Double-layer folding polarization coupling output laser

Abstract

The utility model discloses a double-layer folding polarization coupling output laser which comprises a first porro prism, a door closing wave plate, a Q-switching assembly, a first PBS prism, a second PBS prism, an optical wedge pair, a gain assembly, a 1 / 4 lambda wave plate, a first cube-corner prism, a second cube-corner prism and a second porro prism. The first porro prism is set as a resonant cavity starting point, and light is reflected by the first PBS prism and the second PBS prism after passing through the door closing wave plate and the Q-switching assembly, so that first horizontal folding is completed. The light is reflected by the second PBS prism, passes through the optical wedge pair, the gain assembly and the 1 / 4 lambda wave plate, and then enters the first cube-corner prism to complete first vertical folding. And the light is emitted from the first cube-corner prism and then enters the second cube-corner prism, so that second horizontal folding is completed. And finally, the light is transmitted to the second porro prism and returns along the same path, the vertical component linearly polarized light is reflected to maintain oscillation when passing through the second PBS prism, and the horizontal component linearly polarized light is transmitted to be output by the laser. The laser is compact in structure and has stability and light beam quality.

Description

Technical Field

[0001] The utility model relates to the technical field of lasers, in particular to a double-layer folded polarization coupled output laser. Background Art

[0002] With the development of solid-state laser technology, high-energy solid-state lasers have been rapidly developed and applied in laser ranging, laser irradiation, laser radar, etc. Especially in the military and aerospace fields, there are extremely high requirements for the volume and weight, reliability and stability, and environmental adaptability of lasers. Therefore, compact and stable lasers are of great significance to practical needs.

[0003] To obtain a compact and stable laser, the design of the resonant cavity is the key. In order to obtain a laser with a small volume and high beam quality output, the current solutions include a large cavity length laser based on a folded structure, such as a Z-shaped folded cavity and a U-shaped folded cavity; or an end-pumped laser that outputs the fundamental transverse mode. The conventional folding method has limited volume compression, and the end-pumping method is not suitable for high energy output. Gaussian mirrors and unstable cavities are effective ways to achieve small volumes and high beam quality, but there are also problems such as low efficiency. Utility Model Content

[0004] The utility model aims to provide a double-layer folded polarization coupled output laser, which can reduce the length and volume of the laser while ensuring the quality and stability of the laser beam.

[0005] In order to solve the above technical problems, the utility model provides a technical solution: a double-layer folded polarization coupled output laser, comprising a first porro prism, a gate wave plate, a Q-switching component, a first PBS prism, a second PBS prism, an optical wedge pair, a gain component, a 1 / 4λ wave plate, a first corner cube prism, a second corner cube prism, and a second porro prism arranged in sequence along the optical path;

[0006] The first porro prism is set as the starting point of the resonant cavity. After the light passes through the gate wave plate and the Q-switching component, it is reflected by the first PBS prism and the second PBS prism in sequence to complete the first horizontal folding of the light path. After the light is reflected by the second PBS prism, it passes through the wedge pair, the gain component, and the 1 / 4λ wave plate, and then enters the first corner cube prism, where it is reflected multiple times. The light path is folded 180 degrees in the vertical plane to complete the vertical folding of the light path. After the light exits the first corner cube prism, it enters the second corner cube prism, where it is reflected multiple times. The light path is folded 180 degrees in the horizontal plane to complete the second horizontal folding of the light path. Then the light is transmitted to the second porro prism and reflected and then returns along the original path in sequence. When passing through the second PBS prism, the reflected vertical component linear polarization light maintains oscillation, and the transmitted horizontal component linear polarization light is used as the laser output. A polarization-coupled output resonant cavity is formed between the first porro prism and the second porro prism along the light path.

[0007] According to the above scheme, the Q-switching component includes a Q-switching crystal and a voltage-applying device for establishing a voltage across the two ends of the Q-switching crystal.

[0008] According to the above scheme, the gain component includes a gain medium and a pump source.

[0009] According to the above scheme, the gain medium is a slab-shaped doped crystal.

[0010] According to the above scheme, the gain medium is a rod-shaped doped crystal.

[0011] According to the above scheme, the pump source is a laser diode array.

[0012] According to the above scheme, the gate wave plate and the 1 / 4λ wave plate are zero-order wave plates corresponding to the wavelength of the laser.

[0013] According to the above scheme, the ridge lines of the first porro prism and the second porro prism are placed crosswise.

