Multi-optical-path folding pool SRS ultra-short pulse laser

Abstract

The utility model discloses a multi-optical-path folding pool SRS (Sounding Reference Signal) ultrashort pulse laser. The device comprises a pump light source, an optical isolator, a beam splitter, an SRS unit, a spectroscope, a reflector, a dichroic mirror and an SRS amplification pool. Initial pump light is generated by the pump light source, one-way propagation is guaranteed through the optical isolator, the pump light is divided into two parts through the beam splitter, one part directly enters the SRS unit to generate Stokes light, the other part passes through the delay line and then is emitted to the dichroic mirror, the spectroscope separates the pump light and the Stokes light, the reflector reflects the Stokes light into the SRS amplification pool, the dichroic mirror reflects the pump light to enter the SRS amplification pool, and the SRS amplification pool emits the SRS light. The SRS amplification pool enables the pump light and the Stokes light to be reflected for multiple times in the pool and to be superposed in optical path, so that the high-power Stokes light is obtained. According to the utility model, through the design of the multi-optical-path folding pool, the energy and power of laser pulses are improved, stable output of high-energy and ultra-short pulses is realized, the energy conversion efficiency is optimized, and the energy utilization effect is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of short pulse lasers, in particular to a multi-optical path folding cell SRS ultrashort pulse laser. Background Art

[0002] Existing SRS (stimulated Raman scattering) ultrashort pulse lasers primarily rely on nonlinear optical effects such as self-phase modulation and four-wave mixing to achieve pulse compression. However, the pulse width and energy of these traditional SRS lasers are limited by the gain medium and intracavity optical components, making it difficult to achieve high-energy and ultrashort pulse output. Furthermore, existing SRS ultrashort pulse lasers suffer from low average power and slow processing speeds, limiting their application in high-precision material processing and scientific research. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a multi-path folded cell SRS ultrashort pulse laser to solve the limitations of the existing SRS ultrashort pulse laser in terms of ablation rate, average power, etc. and to improve the energy and power of the laser pulse.

[0004] The utility model solves the above-mentioned technical problem by providing a multi-path folded cell SRS ultrashort pulse laser, comprising a pump light source, an optical isolator, a beam splitter, an SRS unit, a beam splitter, a reflector, a dichroic mirror, and an SRS amplifying cell, wherein:

[0005] The pump light source is used to generate initial pump light;

[0006] The optical isolator is arranged after the pump light source, and is used for the forward transmission of the pump light by isolating the reverse transmission of the pump light at the same time, thereby realizing the unidirectional propagation of the pump light;

[0007] The beam splitter is arranged after the optical isolator and is used to split the pump light into two parts, one part directly enters the SRS unit, and the other part passes through the delay line and is emitted to the dichroic mirror;

[0008] The SRS unit is arranged after the beam splitter and is used to generate Stokes light through the forward SRS effect;

[0009] The spectroscope is arranged after the SRS unit and is used to separate the pump light and the Stokes light;

[0010] The reflector is arranged after the beam splitter and located at one end entrance of the SRS amplification cell, and is used to reflect the Stokes light into the SRS amplification cell;

[0011] The dichroic mirror is arranged after the beam splitter and located at the other end entrance of the SRS amplifying cell, and is used to reflect the pump light into the SRS amplifying cell;

[0012] The SRS amplifying cell is located between the dichroic mirror and the reflecting mirror, and is used to allow the pump light and the Stokes light to meet in the SRS amplifying cell and undergo multiple reflections and optical path superposition.

[0013] As a further improvement of the present technical solution, the optical isolator is composed of a first polarizer P1, a Faraday rotator FR, a quarter-wave plate λ / 4 and a second polarizer P2 which are arranged in sequence according to the propagation direction of light.

[0014] As a further improvement of the present technical solution, the beam splitter is also used to determine the amount of reflected and transmitted energy.

[0015] As a further improvement of the present technical solution, the SRS unit includes a nonlinear optical crystal for generating Stokes light through a forward SRS effect.

