Nanosecond laser regenerative amplifier with adjustable pulse width

Abstract

The utility model discloses a nanosecond laser regenerative amplifier with adjustable pulse width. The nanosecond laser regenerative amplifier comprises a seed source, a collimation and optoisolator, a regenerative amplifier and an electric control system, the electric control system is respectively connected with the seed source and the regenerative amplifier, the seed source is used for outputting seed laser, the seed laser is incident into the regenerative amplifier after passing through the collimator and the optical isolator, and the regenerative amplifier is used for carrying out gain amplification on the seed laser and outputting the seed laser. According to the utility model, the semiconductor laser is used as a seed source, so that the pulse width of the output laser can be continuously adjusted, and the problem that the pulse width of the traditional seed source cannot be adjusted is solved; the method provides possibility for laser application in the scientific research, medical treatment and industrial fields such as fluorescence lifetime imaging, laser-induced breakdown spectroscopy, laser surface treatment, laser processing, laser annealing, terahertz generation and the like.

Description

Technical Field

[0001] The utility model belongs to the field of electronic information technology, and particularly relates to a nanosecond laser regenerative amplifier with adjustable pulse width. Background Art

[0002] Nanosecond laser amplifiers usually use solid-state lasers or fiber lasers with Q-switching technology as seed sources. As a laser itself, the seed source also requires a semiconductor laser as a pump source. At the same time, since the Q-switching technology cannot control the pulse energy and repetition frequency of the output laser, additional attenuation and selection are required in subsequent amplification, which increases the cost of the laser and reduces its stability.

[0003] The Q-switching technology used in nanosecond laser amplifiers can be divided into two categories: active Q-switching and passive Q-switching. For high-energy nanosecond lasers, lasers with passive Q-switching technology are usually used as seed sources. The passive Q-switching technology can generate pulse sequences with pulse widths below 10 ns, but the laser pulse width cannot be adjusted arbitrarily, which limits its application in some fields.

[0004] With the maturity of semiconductor lasers and their electrical drive technology, it has become possible to directly output semiconductor lasers with a central wavelength of 1064 nm and an arbitrary pulse width below 10 ns. Using such semiconductor lasers as the seed source of the amplifier has the advantages of continuously adjustable pulse width, simple structure, and low cost, and can achieve a more compact laser design. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a nanosecond laser regenerative amplifier with adjustable pulse width in view of the deficiencies of the prior art.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] A nanosecond laser regenerative amplifier with adjustable pulse width includes a seed source, a collimator and optical isolator, a regenerative amplifier, and an electronic control system;

[0008] The electronic control system is respectively connected to the seed source and the regenerative amplifier. The seed source is used to output seed laser, which is incident on the regenerative amplifier after passing through the collimator and optical isolator. The regenerative amplifier is used to amplify the gain of the seed laser and output it.

[0009] A further improvement of the utility model is that the seed source is a semiconductor laser.

[0010] A further improvement of the present utility model lies in that the collimator and optical isolator include a collimating coupling head, an isolator, and a reflecting mirror; the collimating coupling head is used to convert the seed light in the optical fiber into parallel spatial light, the optical isolator is used to prevent the backward light of the regenerative amplifier from damaging the seed source 1, and the reflecting mirror group is used to adjust the injection direction of the seed laser.

[0011] A further improvement of the present utility model lies in that the regenerative amplifier includes a pump source, a gain medium, a pump coupling head, a dichroic mirror, a first curved mirror, a second curved mirror, a third curved mirror, a fourth curved mirror, a plane mirror, a first thin film polarizer, a second thin film polarizer, and a Pockels cell;

[0012] The pump source is used to pump the gain medium, the gain medium is used to absorb the laser of the pump source and amplify the seed light; the pump coupling head is used to convert the laser output by the pump source into a focused beam and incident on the gain medium; the dichroic mirror is located between the gain medium and the pump coupling head and is used to incident the pump light on the gain medium; the plane mirror is used to optimize the spatial size of the laser; the first to fourth curved mirrors are used to form a resonant cavity; the first thin film polarizer and the second thin film polarizer are used to output the amplified laser; the Pockels cell is used for final cavity dumping to achieve amplified laser output.

[0013] A further improvement of the present utility model lies in that the pump source is a fiber-coupled semiconductor laser, and its central wavelength is the same as the absorption of the gain medium.

[0014] A further improvement of the present utility model lies in that the surface of the dichroic mirror is coated with a dielectric film that is highly reflective to laser and highly transmissive to pump light.

[0015] A further improvement of the present utility model lies in that the surface of the plane mirror is coated with a dielectric film that is highly reflective to laser.

[0016] A further improvement of the present utility model lies in that the first to fourth curved mirrors are a series of concave or convex reflecting mirrors with different curvatures, and their surfaces are all coated with a dielectric film that is highly reflective to laser.

