One-way two-stage amplification device based on picosecond laser

Abstract

The utility model relates to the technical field of picosecond laser amplification, and particularly discloses a one-way two-stage amplification device based on picosecond laser. Comprising a picosecond seed source, a first shaping system, an aperture diaphragm, a first pumping source, a first waveguide coupling module, a first lath crystal, a second pumping source, a second waveguide coupling module, a second lath crystal, a total reflective mirror, a second shaping system and a focusing lens, the aperture diaphragm is located between the first shaping system and the first lath crystal, a square light transmitting hole is formed in the middle of the aperture diaphragm, and compared with the prior art, the device has the advantages that laser with high energy, narrow pulse width and good stability can be output, and amplified picosecond laser can meet application requirements of more fields.

Description

Technical Field

[0001] The utility model relates to the technical field of picosecond laser amplification, in particular to a device based on single-pass two-stage amplification of picosecond laser. Background Art

[0002] In many application fields of lasers, such as laser ranging, remote sensing detection, precision industrial processing, and microelectronics fields, lasers are generally required to have high peak power, high pulse energy, and high beam quality at the same time. Therefore, the seed source must be amplified to meet the application requirements. Especially in the field of laser micromachining, picosecond lasers in the joule level have the characteristics of small thermal action range, high precision, and high speed. However, such lasers can only obtain laser pulse outputs in the microjoule level. To obtain laser outputs with millijoule or even greater energy, the picosecond seed laser is usually amplified to achieve high-energy laser outputs.

[0003] In a solid-state laser, the pump light is coupled into the laser gain medium through end-pumping or side-pumping. Due to the quantum deficit effect, the energy absorbed by the laser crystal cannot be completely converted into laser output. A part of the energy is converted into heat, forming a temperature distribution field inside the crystal, resulting in unbalanced temperature and stress distribution at different positions inside the crystal. The light passing through the crystal generates a phase difference, causing the crystal to generate a thermal effect, which has a huge impact on the laser output power, beam quality, optical-optical conversion efficiency, and power stability.

[0004] Therefore, it is necessary to propose a device based on single-pass two-stage amplification of picosecond laser to reduce the thermal effect of the laser crystal. Content of the Utility Model

[0005] The purpose of the utility model is to solve the problem that the crystal in the existing picosecond laser amplification device generates a thermal effect, thereby affecting the laser output power, beam quality, optical-optical conversion efficiency, and power stability. A device based on single-pass two-stage amplification of picosecond laser is provided.

[0006] The technical solution of the utility model is as follows:

[0007] A device based on single-pass two-stage amplification of picosecond laser.

[0008] A device based on single-pass two-stage amplification of picosecond laser includes a picosecond seed source, a first shaping system, an aperture stop, a first pump source, a first waveguide coupling module, a first slab crystal, a second pump source, a second waveguide coupling module, a second slab crystal, a total reflection mirror, a second shaping system, and a focusing lens;

[0009] The picosecond seed source can generate picosecond seed light. The aperture stop is located between the first shaping system and the first slab crystal, and a square light-transmitting hole is opened in the middle of the aperture stop;

[0010] The first pump source can generate first pump light, and the first waveguide coupling module refracts the first pump light onto the lateral large surface of the first slab crystal. The second pump source can generate second pump light, and the second waveguide coupling module refracts the second pump light onto the lateral large surface of the second slab crystal;

[0011] The first slab crystal can absorb the first pump light to generate laser light and amplify the passing picosecond seed light. The second slab crystal can absorb the second pump light to generate laser light and amplify the passing picosecond seed light;

[0012] The total reflection mirror can reflect the amplified laser light. The shaping system can shape the picosecond seed light to achieve mode matching of the spot size between the picosecond seed light and the amplification stage. The focusing lens can focus the amplified laser light.

[0013] Further, both the first pump source and the second pump source are laser diode bar arrays, which pump the lateral large surfaces of the first slab crystal and the second slab crystal from the side. The wavelength of the laser diode pump light is 808 nm, and the average power is 50 W.

[0014] Further, both the first slab crystal and the second slab crystal are laser crystals with linearly polarized radiation properties, and their model is Nd:YAG.

[0015] Further, both the first slab crystal and the second slab crystal are non-isosceles trapezoid shapes and are both horizontally placed. There is a wedge angle difference of 2° between the two crystal end faces of the first slab crystal and the second slab crystal.

[0016] Further, both the first pump source and the second pump source are connected with circulating cooling water.

[0017] Further, both the first slab crystal and the second slab crystal are connected with circulating cooling water.

[0018] Further, both the aperture diaphragm and the total reflection mirror are coated with a high reflection film of 1064 nm, and the focusing lens is coated with an antireflection film of 1064 nm.

[0019] Further, both the first slab crystal and the second slab crystal are coated with a seed light antireflection film and a pump light antireflection film.

