A Q-switching mode switchable laser

Abstract

The application relates to a Q-switchable laser, which comprises a laser assembly, an electro-optic Q-switching assembly, an acousto-optic Q-switching assembly and a polarizer, wherein the polarizer is arranged on an output light path of the laser assembly, the electro-optic Q-switching assembly is arranged on one side of the polarizer, the acousto-optic Q-switching assembly is arranged on the other side of the polarizer, the laser assembly is provided with a main cavity mirror, the electro-optic Q-switching assembly comprises an electro-optic Q-switching crystal and an electro-optic cavity mirror, the electro-optic Q-switching crystal is arranged between the electro-optic cavity mirror and the polarizer, the electro-optic Q-switching crystal is connected with a first power-on module, the acousto-optic Q-switching assembly comprises an acousto-optic Q-switching crystal and an acousto-optic cavity mirror, the acousto-optic Q-switching crystal is arranged between the polarizer and the acousto-optic cavity mirror, and the acousto-optic Q-switching crystal is connected with a second power-on module. The application can operate in the electro-optic Q-switching mode and the acousto-optic Q-switching mode, and has the advantage that one laser has two working modes.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a laser with switchable Q-switching mode. Background Technology

[0002] Q-switching is a technique for obtaining high peak power, narrow pulse width laser pulses. The application of Q-switching can achieve pulsed laser output with peak power exceeding megawatts and pulse widths on the order of nanoseconds, greatly expanding the application scenarios of laser technology.

[0003] Based on the energy storage method, Q-switching technology can be divided into two types: working medium energy storage and resonant cavity energy storage. Among the working medium energy storage technologies, the widely used Q-switching technologies include electro-optic Q-switching and acousto-optic Q-switching.

[0004] Electro-optic Q-switching utilizes the Pockels effect (linear photoelectric effect) of crystals to achieve a sudden change in Q-value. Electro-optic Q-switching offers advantages such as short switching time, high efficiency, precise control of the Q-switching timing, stable system operation, narrow output pulse width (tens of nanoseconds), and high pulse energy. However, its repetition frequency is typically low (in the hundreds of hertz range). Acousto-optic Q-switching utilizes the acousto-optic diffraction effect of acousto-optic devices to control resonant cavity loss and achieve a sudden change in Q-value. Acousto-optic Q-switching devices offer advantages such as stable performance, high repetition frequency (in the megahertz range), and low modulation voltage, making them suitable for low-to-medium power, high-repetition-frequency lasers. However, their pulse width is relatively wide, and their pulse energy is relatively low.

[0005] Electro-optic Q-switching and acousto-optic Q-switching are typically used in different applications. However, for scenarios requiring both high-pulse-energy lasers and high-repetition-rate lasers, two lasers are usually needed. On the one hand, the switching time between the two lasers is relatively long, increasing time costs; on the other hand, equipping two lasers also increases economic costs. Summary of the Invention

[0006] The purpose of this invention is to provide a laser with switchable Q-switching mode, which can operate in both electro-optic Q-switching and acousto-optic Q-switching modes, thus having the advantage of having two operating modes in one laser.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A laser with switchable Q-switching mode includes a laser assembly, an electro-optic Q-switching assembly, an acousto-optic Q-switching assembly, and a polarizer. The polarizer is disposed in the output optical path of the laser assembly. The electro-optic Q-switching assembly is disposed on one side of the polarizer, and the acousto-optic Q-switching assembly is disposed on the other side of the polarizer. The laser assembly has a main cavity mirror. The electro-optic Q-switching assembly includes an electro-optic Q-switching crystal and an electro-optic cavity mirror, with the electro-optic Q-switching crystal disposed between the electro-optic cavity mirror and the polarizer. The electro-optic Q-switching crystal is connected to a first power-on module. The acousto-optic Q-switching assembly includes an acousto-optic Q-switching crystal and an acousto-optic cavity mirror, with the acousto-optic Q-switching crystal disposed between the polarizer and the acousto-optic cavity mirror. The acousto-optic Q-switching crystal is connected to a second power-on module.

[0009] The electro-optic Q-switching component includes a first λ / 4 waveplate, which is disposed between the electro-optic Q-switching crystal and the polarizer.