[0014] The beneficial effects of the utility model are: the optical path is folded 180 degrees multiple times by using the first PBS prism, the second PBS prism, the first corner cube prism, and the second corner cube prism, so that the laser has a larger resonant cavity length in a smaller length space, and the laser beam quality and pulse width are improved. The cavity mirror adopts the first porro prism and the second porro prism which are cross-arranged, and its self-alignment characteristics make the laser have high stability and environmental adaptability. The adopted porro prism and corner cube prism can further improve the laser beam quality, reduce the difficulty of laser debugging, and facilitate engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the optical structure and optical path of a double-layer folded polarization-coupled output laser according to an embodiment of the utility model.

[0016] In the figure: 1-first porro prism, 2-gate wave plate, 3-Q-switching component, 4-first PBS prism, 5-second PBS prism, 6-optical wedge pair, 7-gain component, 8-1 / 4λ wave plate, 9-first corner cube prism, 10-second corner cube prism, 11-second porro prism. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0018] See also Figure 1 A double-layer folded polarization coupled output laser comprises a first porro prism 1, a gate wave plate 2, a Q-switching component 3, a first PBS prism 4, a second PBS prism 5, a wedge pair 6 (the resonant cavity alignment is finely adjusted by rotating the wedge pair in the cavity. In this embodiment, in order to balance the adjustment capability and stability, the wedge angle of the wedge is about 10 minutes), a gain component 7, a 1 / 4λ wave plate 8, a first corner cube prism 9, a second corner cube prism 10, and a second porro prism 11.

[0019] The first porro prism 1 is set as the starting point of the resonant cavity. After the light passes through the gate wave plate 2 and the Q-switching component 3, it is reflected by the first PBS prism 4 and the second PBS prism 5 in sequence, completing the first horizontal folding of the light path (and then forming the upper U-shaped folded light path). After the light is reflected by the second PBS prism 5, it passes through the optical wedge pair 6, the gain component 7, and the 1 / 4λ wave plate 8, and enters the first corner cube prism 9. It is reflected multiple times in the first corner cube prism 9, and the light path is folded 180 degrees on the vertical plane to complete the vertical folding of the light path. The light exits the first corner cube prism After the light is incident on the second corner cube prism 10, it is reflected multiple times in the second corner cube prism 10, and the light path is bent 180 degrees in the horizontal plane, completing the second horizontal folding of the light path (thus forming a lower U-shaped folded light path), and then the light is transmitted to the second porro prism 11 and returns to the original path after reflection. When passing through the second PBS prism 5, the reflected vertical component linear polarized light maintains oscillation, and the transmitted horizontal component linear polarized light is used as laser output; a polarization-coupled output resonant cavity is formed along the light path between the first porro prism 1 and the second porro prism 11.

[0020] Furthermore, the Q-switching component 3 includes a Q-switching crystal and a voltage-applying device for establishing a voltage across the Q-switching crystal.

[0021] Furthermore, the gain component 7 includes a gain medium and a pump source, and the pump source provides pump light by a lateral pumping method.

[0022] Furthermore, the gain medium is a slab-shaped doped crystal, and in other embodiments, it may also be a rod-shaped doped crystal.

[0023] Furthermore, the pump source is a (narrow linewidth high power) laser diode array.

[0024] Furthermore, the gate-closing wave plate 2 and the 1 / 4λ wave plate 8 are zero-order wave plates corresponding to the wavelength of the laser.

[0025] The working principle of the laser in this embodiment is as follows:

[0026] The first porro prism 1 and the second porro prism 11 are placed orthogonally as cavity mirrors, and form a polarization-coupled output resonant cavity with the PBS prism and the 1 / 4λ wave plate 8. The 1 / 4λ wave plate 8 is rotated to adjust and change the output rate of the resonant cavity; the first PBS prism 4, the second PBS prism 5, the Q-switched crystal, the gate wave plate 2, and the first porro prism 1 form a pressurized Q-switched optical path.

[0027] The laser gain medium is a doped crystal rod or slab, and the pump light is provided by high-power laser diodes arranged around it. The gate wave plate 2 and the 1 / 4λ wave plate 8 are zero-order wave plates corresponding to the laser output wavelength to reduce the influence of a wide temperature range. The gate wave plate 2 selects the corresponding phase delay amount according to the installation angle of the ridge line of the first porro prism 1. The wedge pair 6 is composed of two identical wedges.

[0028] The pumped laser gain medium generates stimulated radiation in the resonant cavity formed by the first porro prism 1 and the second porro prism 11. The light in the cavity reflects the vertical component linear polarization light through the second PBS prism 5 and transmits the horizontal component linear polarization light. The horizontal component linear polarization light is used as the laser output, and the vertical component linear polarization light continues to be reflected by the first PBS prism 4 and then reaches the first porro prism 1 and feedback oscillation.