[0020] Further, the shaping system includes a first negative lens, a first positive lens, a second negative lens, and a second positive lens arranged in sequence. The first negative lens and the first positive lens expand and shape the seed light in the x-z plane direction, and the second negative lens and the second positive lens expand and shape the seed light in the x-y plane direction, so as to make the picosecond seed light match the spot mode of the amplification stage.

[0021] A device based on picosecond laser single - pass two - stage amplification of the present utility model uses a first slab crystal and a second slab crystal to perform two - stage amplification on picosecond laser, improving the amplification gain of picosecond seed light; the method of using side - pumped slab crystals can reduce the thermal lens effect and improve the utilization rate of the gain medium. The structure is simple and compact. Compared with traditional technologies, the device of the present utility model can output high - energy, narrow - pulse - width, and stable laser, enabling the amplified picosecond laser to meet the application requirements of more fields. Brief Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the present utility model;

[0023] Figure 2 is a schematic diagram of the basic principles of the first shaping system and the second shaping system of the present utility model;

[0024] Figure 3 is a schematic diagram of the process of converting a circular light spot into a square light spot through an aperture stop in the present utility model.

[0025] Reference Numerals: 1, picosecond seed source; 2, first shaping system; 3, aperture stop; 4, first pump source; 5, first waveguide coupling module; 6, first slab crystal; 7, second pump source; 8, second waveguide coupling module; 9, second slab crystal; 10, total - reflection mirror; 11, focusing lens; 12, second shaping system. Detailed Embodiments

[0026] In order to make the technical means, technical features, utility model purpose, and technical effects achieved by the present utility model easy to understand, the present utility model will be further described below with reference to specific drawings.

[0027] Embodiment 1:

[0028] As Figure 1 shown, this embodiment provides a device based on picosecond laser single - pass two - stage amplification, including a picosecond seed source 1, a first shaping system 2, an aperture stop 3, a first pump source 4, a first waveguide coupling module 5, a first slab crystal 6, a second pump source 7, a second waveguide coupling module 8, a second slab crystal 9, a total - reflection mirror 10, a second shaping system 12, and a focusing lens 11.

[0029] The picosecond seed source 1 is located at the injection end of the first shaping system 2 and is used to generate picosecond seed light and inject it into the first shaping system 2; the first shaping system 2 is used for shaping the picosecond seed light to achieve mode matching with the spot size of the amplification stage; as Figure 3As shown, the aperture diaphragm 3 is located between the first shaping system 2 and the first slab crystal 6. The middle hole is square, used to limit the fundamental mode radius. The first pump source 4 and the second pump source 7 are both used to generate pump light. The first waveguide coupling module 5 and the second waveguide coupling module 8 are used to shape and homogenize the pump light and couple the pump light into the large side surfaces of the first slab crystal 6 and the second slab crystal 9 respectively. The first slab crystal 6 and the second slab crystal 9 are used to absorb the pump light to generate laser, and at the same time amplify the injected picosecond seed light. The total reflection mirror 10 is used to reflect the amplified laser. The second shaping system 12 is used to shape the amplified laser. The focusing lens 11 is used to focus the amplified laser.

[0030] As Figure 1 shown, the optical transmission light path of the device of the present utility model is as follows:

[0031] The picosecond seed light output by the picosecond seed source 1, after being shaped and collimated by the first shaping system 2, is injected into the aperture diaphragm 3, changing the circular light spot into a square light spot, and then incident into the first slab crystal 6. After the seed light is amplified by the first slab crystal 6, it enters the second slab crystal 9 for secondary amplification, and finally passes through the reflection of the total reflection mirror 10, and is shaped by the second shaping system 12 and focused by the focusing lens 11 for output.

[0032] During the transmission of the picosecond seed light, the pump light of the first pump source 4 passes through the first waveguide coupling module 5, making the focal spot coincide with the seed light focal spot inside the first slab crystal 6; the pump light of the second pump source 7 passes through the second waveguide coupling module 8, making the focal spot coincide with the seed light focal spot inside the second slab crystal 9. Under the continuous pumping of the first pump source 4 and the second pump source 7, the picosecond seed light obtains gain from the first slab crystal 6 and the second slab crystal 9, so as to be amplified.

[0033] In specific implementation, both the first pump source 4 and the second pump source 7 are laser diode bar arrays, both side-pumping the large side surfaces of the first slab crystal 6 and the second slab crystal 9. The central wavelength of the laser diode pump light is 808 nm, and the average power is 50 W. Both the first pump source 4 and the second pump source 7 are connected with circulating cooling water.