[0017] A further improvement of the present utility model lies in that the surfaces of the first thin film polarizer and the second thin film polarizer are coated with a dielectric film that is highly reflective to horizontally polarized laser and highly transmissive to vertically polarized laser.

[0018] The present utility model at least has the following beneficial technical effects:

[0019] The present utility model uses a semiconductor laser as the seed source, realizes continuous adjustment of the output laser pulse width, overcomes the problem of non-adjustable pulse width of the traditional seed source, and provides possibilities for laser applications in scientific research, medical, and industrial fields such as fluorescence lifetime imaging, laser-induced breakdown spectroscopy, laser surface treatment, laser processing, laser annealing, and terahertz generation. [[ID=*]]

[0020] The present utility model uses a semiconductor laser as a pump source. Compared with the traditional solid seed source, it also has the advantages of simple structure, high reliability, and low cost. It can achieve a more compact design of the regenerative amplifier and can reduce the cost of the regenerative amplifier. Description of the Drawings

[0021] Figure 1 It is a circuit diagram of a nanosecond laser regenerative amplifier with adjustable pulse width according to the present utility model.

[0022] Figure 2 It is a schematic structural diagram of the regenerative amplifier according to the present utility model.

[0023] Description of the Reference Numerals in the Drawings:

[0024] 1. Seed source; 2. Collimator and optical isolator; 3. Regenerative amplifier; 4. Electric control system;

[0025] 301. Pump source; 302. Gain medium; 303. Pump coupling head; 304. Dichroic mirror; 305. First curved mirror; 306. Second curved mirror; 307. Third curved mirror; 308. Fourth curved mirror; 309. Plane mirror; 310. First thin film polarizer; 311. Second thin film polarizer; 312. Pockels cell. Detailed Embodiments

[0026] Hereinafter, exemplary embodiments of the present utility model will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present utility model can be more thoroughly understood and the scope of the present utility model can be completely conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other. Hereinafter, the present utility model will be described in detail with reference to the drawings and in combination with the embodiments.

[0027] As Figure 1 shown, a nanosecond laser regenerative amplifier with adjustable pulse width provided by the present utility model includes a seed source 1, a collimator and optical isolator 2, a regenerative amplifier 3, and an electric control system 4, which are composed of 4 parts in total.

[0028] Among them, the seed source 1 is a semiconductor laser, the output pulse width of which can be adjusted within a certain range, and its central wavelength can also be set to match the emission peak of the gain medium in the regenerative amplifier 3 by adjusting the working temperature. Its repetition frequency can be adjusted within a certain range. The seed laser is output to the outside after being coupled through a single-mode polarization-maintaining fiber.

[0029] The collimator and optical isolator 2 consists of a collimating coupling head, an isolator, and a mirror group. Among them, the collimating coupling head is used to convert the seed light in the optical fiber into parallel spatial light, the optical isolator is used to prevent the backward light of the regenerative amplifier 3 from damaging the seed source 1, and the mirror group is used to adjust the injection direction of the seed laser. Through the collimator and optical isolator 2, the seed is injected into the regenerative amplifier 3, and the backward light of the regenerative amplifier is prevented from damaging the seed source 1.

[0030] The structure of the regenerative amplifier 3 is as Figure 2 shown, and the lines in the figure represent the distribution of light rays in the laser. The regenerative amplifier 3 consists of a pump source 301, a gain medium 302, a pump coupling head 303, a dichroic mirror 304, a first curved mirror 305, a second curved mirror 306, a third curved mirror 307, a fourth curved mirror 308, a plane mirror 309, a first thin-film polarizer 310, a second thin-film polarizer 311, a Pockels cell 312, etc. Among them, the pump source 301 is also a fiber-coupled semiconductor laser, whose central wavelength is the same as the absorption of the gain medium 302, and is used to pump the gain medium 302. The gain medium 302 is used to absorb the laser of the pump source 301 and amplify the seed light. The pump coupling head 303 is used to convert the laser output by the pump source 301 into a focused beam and incident on the gain medium 302. The dichroic mirror 304 is located between the gain medium 302 and the pump coupling head 303, and its surface is coated with a dielectric film with high reflectivity for laser and high transmittance for pump light, and is used to incident the pump light on the gain medium 302. The plane mirror 309 has a dielectric film with high reflectivity for laser coated on its surface, and is used to optimize the spatial size of the laser. The first curved mirror 305 to the fourth curved mirror 308 are a series of concave or convex mirrors with different curvatures, and their surfaces are all coated with a dielectric film with high reflectivity for laser, and are used to form a resonant cavity. The first thin-film polarizer 310 and the second thin-film polarizer 311 are used to output the amplified laser, and their surfaces are coated with a dielectric film with high reflectivity for horizontally polarized laser and high transmittance for vertically polarized laser. The Pockels cell 312 is the core device of the regenerative amplifier, and is used for final cavity dumping to achieve amplified laser output.

