the output mirror relative to the input mirror are adjustable.

[0006] In some embodiments, the output mirror is parallel to the input mirror, and the output mirror and the input mirror are misaligned with each other.

[0007] In some embodiments, the bottom of the output mirror is higher than the bottom of the input mirror, where the bottom of the output mirror is the bottom end in the height direction of the output mirror, and the bottom of the input mirror is the bottom end in the height direction of the input mirror.

[0008] In some embodiments, an angle is set between the output mirror and the input mirror.

[0009] In some embodiments, the input mirror is parallel to the longitudinal direction, the top end of the output mirror is offset towards the input mirror, and the bottom end of the output mirror is offset away from the input mirror.

[0010] In some embodiments, the input mirror is parallel to the longitudinal direction, the top end of the output mirror is offset away from the input mirror, and the bottom end of the output mirror is offset towards the input mirror.

[0011] In some embodiments, the laser crystal is horizontally arranged transversely.

[0012] In some embodiments, an angle is set between the laser crystal and the input mirror.

[0013] In some embodiments, the output mirror is configured as a plano-concave lens with a concave first side and a flat second side, the concave side of the output mirror faces the input mirror, and the first side and the second side are two relatively arranged sides.

[0014] In some embodiments, the cylindrical lens is configured as a plano-convex lens with a convex third side and a flat fourth side, the convex side of the cylindrical lens faces the input mirror, and the third side and the fourth side are two relatively arranged sides.

[0015] In some embodiments, a light-transmitting film is coated on the input mirror, and the transmittance of the off-axis pump laser through the light-transmitting film is greater than 99%.

[0016] The present utility model includes but is not limited to the following beneficial effects: (1) In this application, the position and angle of the output mirror relative to the input mirror are adjustable, enabling the parameters of the laser resonator to be optimized as needed to adapt to different laser modes and application requirements. Further, the position and angle of the output mirror relative to the input mirror are adjustable, which can be adjusted to make the off-axis pump laser coincide more with the high-order mode laser, improving the oscillation and output efficiency of the high-order mode laser, and thus increasing the output efficiency of the vortex laser. (2) The input mirror and the output mirror are arranged in parallel, and the output mirror is translated upward relative to the input mirror by a certain distance. While maintaining the stability of the laser resonator, the coupling efficiency of the off-axis pump laser and the high-order mode laser can be optimized, improving the generation efficiency of the vortex laser. Further, the transmission path of the transmitted pump laser after passing through the input mirror in the laser resonator can be optimized, reducing losses during reflection and refraction, and improving the generation efficiency of the vortex laser. (3) The input mirror and the output mirror are arranged in parallel, simplifying the setting of the laser resonator and reducing the complexity of manufacturing and adjustment. (4) In this application, the angle between the output mirror and the input mirror is set and adjustable. By adjusting the angle of the output mirror, the mode selectivity of the laser resonator can be changed, and specific high-order mode lasers can be generated, improving the flexibility of generating the order of the vortex laser. Further, the angle adjustment can optimize the oscillation conditions of the target laser in the laser resonator, thereby increasing the generation efficiency of the vortex laser. (5) Horizontally setting the laser crystal transversely in the laser resonator can make the transmitted pump laser excite the crystal more uniformly, improving the utilization efficiency of the entire pump laser. (6) The angle setting between the laser crystal and the input mirror helps to optimize the propagation path of the light beam in the resonator, reducing unnecessary reflection and refraction losses, and increasing the generation efficiency of the vortex laser. Further, the coupling efficiency of the off-axis pump laser and the high-order mode laser can be optimized, increasing the generation efficiency of the vortex laser. (7) In this application, a light-transmitting film is coated on the input mirror, which can achieve a high transmittance of the pump laser, reducing the loss of the pump light. Since more pump light is transmitted into the laser crystal, the efficiency of the pumping process can be improved, thereby increasing the generation efficiency of the laser. Further, the transmission film can serve as a protective film for the input mirror, playing a certain protective role for the input mirror. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0018] Figure 1 It is a schematic diagram of the generation of vortex laser by the laser resonator in an embodiment of the present utility model;

[0019] Figure 2 It is a schematic diagram of a device for generating off-axis pumped vortex laser in an embodiment of the present utility model;

[0020] Figure 3 It is another schematic diagram of generating vortex laser of the laser resonator in the embodiment of the present utility model;

[0021] Figure 4 It is another schematic diagram of the off-axis pumped vortex laser generating device in the embodiment of the present utility model;

[0022] Figure 5 It is another schematic diagram of the off-axis pumped vortex laser generating device in the embodiment of the present utility model;

[0023] In the figure, 1 - input mirror, 2 - output mirror, 3 - fundamental mode laser, 4 - high-order mode laser, 5 - transmitted pump laser; 6 - laser crystal, 7 - high-order mode output laser, 8 - cylindrical lens, 9 - vortex laser. Specific embodiments

