Ultra-short and ultra-strong pulse laser generation method and device

Abstract

The invention relates to an ultra-short and ultra-strong pulse laser generation method and device, and belongs to the technical field of ultra-short pulse laser, and the ultra-short and ultra-strong pulse laser generation method comprises the steps: S100, dividing pulse laser output by a laser into two paths, and respectively taking the two paths as signal light and pump light; s200, performing optical parametric amplification and light splitting on the pump light and the signal light in a near-degenerate collinear mode to generate amplified signal light and idler frequency light; s300, the amplified signal light and idler frequency light are subjected to pulse compression and then spectrum beam combination, and ultra-short and ultra-strong pulse laser is output. The technical problem that in the prior art, the energy conversion efficiency in the optical parameter amplification process is low can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrashort pulse lasers, and in particular relates to a method and a device for generating ultrashort and ultra-intense pulse lasers. Background Art

[0002] Ultrashort and ultraintense pulse lasers have always been one of the goals pursued by the development of laser technology. The core technical problem to be solved in generating ultrashort and ultraintense pulse lasers is how to compress more laser energy into a narrower time width. Chirped pulse amplification technology is a milestone in the development history of ultrashort and ultraintense pulse laser technology. Ultrashort pulse lasers with high peak power are obtained by broadening, amplifying and compressing ultrashort pulse seed sources. Optical parametric chirped pulse amplification technology replaces the energy level-type gain medium in the traditional chirped pulse amplification system with a nonlinear crystal, effectively improving the signal-to-noise ratio of ultrashort pulses and avoiding the gain narrowing effect of the chirped pulse amplification system, providing an important direction for the development of ultrashort and ultraintense pulse lasers.

[0003] Optical parametric amplification is a three-wave nonlinear process. When a weak signal light and a strong pump light are incident on a nonlinear crystal at the same time, the two beams are coupled through the nonlinear polarization of the medium. In this process, energy is transferred from the strong pump light to the weak signal light, and a beam of idler light is generated at the same time. Excluding the idler light, the "net" energy conversion efficiency from pump light to signal light is η s =f max ×ω s ω p , f max is the pump light conversion efficiency in the optical parametric amplification process, and its theoretical upper limit is 1. s and ω p are the angular frequencies of the signal light and the pump light, respectively. If the wavelength of the signal light is 800nm ​​and the wavelength of the pump light is 527nm, then η s The theoretical limit of η is 66.5%. s The typical value is only about 25%, which is much smaller than the theoretical value (see Wang Jing, "Research on Optical Parametric Noise in Chirped Pulse Amplification Environment", Shanghai Jiao Tong University). Therefore, how to improve the energy conversion efficiency of the optical parametric amplification process is a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0004] In view of various deficiencies in the prior art, a method and device for generating ultrashort and ultraintense pulse lasers are proposed to solve the technical problem of low energy conversion efficiency in the optical parametric amplification process in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a method for generating ultrashort and ultraintense pulse lasers, comprising the following steps:

[0007] S100, the pulse laser output by the laser is divided into two paths, which are used as signal light and pump light respectively;

[0008] S200, the pump light and the signal light are optically parametrically amplified and split in a nearly degenerate collinear manner to generate amplified signal light and idler light;

[0009] S300, the amplified signal light and the idler light are pulse compressed and then spectrally combined to output ultrashort and ultra-intense pulse laser.

[0010] The technical solution is further configured such that in step S100, the pulse laser output by the laser is split after being amplified to form two sub-pulse lasers, one of which is used as signal light after being compressed and generating a supercontinuum spectrum, and the other is used as pump light after being amplified, compressed and frequency-doubled.

[0011] The technical solution is further configured such that the amplified pulse laser is split using a spectroscope.

[0012] The technical solution is further configured such that, in step S200, when the pump light and the signal light are subjected to optical parametric amplification in a nearly degenerate collinear manner, type I phase matching or type II phase matching is adopted, and the posture of the nonlinear crystal in the optical parametric amplification is regulated so that the wavelength of the generated idle light is close to that of the amplified signal light, and the spectra of the two do not overlap, so as to realize light splitting.