[0016] As a further improvement of the present technical solution, a tunable optical delay line is provided between the beam splitter and the dichroic mirror to make the propagation time of the pump light consistent with that of the Stokes light.

[0017] As a further improvement of the present technical solution, both sides of the crystal inside the SRS amplifying cell are coated with a chamfered high-reflectivity film, which can achieve the superposition of optical paths and obtain high-power Stokes light.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. In the multi-path folding cell SRS ultrashort pulse laser, the design of the multi-path folding cell realizes multiple reflections and folding of the laser pulse, effectively improving the problem that traditional SRS short pulse lasers are easily limited by the gain medium and intracavity optical elements, and improving the energy and power of the laser pulse, thereby achieving high-power output, meeting the needs of high-energy lasers in high-precision material processing, and overcoming the shortcomings of existing SRS ultrashort pulse lasers with limited pulse width and energy.

[0020] 2. In the multi-path folded cell SRS ultrashort pulse laser, the pump light and the Stokes light meet in the SRS amplifying cell. Because the crystals inside the SRS amplifying cell are coated with a high-reflectivity film with chamfered corners on both sides, the light can undergo multiple total reflections, which increases the optical path and the interaction time of the two beams of light, thereby optimizing the energy conversion efficiency. Compared with the low heating efficiency and other problems in the existing technology, this has significantly improved the energy utilization effect.

[0021] 3. In the multi-path folding cell SRS ultrashort pulse laser, the multi-path folding cell can achieve precise control and adjustment of the laser pulse, so that it can be flexibly changed according to the needs of different applications, providing a more adaptable laser equipment and expanding the application range of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0023] In the figure, 1. Pump light source; 2. Optical isolator; 3. Beam splitter; 4. SRS unit; 5. Beam splitter; 6. Reflector; 7. Dichroic mirror; 8. SRS amplifying cell. DETAILED DESCRIPTION

[0024] The following are specific examples of the present invention, which are only used to further illustrate the present invention and do not limit the scope of protection of the present invention.

[0025] Example 1

[0026] See also Figure 1 As shown, the purpose of this embodiment is to provide a multi-path folding cell SRS ultrashort pulse laser, including a pump light source 1, an optical isolator 2, a beam splitter 3, an SRS unit 4, a beam splitter 5, a reflector 6, a dichroic mirror 7 and an SRS amplifying cell 8.

[0027] Pump light source 1 uses an Nd:YAG laser. Nd:YAG lasers offer high stability and a long lifespan, making them suitable for long-term continuous operation and providing stable pump light for the subsequent SRS process. The wavelength and power of this pump light can be selected based on specific application requirements. For example, for certain high-precision material processing applications, a pump light source 1 with a wavelength of 1064nm and a power of 10W can be selected. An optical isolator 2 is positioned after pump light source 1. This forward-propagating pump light is isolated from the reverse-propagating pump light, ensuring unidirectional propagation of the pump light. Optical isolator 2 consists of a first polarizer P1, a Faraday rotator FR, a quarter-wave plate λ / 4, and a second polarizer P2, arranged in the order of light propagation. This combination effectively isolates the reverse-propagating light, ensuring the safe and stable operation of pump light source 1.

[0028] The beam splitter 3 is arranged after the optical isolator 2 and is used to split the pump light into two parts. The reflection and transmission ratio of the beam splitter 3 can be set to 9:1, that is, one-tenth of the energy passes through the beam splitter 3 and nine-tenths of the energy is reflected. Part of the pump light that passes through the beam splitter 3 directly enters the SRS unit 4, while the reflected part passes through the delay line and is emitted to the dichroic mirror 7. The introduction of the delay line is to adjust the propagation time of the pump light so that it is consistent with the propagation time of the Stokes light generated by the SRS unit 4, ensuring that the two meet in the SRS amplification cell 8. The delay line can be implemented by adjusting the length of the optical fiber or using a tunable optical delay line to ensure that the propagation time difference between the two beams is less than 1ns.