[0010] The reflective surface of the electro-optic cavity mirror is coated with a high reflectivity film with a laser reflectivity greater than 99%, and the light-transmitting surfaces of the first λ / 4 waveplate and the electro-optic Q-switched crystal are coated with a high transmittance film with a laser transmittance greater than 99%.

[0011] The laser assembly includes a main cavity mirror and a gain module, with the gain module located between the main cavity mirror and the polarizer.

[0012] The main cavity mirror's reflective surface is coated with a high-reflectivity film system with a laser reflectivity greater than 99%.

[0013] The gain medium of the gain module is rod-shaped, slab-shaped, or disc-shaped.

[0014] A second λ / 4 waveplate is provided between the gain module and the polarizer.

[0015] The polarizer is set at 45 degrees, and the front surface of the polarizer is coated with a film system that has a transmittance of more than 99% for horizontally polarized lasers and a reflectance of more than 99% for vertically polarized lasers.

[0016] When the electro-optic Q-switching crystal is not powered and the acousto-optic Q-switching crystal is powered, the laser cannot oscillate; when the electro-optic Q-switching crystal is powered, the laser oscillates between the main cavity mirror and the electro-optic cavity mirror.

[0017] When the electro-optic Q-switching crystal is not powered and the acousto-optic Q-switching crystal is powered, the laser cannot oscillate; when neither the electro-optic Q-switching crystal nor the acousto-optic Q-switching crystal is powered, the laser oscillates between the main cavity mirror, the electro-optic cavity mirror, and the acousto-optic cavity mirror.

[0018] The advantages and positive effects of this invention are as follows:

[0019] This invention can operate in both electro-optic Q-switching and acousto-optic Q-switching modes, giving it the advantage of having two operating modes in one laser. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of another embodiment of the present invention.

[0022] The components include: 1. Main cavity mirror; 2. Gain module; 3. Polarizer; 4. First λ / 4 waveplate; 5. Electro-optic Q-switched crystal; 6. Electro-optic cavity mirror; 7. Acousto-optic Q-switched crystal; 8. Acousto-optic cavity mirror; 9. Second λ / 4 waveplate. Detailed Implementation

[0023] The invention will now be described in further detail with reference to the accompanying drawings.

[0024] like Figures 1-2 As shown, the present invention includes a laser assembly, an electro-optic Q-switching assembly, an acousto-optic Q-switching assembly, and a polarizer 3. The polarizer 3 is disposed in the output optical path of the laser assembly. The electro-optic Q-switching assembly is disposed on one side of the polarizer 3, and the acousto-optic Q-switching assembly is disposed on the other side of the polarizer 3. The laser assembly includes a main cavity mirror 1. The electro-optic Q-switching assembly includes an electro-optic Q-switching crystal 5 and an electro-optic cavity mirror 6, with the electro-optic Q-switching crystal 5 disposed between the electro-optic cavity mirror 6 and the polarizer 3. The electro-optic Q-switching crystal 5 is connected to a first power-on module. The acousto-optic Q-switching assembly includes an acousto-optic Q-switching crystal 7 and an acousto-optic cavity mirror 8, with the acousto-optic Q-switching crystal 7 disposed between the polarizer 3 and the acousto-optic cavity mirror 8. The acousto-optic Q-switching crystal 7 is connected to a second power-on module. The first and second power-on modules are known in the art, and the first and second power-on modules are controlled by the same laser system.

[0025] like Figures 1-2 As shown, the electro-optic Q-switching component includes a first λ / 4 waveplate 4, which is disposed between the electro-optic Q-switching crystal 5 and the polarizer 3. When the electro-optic Q-switching crystal 5 is not energized and the acousto-optic Q-switching crystal 7 is energized, the laser cannot oscillate. When the electro-optic Q-switching crystal 5 is energized (the acousto-optic Q-switching crystal 7 can be energized or not), the laser can oscillate between the main cavity mirror 1 and the electro-optic cavity mirror 6, thereby realizing the operation of electro-optic Q-switching mode.

[0026] The electro-optic Q-switching crystal 5 can be any crystal with electro-optic effect, including but not limited to potassium dihydrogen phosphate (KD*P), barium metaborate (BBO), lanthanum gallium silicate (LGS), rubidium titanium oxyphosphate (RTP), lithium niobate (LN), etc.