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0025] This application provides an off-axis pumped vortex laser generating device, which includes a laser resonator, a laser crystal 6 and a cylindrical lens 8. The laser resonator includes an input mirror 1 and an output mirror 2 arranged oppositely. The laser crystal 6 is arranged between the input mirror 1 and the output mirror 2, and the cylindrical lens 8 is arranged on the side of the output mirror 2 opposite to the laser crystal 6; the input mirror 1 is used for transmitting the input off-axis pump laser to obtain a transmitted pump laser 5, the laser crystal 6 is used for absorbing the transmitted pump laser 5 and outputting a target laser, the input mirror 1 is also used for reflecting the target laser, the laser resonator is used for oscillating the target laser so that the output mirror 2 outputs a high-order mode output laser 7, the cylindrical lens 8 is used for converting the high-order mode output laser 7 into a vortex laser 9, and the position and angle of the output mirror 2 relative to the input mirror 1 are adjustable. Off-axis pumping is a laser pumping technique that involves pumping the pump light at a certain distance offset from the axis of the laser resonator. This technique can be used to generate lasers with specific spatial modes, such as high-order mode lasers 4. Combining off-axis pumping with specific optical elements (such as cylindrical lens 8) can effectively generate vortex beams.

[0026] Further, in the embodiments of the present application, the position and angle of the output mirror 2 relative to the input mirror 1 are adjustable, so that the parameters of the laser resonator can be optimized as needed to adapt to different laser modes and application requirements; further, the position and angle of the output mirror 2 relative to the input mirror 1 are adjustable, and can be adjusted so that the off-axis pump laser coincides more with the high-order mode laser, improving the oscillation and output of the high-order mode laser, and thus improving the output efficiency of the vortex laser 9.

[0027] In some embodiments, the output mirror 2 in the laser resonator is arranged parallel to the input mirror 1. After the off-axis pump laser transmits through the input mirror 1, a transmitted pump laser 5 is formed. After the transmitted pump laser 5 enters the laser resonator, it pumps and oscillates the fundamental mode laser 3 and the high-order mode laser 4 generated by the laser crystal 6 in the laser resonator. In order to oscillate the high-order mode laser 4 while suppressing the oscillation of the fundamental mode laser, it is necessary to make the transmitted pump laser 5 coincide more with the high-order mode laser 4 and less with the fundamental mode laser. Therefore, as Figure 1 and Figure 2 shown, when the distribution of the fundamental mode laser 3 and the high-order mode laser 4 in the laser resonator is that the high-order mode laser 4, the fundamental mode laser 3, and the high-order mode laser 4 are arranged in sequence from top to bottom along the height direction of the input mirror 1, the position of the output mirror 2 relative to the input mirror 1 can be adjusted, that is, the output mirror 2 is longitudinally translated upward so that the bottom of the output mirror 2 is higher than the bottom of the input mirror 1, so that as Figure 1 and Figure 2 shown, after the transmitted pump laser 5 enters the laser resonator, it can pump the high-order mode laser 4 more, better realizing the oscillation of the high-order mode laser 4 and the output through the output mirror 2. The high-order mode output laser 7 output through the output mirror 2 is incident on the cylindrical lens 8 to obtain the vortex laser 9. Among them, the bottom of the output mirror 2 is the bottom end in the height direction of the output mirror 2, and the bottom of the input mirror 1 is the bottom end in the height direction of the input mirror 1. Specifically, the cylindrical lens 8 is an optical element with a cylindrical surface, and its main function is to perform phase modulation on light waves, especially to change the phase distribution of light waves. The high-order mode laser can be converted into a vortex beam (also called an optical vortex or a Laguerre-Gaussian beam). By introducing a phase gradient in the beam path, the cylindrical lens 8 can make the phase of the beam change radially, generating a spiral phase distribution.

[0028] It can be understood that by setting the input mirror 1 and the output mirror 2 in parallel and translating the output mirror 2 upward relative to the input mirror 1 by a certain distance, while maintaining the stability of the resonant cavity, the coupling efficiency of the off-axis pump laser and the high-order mode laser can be optimized, the generation efficiency of the vortex laser 9 can be improved, and further, the transmission path of the transmitted pump laser 5 after passing through the input mirror 1 in the resonant cavity can be optimized, reducing the losses during reflection and refraction, and improving the generation efficiency of the vortex laser 9; further, setting the input mirror 1 and the output mirror 2 in parallel simplifies the setting of the laser resonant cavity and reduces the complexity of manufacturing and adjustment.

[0029] In some embodiments, an angle is set between the output mirror 2 and the input mirror 1. As shown in FIGS. 3 and Figure 4 It can be seen that the input mirror 1 can be set parallel to the longitudinal direction, the top end of the output mirror 2 is offset towards the direction close to the input mirror 1, and the bottom end of the output mirror 2 is offset away from the input mirror 1. It can be understood that the angle between the output mirror 2 and the input mirror 1 is set and adjustable. By adjusting the angle of the output mirror 2, the mode selectivity of the laser resonant cavity can be improved, which is helpful for generating specific high-order mode lasers, improving the flexibility of the order generation of the vortex laser 9. Further, the angle adjustment can optimize the oscillation conditions of the transmitted pump laser 5 in the laser resonant cavity, thereby improving the generation efficiency of the vortex laser 9.