[0029] The SRS unit 4 is located after the beam splitter 3 and is used to generate Stokes light through the forward SRS effect. The SRS unit 4 includes a nonlinear optical crystal, such as a potassium dihydrogen phosphate (KDP) crystal, which can effectively generate Stokes light with high conversion efficiency. The Stokes light generated by the SRS unit 4 passes through the beam splitter 5, which is used to separate the pump light and the Stokes light. The design of the beam splitter 5 enables the pump light and Stokes light to be effectively separated, with a separation efficiency of over 95%.

[0030] Reflector 6 is positioned after beam splitter 5 and at one entrance to the SRS amplifying cell 8. It is used to reflect the Stokes light into the SRS amplifying cell 8. Reflector 6 is made of a high-reflectivity material, with a reflectivity of up to 99.9%, ensuring maximum reflection efficiency for the Stokes light. Dichroic mirror 7 is positioned after beam splitter 3 and at the other entrance to the SRS amplifying cell 8. It is used to reflect the pump light into the SRS amplifying cell 8 and transmit unwanted Stokes light. The design of dichroic mirror 7 ensures that the pump light is reflected to the greatest extent possible into the SRS amplifying cell 8, with a reflectivity of up to 98%, while the Stokes light passes through the dichroic mirror 7 with a transmittance of up to 95%.

[0031] The SRS amplifying cell 8 is located between the dichroic mirror 7 and the reflector 6, and is used to allow the pump light and Stokes light to meet in the SRS amplifying cell 8 and undergo multiple reflections and optical path superposition, thereby obtaining high-power Stokes light. The crystals inside the SRS amplifying cell 8 are coated with a high-reflectivity film with chamfered corners on both sides, allowing the light to undergo multiple total reflections, up to 10 times or more, with the reflectivity of each reflection exceeding 99.9%. This design not only increases the optical path, but also extends the interaction time of the pump light and Stokes light in the SRS amplifying cell 8, thereby optimizing the energy conversion efficiency. Experimental data show that through the design of a multi-optical path folding cell, the conversion efficiency of the SRS amplifying cell 8 can be increased by more than 20%, and the power of the Stokes light finally obtained can reach 50mJ, with a pulse width of 10ps, meeting the needs of high-precision material processing and scientific research.

[0032] Example 2

[0033] This embodiment provides a multi-optical path folded cell SRS ultrashort pulse laser, the basic structure of which is the same as that of embodiment 1, but with some details optimized and improved.

[0034] First, the wavelength and power of pump light source 1 can be adjusted according to specific application requirements. For example, for processing certain specific materials, a pump light source 1 with a wavelength of 532 nm and a power of 20 W can be selected. This choice better matches the material's absorption characteristics, improving processing efficiency and quality.

[0035] Secondly, the ratio of beam splitter 3 can be adjusted according to actual needs. For example, for certain applications requiring higher Stokes light intensity, the reflection-to-transmission ratio of beam splitter 3 can be adjusted to 8:2, meaning that one-fifth of the energy passes through beam splitter 3, and four-fifths is reflected. This adjustment increases the pump light energy passing through SRS unit 4, thereby improving the intensity of the Stokes light. Experimental data shows that when the ratio of beam splitter 3 is adjusted to 8:2, the power of the resulting Stokes light can be increased by more than 15%.

[0036] Furthermore, the high-reflectivity coating on both sides of the crystal within the SRS amplification cell 8 can be further optimized. For example, an anti-reflection coating can be added to the high-reflectivity coating to reduce reflection losses and improve light transmission efficiency. Experimental data shows that adding the anti-reflection coating can further increase the reflectivity of the SRS amplification cell 8 to 99.95%, achieve over 12 reflections, and ultimately achieve a Stokes light power of 60 mJ while maintaining a pulse width of 10 ps.

[0037] Example 3

[0038] This embodiment provides a multi-optical path folded cell SRS ultrashort pulse laser, the basic structure of which is the same as that of Embodiment 1 and Embodiment 2, but is further optimized in certain application scenarios.