[0027] The reflective surface of the electro-optic cavity mirror 6 is coated with a high-reflectivity film system with a laser reflectivity greater than 99%, and the light-transmitting surfaces of the first λ / 4 waveplate 4 and the electro-optic Q-switched crystal 5 are coated with a high-transmittance film system with a laser transmittance greater than 99%. Both the reflective and transmittance film systems are technologies known in the art.

[0028] like Figures 1-2 As shown, the acousto-optic Q-switched crystal 7 can be any material with acousto-optic diffraction effect, including but not limited to fused silica, glass, lead molybdate, etc. The reflective surface of the acousto-optic cavity mirror 8 is coated with a high-reflectivity film system with a laser reflectivity greater than 99%, and the light-transmitting surface of the acousto-optic Q-switched crystal 7 is coated with a high-transmittance film system with a laser transmittance greater than 99%.

[0029] like Figures 1-2 As shown, the laser assembly includes a main cavity mirror 1 and a gain module 2, with the gain module 2 positioned between the main cavity mirror 1 and a polarizer 3. The main cavity mirror 1 has a highly reflective coating with a laser reflectivity greater than 99% on its reflective surface. The gain medium of the gain module 2 can be any solid-state laser gain medium, including but not limited to: for example, neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal, ytterbium-doped yttrium aluminum garnet (Yb:YAG) crystal, thulium-doped lithium yttrium fluoride (Tm:YLF) crystal, holmium-doped yttrium vanadate (Ho:YVO4) crystal, erbium-doped yttrium aluminum garnet (Er:YAG) crystal, etc. The gain medium of the gain module 2 can be rod-shaped, slab-shaped, or disc-shaped. The gain module 2 is pumped using side pumping, end-face pumping, or large-area pumping methods.

[0030] like Figure 2 As shown, a second λ / 4 waveplate 9 can be set between the gain module 2 and the polarizer 3 as needed. By adjusting the angle of the λ / 4 waveplate, the output coupling rate of the laser can be adjusted, thereby further optimizing the laser.

[0031] like Figures 1-2 As shown, the polarizer 3 is set at 45 degrees, and the front surface of the polarizer 3 is coated with a film system that has a transmittance of more than 99% for horizontally polarized laser and a reflectance of more than 99% for vertically polarized laser in this state.

[0032] The working principle of this invention is as follows:

[0033] The present invention operates in both electro-optic Q-switching and acousto-optic Q-switching modes, wherein:

[0034] When the electro-optic Q-switching crystal 5 is not powered and the acousto-optic Q-switching crystal 7 is powered, the laser cannot oscillate; when the electro-optic Q-switching crystal 5 is powered (the acousto-optic Q-switching crystal can be powered or not), the laser can oscillate between the main cavity mirror 1 and the electro-optic cavity mirror 6, thereby realizing the operation of electro-optic Q-switching mode.

[0035] When the electro-optic Q-switching crystal 5 is not powered and the acousto-optic Q-switching crystal 7 is powered, the laser cannot oscillate; when the electro-optic Q-switching crystal 5 is not powered and the acousto-optic Q-switching crystal 7 is also not powered, the laser can oscillate between the main cavity mirror 1, the electro-optic cavity mirror 6 and the acousto-optic cavity mirror 8, thus achieving acousto-optic Q-switching operation.

[0036] The following examples further illustrate this point.

[0037] Example 1:

[0038] like Figure 1 As shown: In this embodiment, the gain medium of gain module 2 is an Nd:YAG crystal with an output laser wavelength of 1064nm; the shape of the gain medium of gain module 2 is rod-shaped; the pumping method of gain module 2 is side pumping with a pump light wavelength of 808nm; the electro-optic Q-switching crystal 5 is a BBO crystal; and the acousto-optic Q-switching crystal 7 is fused silica.

[0039] When the electro-optic Q-switching crystal 5 is not energized and the acousto-optic Q-switching crystal 7 is energized, the laser cannot oscillate. When the electro-optic Q-switching crystal 5 is energized (λ / 4 voltage is applied, regardless of whether the acousto-optic Q-switching crystal 7 is energized), the laser can oscillate between the main cavity mirror 1 and the electro-optic cavity mirror 6, achieving electro-optic Q-switching operation. The acousto-optic Q-switching assembly includes the acousto-optic Q-switching crystal 7 and the acousto-optic cavity mirror 8. The acousto-optic Q-switching assembly is located on both sides of the polarizer 3 along the direction of the electro-optic structure. When the electro-optic Q-switching crystal 5 is not energized and the acousto-optic Q-switching crystal 7 is energized, the laser cannot oscillate. When neither the electro-optic Q-switching crystal 5 nor the acousto-optic Q-switching crystal 7 is energized, the laser can oscillate between the main cavity mirror 1, the electro-optic cavity mirror 6, and the acousto-optic cavity mirror 8, achieving acousto-optic Q-switching operation.