[0013] The technical solution is further configured such that the output light beam after optical parametric amplification is split by a dichroic mirror.

[0014] The technical solution is further configured such that, in step S300, the amplified signal light is pulse compressed using a negative chirp mirror, and the idler light is pulse compressed using a positive chirp mirror.

[0015] The technical solution is further configured that, in step S300, when the amplified signal light and the idler light are spectrally combined, the carrier-envelope phase and relative delay of the two are detected and controlled.

[0016] In a second aspect, the present invention provides an ultrashort and ultra-intense pulse laser generating device, comprising:

[0017] A laser, used for outputting pulsed laser light, wherein the pulsed laser light is divided into two paths, serving as signal light and pump light respectively;

[0018] A nonlinear crystal, which is located on the transmission optical path of the pump light and the signal light, wherein the pump light and the signal light are subjected to optical parametric amplification and light splitting in a nearly degenerate collinear manner to generate amplified signal light and idler light;

[0019] A negative chirp mirror, located on the transmission optical path of the amplified signal light, and performing pulse compression on the amplified signal light;

[0020] a positive chirp mirror, located on a transmission optical path of the idler light, and performing pulse compression on the idler light;

[0021] And a spectrum combiner, which is located on the transmission optical path of the amplified signal light and the idler light, performs spectrum combining on the amplified signal light and the idler light to output ultrashort and ultra-intense pulse laser.

[0022] The technical solution is further configured such that the pulse laser is first transmitted to the first energy amplifier, and then divided into two sub-pulse lasers by a spectroscope, one of which is transmitted in sequence to the first pulse compressor and the nonlinear medium as signal light, and the other sub-pulse laser is transmitted in sequence to the second energy amplifier, the second pulse compressor, and the frequency doubling crystal as pump light.

[0023] The technical solution is further configured such that a delay adjustment module is provided on the transmission optical path of the signal light or the pump light.

[0024] The beneficial effects of the present invention are:

[0025] By making full use of the idle light discarded during optical parametric amplification, the energy conversion efficiency of optical parametric amplification is effectively improved. Theoretically, the energy conversion efficiency can reach 100%, and ultrashort and ultra-intense pulse lasers with shorter pulse width and higher peak power can be generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method for generating ultrashort and ultraintense pulse lasers in an embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of the spectrum of the amplified signal light and idler light in an embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of an ultrashort and ultraintense pulse laser generating device in an embodiment of the present invention;

[0029] Figure 4 is a schematic diagram of the transmission of pump light to the delay adjustment module in an embodiment of the present invention;

[0030] Figure 5 It is a schematic diagram of signal light transmission to the delay adjustment module in an embodiment of the present invention.

[0031] In the attached figure: 1. laser; 2. first energy amplifier; 3. spectroscope; 4. first pulse compressor; 5. nonlinear medium; 6. second energy amplifier; 7. second pulse compressor; 8. frequency doubling crystal; 9. nonlinear crystal; 10. dichroic mirror; 11. negative chirp mirror; 12. positive chirp mirror; 13. spectral combiner; 14. beam combiner mirror; 15. delay adjustment module. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional words used are used to illustrate rather than limit the invention.

[0033] According to an embodiment of the present invention, a method for generating ultrashort and ultra-intense pulse laser is provided. Figure 1 , including the following steps:

[0034] S100, the pulse laser output by the laser is divided into two paths, which are used as signal light and pump light respectively;

[0035] S200, the pump light and the signal light are optically parametrically amplified and split in a nearly degenerate collinear manner to generate amplified signal light and idler light;

[0036] S300, the amplified signal light and the idler light are pulse compressed and then spectrally combined to output ultrashort and ultra-intense pulse laser.

[0037] It should be noted that making full use of the idle light discarded during optical parametric amplification can effectively improve the energy conversion efficiency of optical parametric amplification. Based on the law of conservation of energy, the energy conversion efficiency can theoretically reach 100%, and ultrashort and ultra-intense pulse lasers with shorter pulse width and higher peak power can be generated.