[0029] The vertical linear polarized light oscillating in the resonant cavity will be depolarized and become elliptically polarized light after passing through the 1 / 4λ wave plate 8, the first corner cube prism 9, the second corner cube prism 10, and the second porro prism 10. The fast and slow axis directions of the rotating 1 / 4λ wave plate 8 are adjusted to change the ratio of the horizontal component to the vertical component of the elliptically polarized light, thereby adjusting the output rate passing through the second PBS prism 5.

[0030] The first corner cube prism 9 realizes the folding of the upper and lower optical paths, and the second corner cube prism 10 realizes the left and right folding of the lower optical path. The laser will be depolarized when passing through the corner cube prism, and generally a specific wave plate is required to compensate. The first corner cube prism 9 and the second corner cube prism 10 are placed adjacent to each other orthogonally in the optical path, and the depolarization of the vertical component and the horizontal component of the laser are orthogonally offset, and no depolarization is generated as a whole. The 1 / 4λ wave plate 8 is rotated and combined with the depolarization effect of the second porro prism 11 to achieve the adjustment of the coupling output rate from 0 to 100%.

[0031] From the start of pumping to the accumulation of the reversed particle number density in the laser gain medium reaching the maximum value, no voltage is applied to the Q-switched crystal. The vertical component linear polarized light reflected by the second PBS prism 5 and the first PBS prism 4 passes through the Q-switched crystal, the gate wave plate 2, and the first porro prism 1, and returns along the original optical path after reflection. The gate wave plate 2 is rotated, so that the vertical linear polarized light originally passing through the first PBS prism 4 becomes horizontal linear polarized light after reflection and transmits out of the resonant cavity. At this time, the loss in the cavity is extremely large and feedback oscillation cannot be formed. When the reversed particle number density in the gain medium reaches the maximum value, applying appropriate high voltage to the Q-switched crystal is equivalent to inserting a specific wave plate. The polarization state of the vertical linear polarized light in the cavity does not change after reflection. At this time, the loss in the cavity drops sharply, feedback is generated in the laser cavity and oscillates rapidly, and Q-switched giant pulse laser is generated.

[0032] The double-layer folded polarization-coupled output laser of this embodiment has a compact structure, high output laser beam quality, large pulse width, can work stably and reliably under high and low temperature, vibration and shock conditions, has small output energy differences at different operating frequencies, and is easy to debug.

[0033] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A double-layer folded polarization-coupled output laser, Features: It includes a first porro prism, a shutter wave plate, a Q-switching component, a first PBS prism, a second PBS prism, an optical wedge pair, a gain component, a 1 / 4λ wave plate, a first corner cube prism, a second corner cube prism, and a second porro prism, which are sequentially arranged along the optical path; The first porro prism is set as the starting point of the resonant cavity. After the light passes through the gate wave plate and the Q-switching component, it is reflected by the first PBS prism and the second PBS prism in sequence to complete the first horizontal folding of the light path. After the light is reflected by the second PBS prism, it passes through the wedge pair, the gain component, and the 1 / 4λ wave plate, and then enters the first corner cube prism, where it is reflected multiple times. The light path is folded 180 degrees in the vertical plane to complete the vertical folding of the light path. After the light exits the first corner cube prism, it enters the second corner cube prism, where it is reflected multiple times. The light path is folded 180 degrees in the horizontal plane to complete the second horizontal folding of the light path. Then the light is transmitted to the second porro prism and reflected and then returns along the original path in sequence. When passing through the second PBS prism, the reflected vertical component linear polarization light maintains oscillation, and the transmitted horizontal component linear polarization light is used as the laser output. A polarization-coupled output resonant cavity is formed between the first porro prism and the second porro prism along the light path.

2. The double-layer folded polarization-coupled output laser according to claim 1, Features: The Q-switching component includes a Q-switching crystal and a voltage-applying device for establishing a voltage across the Q-switching crystal.

3. The double-layer folded polarization-coupled output laser according to claim 1, Features: The gain component includes a gain medium and a pump source.

4. The double-layer folded polarization-coupled output laser according to claim 3, Features: The gain medium is a slab-doped crystal.

5. The double-layer folded polarization-coupled output laser according to claim 3, Features: The gain medium is a rod-shaped doped crystal.

6. The double-layer folded polarization-coupled output laser according to claim 3, Features: The pump source is a laser diode array.

7. The double-layer folded polarization-coupled output laser according to claim 1, Features: The gate wave plate and the 1 / 4λ wave plate are zero-order wave plates corresponding to the wavelength of the laser.

8. The double-layer folded polarization-coupled output laser according to claim 1, Features: The ridge lines of the first porro prism and the second porro prism are placed crosswise.

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