[0040] Example 2:

[0041] The difference between this embodiment and embodiment 1 is that a second λ / 4 waveplate 9 is inserted between the gain module 2 and the polarizer 3. By adjusting the angle of the second λ / 4 waveplate, the output coupling rate of the laser can be adjusted, thereby further optimizing the laser.

Claims

1. A Q-switching mode switchable laser, characterized in that: The laser assembly includes a laser component, an electro-optic Q-switching component, an acousto-optic Q-switching component, and a polarizer (3). The polarizer (3) is located on the output optical path of the laser component. The electro-optic Q-switching component is located on one side of the polarizer (3), and the acousto-optic Q-switching component is located on the other side of the polarizer (3). The laser component is equipped with a main cavity mirror (1). The electro-optic Q-switching component includes an electro-optic Q-switching crystal (5) and an electro-optic cavity mirror (6). The electro-optic Q-switching crystal (5) is located between the electro-optic cavity mirror (6) and the polarizer (3). The electro-optic Q-switching crystal (5) is connected to a first power-on module. The acousto-optic Q-switching component includes an acousto-optic Q-switching crystal (7) and an acousto-optic cavity mirror (8). The acousto-optic Q-switching crystal (7) is located between the polarizer (3) and the acousto-optic cavity mirror (8). The acousto-optic Q-switching crystal (7) is connected to a second power-on module. The first power-on module and the second power-on module are controlled by the same laser system; The acousto-optic Q-switching component is located on both sides of the electro-optic Q-switching component along the direction of the electro-optic structure; The electro-optic Q-switching component includes a first λ / 4 waveplate (4), and the first λ / 4 waveplate (4) is disposed between the electro-optic Q-switching crystal (5) and the polarizer (3); When operating in electro-optic Q-switching mode, the laser cannot oscillate when the electro-optic Q-switching crystal (5) is not powered and the acousto-optic Q-switching crystal (7) is powered. When the electro-optic Q-switched crystal (5) is powered on, the laser oscillates between the main cavity mirror (1) and the electro-optic cavity mirror (6); When operating in the acousto-optic Q-switching mode, the laser cannot oscillate when the electro-optic Q-switching crystal (5) is not powered and the acousto-optic Q-switching crystal (7) is powered. When the electro-optic Q-switching crystal (5) is not powered and the acousto-optic Q-switching crystal (7) is also not powered, the laser oscillates between the main cavity mirror (1), the electro-optic cavity mirror (6), and the acousto-optic cavity mirror (8).

2. The Q-switching mode switchable laser according to claim 1, characterized in that: The reflective surface of the electro-optic cavity mirror (6) is coated with a high reflectivity film with a laser reflectivity greater than 99%, and the light-transmitting surfaces of the first λ / 4 waveplate (4) and the electro-optic Q-switched crystal (5) are coated with a high transmittance film with a laser transmittance greater than 99%.

3. The Q-switching mode switchable laser according to claim 1, characterized in that: The laser assembly includes a main cavity mirror (1) and a gain module (2), with the gain module (2) located between the main cavity mirror (1) and the polarizer (3).

4. The Q-switching mode switchable laser according to claim 1 or 3, characterized in that: The main cavity mirror (1) has a reflective surface coated with a high reflectivity film with a laser reflectivity greater than 99%.

5. The Q-switching mode switchable laser according to claim 3, characterized in that: The gain medium of the gain module (2) is rod-shaped, slab-shaped, or disc-shaped.

6. The Q-switching mode switchable laser according to claim 3, characterized in that: A second λ / 4 waveplate (9) is provided between the gain module (2) and the polarizer (3).

7. The Q-switching mode switchable laser according to claim 1, characterized in that: The polarizer (3) is set at 45 degrees, and the front surface of the polarizer (3) is coated with a film system with a transmittance of more than 99% for horizontally polarized laser and a reflectance of more than 99% for vertically polarized laser.

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