[0039] First, the choice of pump light source 1 can be adjusted according to the specific application scenario. For example, for certain applications that require long-term continuous operation, a semiconductor laser with high stability and long life can be selected as the pump light source 1. This choice can ensure the stability and reliability of the laser during long-term operation.

[0040] Secondly, the size and shape of the SRS amplification cell 8 can be adjusted to meet actual needs. For example, for applications requiring high energy density, the SRS amplification cell 8 can be designed as a cylinder with a diameter of 10 cm and a length of 30 cm. This design increases the volume of the SRS amplification cell 8, lengthening the optical path length and thereby further improving the power of the Stokes light. Experimental data shows that when the SRS amplification cell 8 is resized to a cylindrical shape, the resulting Stokes light power can reach 70 mJ, while maintaining a pulse width of 10 ps.

[0041] Furthermore, to further enhance the cooling efficiency of the SRS amplification cell 8, a water cooling device can be installed on its outer wall. The cooling water flow rate of the water cooling device is 1L / min and the temperature is maintained at 20°C. This device effectively removes heat generated within the SRS amplification cell 8, ensuring the long-term stable operation of the laser. Experimental data shows that the addition of the water cooling device can reduce the temperature of the SRS amplification cell 8 by more than 10°C, further improving the stability and reliability of the laser.

[0042] Any matters not described in this utility model are applicable to the prior art.

Claims

1. A multi-path folded cell SRS ultrashort pulse laser, characterized by: The invention comprises a pump light source (1), an optical isolator (2), a beam splitter (3), an SRS unit (4), a beam splitter (5), a reflector (6), a dichroic mirror (7), and an SRS amplifying cell (8), wherein: The pump light source (1) is used to generate initial pump light; The optical isolator (2) is arranged after the pump light source (1), and is used for the forward-transmitted pump light to achieve unidirectional propagation of the pump light by isolating the reverse-transmitted pump light at the same time; The beam splitter (3) is arranged after the optical isolator (2) and is used to split the pump light into two parts, one part directly entering the SRS unit (4), and the other part passing through the delay line and then projecting towards the dichroic mirror (7); The SRS unit (4) is arranged after the beam splitter (3) and is used to generate Stokes light through the forward SRS effect; The spectroscope (5) is arranged after the SRS unit (4) and is used to separate the pump light and the Stokes light; The reflector (6) is arranged after the beam splitter (5) and is located at one end entrance of the SRS amplifying cell (8), and is used to reflect the Stokes light into the SRS amplifying cell (8); The dichroic mirror (7) is arranged after the beam splitter (3) and is located at the other end entrance of the SRS amplifying cell (8), and is used to reflect the pump light into the SRS amplifying cell (8); The SRS amplifying cell (8) is located between the dichroic mirror (7) and the reflecting mirror (6), and is used to allow the pump light and the Stokes light to meet in the SRS amplifying cell (8) and to undergo multiple reflections and optical path superposition.

2. The multi-path folded cell SRS ultrashort pulse laser according to claim 1, characterized in that: The optical isolator (2) consists of a first polarizer P1, a Faraday rotator FR, a quarter-wave plate λ / 4, and a second polarizer P2, which are arranged in sequence according to the propagation direction of light.

3. The multi-path folded cell SRS ultrashort pulse laser according to claim 1, characterized in that: The beam splitter (3) is also used to determine the amount of reflected and transmitted energy.

4. The multi-path folded cell SRS ultrashort pulse laser according to claim 1, characterized in that: The SRS unit (4) includes a nonlinear optical crystal for generating Stokes light through a forward SRS effect.

5. The multi-path folded cell SRS ultrashort pulse laser according to claim 1, characterized in that: A tunable optical delay line is provided between the beam splitter (3) and the dichroic mirror (7) for aligning the propagation time of the pump light with that of the Stokes light.

6. The multi-path folded cell SRS ultrashort pulse laser according to claim 5, characterized in that: Both sides of the crystal inside the SRS amplifying cell (8) are coated with a chamfered high reflectivity film.

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