[0031] The electronic control system 4 consists of an LDDH-xxAyyV-MA series LD driver board produced by Shenzhen Xiafan Optoelectronic Technology Co., Ltd., a QDCxxx-yyW-zz series end-pumped Q driver, a TCB-NE series temperature control board, and a PPC-01A pulse picking control board. The electronic control system 4 is respectively connected to the seed source 1 and the regenerative amplifier 3. It provides signals such as current, pulse width, repetition frequency, and enable for the seed source 1, thereby controlling the output of the seed source, and at the same time receives the pulse signal of the seed light from the seed source as a reference signal. There is a synchronous delay device inside it, which is used to provide a delay signal. It provides signals such as output power, gate width, and repetition frequency for the regenerative amplifier, thereby controlling the output of the pump source of the regenerative amplifier and the opening and closing of the Pockels cell.

[0032] When the utility model works, the seed laser output by the seed source 1 is incident into the regenerative amplifier 3 after passing through the collimator and optical isolator 2, and is amplified multiple times through the gain medium in the regenerative amplifier 3. Finally, the amplified laser is output through the Pockels cell of the regenerative amplifier 3 under the control of the electronic control system 4, and the amplified laser is finally realized.

[0033] Through the control of the seed source 1 by the electronic control system 4, arbitrary adjustment of the pulse width and repetition frequency of the seed laser can be achieved, thereby realizing the output of nanosecond regenerative amplified laser with adjustable pulse width.

[0034] The utility model has the following advantages:

[0035] 1. Use a semiconductor laser as the seed source of the regenerative amplifier;

[0036] 2. Use a semiconductor laser as the seed source to achieve continuous adjustment of the pulse width, adjustable repetition frequency, etc.

[0037] Although the utility model has been described in detail with general descriptions and specific implementation schemes in the above text, based on the utility model, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the utility model all fall within the scope of protection required by the utility model.

Claims

1. A nanosecond laser regenerative amplifier with adjustable pulse width, characterized in that, It includes a seed source, a collimator and optical isolator, a regenerative amplifier, and an electronic control system; The electronic control system is respectively connected to the seed source and the regenerative amplifier. The seed source is used to output seed laser, which is incident on the regenerative amplifier after passing through the collimator and optical isolator. The regenerative amplifier is used to amplify the seed laser by gain and output it.

2. The nanosecond laser regenerative amplifier with adjustable pulse width according to claim 1, characterized in that, The seed source is a semiconductor laser.

3. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 1, characterized in that, The collimator and optical isolator include a collimating coupling head, an isolator, and a mirror group; the collimating coupling head is used to convert the seed light in the optical fiber into parallel spatial light, the optical isolator is used to prevent the backward light of the regenerative amplifier from damaging the seed source (1), and the mirror group is used to adjust the injection direction of the seed laser.

4. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 1, characterized in that, The regenerative amplifier includes a pump source, a gain medium, a pump coupling head, a dichroic mirror, a first curved mirror, a second curved mirror, a third curved mirror, a fourth curved mirror, a plane mirror, a first thin-film polarizer, a second thin-film polarizer, and a Pockels cell; The pump source is used to pump the gain medium, and the gain medium is used to absorb the laser of the pump source and amplify the seed light; the pump coupling head is used to convert the laser output by the pump source into a focused beam and incident on the gain medium; the dichroic mirror is located between the gain medium and the pump coupling head and is used to incident the pump light on the gain medium; the plane mirror is used to optimize the spatial size of the laser; the first to fourth curved mirrors are used to form a resonant cavity; the first thin-film polarizer and the second thin-film polarizer are used to output the amplified laser; the Pockels cell is used for final cavity dumping to achieve the output of the amplified laser.

5. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 4, characterized in that, The pump source is a fiber-coupled semiconductor laser, and its central wavelength is the same as the absorption of the gain medium.

6. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 4, characterized in that The surface of the dichroic mirror is coated with a dielectric film that is highly reflective to laser and highly transmissive to pump light.

7. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 4, characterized in that, The surface of the plane mirror is coated with a dielectric film that is highly reflective to laser.

8. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 4, characterized in that, The first to fourth curved mirrors are a series of concave or convex mirrors with different curvatures, and their surfaces are all coated with a dielectric film that is highly reflective to laser.

9. A nanosecond laser regenerative amplifier with adjustable pulse width according to claim 4, characterized in that, The surfaces of the first thin-film polarizer and the second thin-film polarizer are coated with a dielectric film that is highly reflective to horizontally polarized laser and highly transmissive to vertically polarized laser.

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