[0034] In specific implementation, both the first slab crystal 6 and the second slab crystal 9 are non-isosceles trapezoid shapes, made of Nd:YAG, horizontally placed. And in order to prevent the generation of self-excited oscillation, there is a 2° wedge angle difference at both crystal end faces of the first slab crystal and the second slab crystal. The crystal end faces are coated with an antireflection film for picosecond seed light, the large pump side of the crystal is coated with an antireflection film for pump light, and the other side is coated with a high-reflection film for pump light. Both the first slab crystal 6 and the second slab crystal 9 are connected with circulating cooling water.

[0035] In specific implementation, the aperture diaphragm 3 and the total reflection mirror 10 are both coated with a high reflection film of 1064 nm, and the focusing lens 11 is coated with an antireflection film of 1064 nm.

[0036] As Figure 1 and Figure 2 shown, the first shaping system includes a first negative lens, a first positive lens, a second negative lens, and a second positive lens arranged in sequence. The first negative lens and the first positive lens expand and shape the seed light in the x-z plane direction, and the second negative lens and the second positive lens expand and shape the seed light in the x-y plane direction, so as to match the spot mode of the picosecond seed light with that of the amplification stage. The x-y plane and the x-z plane refer to the x-y-z planes in the space coordinate system.

[0037] In summary, the above are only the preferred embodiments of the present invention and are not used to limit the implementation scope of the present invention. That is, all equivalent changes and modifications made to the content within the scope of the patent application of the present invention shall fall within the technical scope of the present invention.

Claims

1. A device based on picosecond laser single-pass two-stage amplification, characterized in that: It includes a picosecond seed source (1), a first shaping system (2), an aperture diaphragm (3), a first pump source (4), a first waveguide coupling module (5), a first slab crystal (6), a second pump source (7), a second waveguide coupling module (8), a second slab crystal (9), a total reflection mirror (10), a second shaping system (12) and a focusing lens (11); The picosecond seed source (1) can generate picosecond seed light. The aperture diaphragm (3) is located between the first shaping system (2) and the first slab crystal (6), and a square light-transmitting hole is provided in the middle of the aperture diaphragm (3); The first pump source (4) can generate first pump light. The first waveguide coupling module (5) refracts the first pump light to the side large surface of the first slab crystal (6). The second pump source (7) can generate second pump light. The second waveguide coupling module (8) refracts the second pump light to the side large surface of the second slab crystal (9); The first slab crystal (6) can absorb the first pump light to generate laser and amplify the passing picosecond seed light. The second slab crystal (9) can absorb the second pump light to generate laser and amplify the passing picosecond seed light; The total reflection mirror (10) can reflect the amplified laser. The shaping system can shape the picosecond seed light to achieve the mode matching of the spot size of the picosecond seed light and the amplification stage. The focusing lens (11) can focus the amplified laser.

2. The device based on picosecond laser single-pass two-stage amplification according to claim 1, characterized in that: Both the first pump source (4) and the second pump source (7) are laser diode bar arrays, which pump the side large surfaces of the first slab crystal (6) and the second slab crystal (9) from the side. The wavelength of the laser diode pump light is 808 nm, and the average power is 50 W.

3. The device based on picosecond laser single-pass two-stage amplification according to claim 1, wherein: Both the first slab crystal (6) and the second slab crystal (9) are laser crystals with linearly polarized radiation properties, and their model is Nd:YAG.

4. The device based on picosecond laser single-pass two-stage amplification according to claim 1, characterized in that: Both the first slab crystal (6) and the second slab crystal (9) are non-isosceles trapezoid shapes and are both horizontally placed. There is a wedge angle difference of 2° between the two crystal end faces of the first slab crystal (6) and the second slab crystal (9).

5. The device based on picosecond laser single-pass two-stage amplification according to claim 1, wherein: Both the first pump source (4) and the second pump source (7) are connected with circulating cooling water.

6. The device based on picosecond laser single-pass two-stage amplification according to claim 1, wherein: Both the first slab crystal (6) and the second slab crystal (9) are connected with circulating cooling water.

7. The device based on picosecond laser single-pass two-stage amplification according to claim 1, wherein: Both the aperture diaphragm (3) and the total reflection mirror (10) are coated with a high reflection film of 1064 nm, and the focusing lens (11) is coated with an anti-reflection film of 1064 nm.

8. The device based on picosecond laser single-pass two-stage amplification according to claim 1, characterized in that: Both the first slab crystal (6) and the second slab crystal (9) are coated with a seed light anti-reflection film and a pump light anti-reflection film.

9. The device based on picosecond laser single-pass two-stage amplification according to claim 1, characterized in that: The first shaping system (2) includes a first negative lens, a first positive lens, a second negative lens, and a second positive lens arranged in sequence. The first negative lens and the first positive lens expand and shape the seed light in the x-z plane direction. The second negative lens and the second positive lens expand and shape the seed light in the x-y plane direction, so as to make the picosecond seed light match the spot mode of the amplification stage.

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