[0030] In still other embodiments, when the input mirror 1 is set parallel to the longitudinal direction, by adjusting the angle between the output mirror 2 and the input mirror 1, the top end of the output mirror 2 can also be offset away from the input mirror 1, and the bottom end of the output mirror 2 can be offset towards the input mirror 1.

[0031] In some embodiments, as shown in Figure 2 and Figure 4 the laser crystal 6 is horizontally arranged transversely in the laser resonant cavity, that is, the laser crystal 6 is horizontally arranged transversely between the input mirror 1 and the output mirror 2. Horizontally arranging the laser crystal 6 transversely in the laser resonant cavity can make the transmitted pump laser 5 excite the crystal more uniformly, improving the utilization efficiency of the entire laser medium.

[0032] In some embodiments, as shown in Figure 5 an angle is set between the laser crystal 6 and the input mirror 1. Setting an angle between the laser crystal 6 and the input mirror 1 helps to optimize the propagation path of the light beam in the resonant cavity, reduce unnecessary reflection and refraction losses, and improve the generation efficiency of the vortex laser 9. Further, the coupling efficiency of the off-axis pump laser and the high-order mode laser can be optimized, improving the generation efficiency of the vortex laser 9. It can be understood that the offset angle of the laser crystal 6 can be set based on the actual requirements of the specific high-order mode laser 4, and no specific limitation is provided here.

[0033] In some embodiments, the output mirror 2 is configured as a plano-concave lens with a concave first side and a flat second side. The concave side of the output mirror 2 faces the input mirror 1, and the first side and the second side are two opposite sides.

[0034] In some embodiments, the cylindrical lens 8 is configured as a plano-convex lens with a convex third side and a flat fourth side. The convex side of the cylindrical lens 8 faces the input mirror 1, and the third side and the fourth side are two opposite sides.

[0035] In some embodiments, a light-transmitting film is coated on the input mirror 1, and the light-transmitting film has a transmittance of greater than 99% for off-axis pump laser. Coating the light-transmitting film on the input mirror 1 can achieve a high transmittance of off-axis pump laser, reduce the loss of pump light. Since more pump light is transmitted into the laser crystal 6, the efficiency of the pumping process can be improved, thereby increasing the generation efficiency of the laser. Further, the transmissive film can serve as a protective film for the input mirror 1 and play a certain protective role for the input mirror 1.

[0036] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An off-axis pumped vortex laser generating device, characterized in that: The invention comprises a laser resonant cavity, a laser crystal (6) and a cylindrical lens (8), wherein the laser resonant cavity comprises an input mirror (1) and an output mirror (2) which are arranged opposite to each other, the laser crystal (6) being arranged between the input mirror (1) and the output mirror (2), and the cylindrical lens (8) being arranged on a side of the output mirror (2) opposite to the laser crystal (6); the input mirror (1) is used to transmit input off-axis pump laser light to obtain transmission pump laser light (5), the laser crystal (6) is used to absorb the transmission pump laser light (5) and output target laser light, the input mirror (1) is also used to reflect the target laser light, the laser resonant cavity is used to oscillate the target laser light so that the output mirror (2) outputs a high-order mode output laser light (7), the cylindrical lens (8) is used to convert the high-order mode output laser light (7) into a vortex laser light (9), and the position and angle of the output mirror (2) relative to the input mirror (1) are adjustable, wherein the off-axis pump laser light is generated based on the off-axis pump laser.

2. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The output mirror (2) is parallel to the input mirror (1), and the output mirror (2) and the input mirror (1) are offset from each other.

3. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The angle between the output mirror (2) and the input mirror (1) is set, and the angle between the output mirror (2) and the input mirror (1) is adjustable.

4. The off-axis pumped vortex laser generating device according to claim 3, characterized in that: The input mirror (1) is parallel to the longitudinal direction, the top end of the output mirror (2) is biased in a direction close to the input mirror (1), and the bottom end of the output mirror (2) is biased in a direction away from the input mirror (1).

5. The off-axis pumped vortex laser generating device according to claim 3, characterized in that: The input mirror (1) is parallel to the longitudinal direction, the top end of the output mirror (2) is biased in a direction away from the input mirror (1), and the bottom end of the output mirror (2) is biased in a direction close to the input mirror (1).

6. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The laser crystal (6) is arranged horizontally.

7. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The angle between the laser crystal (6) and the input mirror (1) is set.

8. The off-axis pumped vortex laser generating device according to any one of claims 1 to 5, characterized in that: The output mirror (2) is constructed as a plano-concave lens with a concave first side and a flat second side. The concave surface of the output mirror (2) faces the input mirror (1), and the first side and the second side are two oppositely disposed side surfaces.

9. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The cylindrical lens (8) is constructed as a plano-convex lens with a convex third side and a flat fourth side. The convex surface of the cylindrical lens (8) faces the input mirror (1), and the third side and the fourth side are two side surfaces arranged opposite to each other.

10. The off-axis pumped vortex laser generating device according to claim 1, characterized in that: The input mirror (1) is coated with a light-transmitting film, and the light-transmitting film has a transmittance greater than 99% for the off-axis pump laser.

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