[0038] In the method for generating ultrashort and ultraintense pulse laser in this embodiment, please refer to Figure 1 In step S100, the pulse laser output by the laser is amplified and then split to form two sub-pulse lasers. One sub-pulse laser is used as signal light after compression and supercontinuum spectrum generation, and the other sub-pulse laser is used as pump light after amplification, compression and frequency doubling.

[0039] It should be noted that the pulsed laser output by the laser is split after amplification. One beam is used as signal light after compression and supercontinuum spectrum generation, which increases the spectral range of the signal light and is conducive to generating pulses with shorter pulse width; the other beam is used as pump light after amplification, compression and frequency doubling, which increases the energy of the pump light and is conducive to improving the pulse energy after optical parametric amplification.

[0040] In the method for generating ultrashort and ultraintense pulse laser in this embodiment, please refer to Figure 1 The amplified pulse laser is split by a spectroscope.

[0041] In the method for generating ultrashort and ultraintense pulse laser in this embodiment, please refer to Figure 1 , Figure 2 In step S200, when the pump light and the signal light are subjected to optical parametric amplification in a nearly degenerate collinear manner, type I phase matching or type II phase matching is adopted, and the posture of the nonlinear crystal in the optical parametric amplification is regulated so that the wavelength of the generated idle light is close to that of the amplified signal light, and the spectra of the two do not overlap, so as to realize light splitting.

[0042] It should be noted that when the wavelength of the idler light and the amplified signal light are the same, the splitting operation cannot be realized. On the contrary, when the wavelength difference between the two is large, the spectral beam combining effect is poor. Therefore, by adjusting the posture of the nonlinear crystal in the optical parametric amplification, the wavelength of the idler light and the amplified signal light are made close to each other, which is convenient for the splitting operation. The wavelength difference between the two is related to the performance of the optical element for splitting. Specifically, when the output light beam after optical parametric amplification is split by a dichroic mirror, the wavelength difference between the idler light and the amplified signal light can be 10nm. In addition, the closeness here can also be understood as a small overlap of the wavelengths of the two, and this small overlap only exists in the area with weak light intensity.

[0043] In the method for generating ultrashort and ultraintense pulse laser in this embodiment, please refer to Figure 1 In step S300, the amplified signal light is pulse compressed using a negative chirp mirror, and the idler light is pulse compressed using a positive chirp mirror.

[0044] It should be noted that the chirp directions of the amplified signal light and idler light are opposite, so chirped mirrors need to be designed separately.

[0045] In the method for generating ultrashort and ultraintense pulse laser in this embodiment, please refer to Figure 1 In step S300, when the amplified signal light and the idler light are spectrally combined, the carrier-envelope phase and relative delay of the two are detected and controlled.

[0046] According to an embodiment of the present invention, an ultrashort ultra-intense pulse laser generating device is provided. Figure 3 ,include:

[0047] Laser 1, used for outputting pulsed laser, wherein the pulsed laser is divided into two paths, serving as signal light and pump light respectively;

[0048] A nonlinear crystal 9, which is located on the transmission optical path of the pump light and the signal light, and the pump light and the signal light are optically parametrically amplified and split in a nearly degenerate collinear manner to generate amplified signal light and idler light;

[0049] A negative chirp mirror 11, which is located on the transmission optical path of the amplified signal light and performs pulse compression on the amplified signal light;

[0050] a positive chirp mirror 12, which is located on the transmission optical path of the idler light and performs pulse compression on the idler light;

[0051] And a spectrum combiner 13, which is located on the transmission optical path of the amplified signal light and the idler light, performs spectrum combining on the amplified signal light and the idler light to output ultrashort and ultra-intense pulse laser.

[0052] In the ultrashort ultra-intense pulse laser generating device of this embodiment, please refer to Figure 3 The pulse laser is first transmitted to the first energy amplifier 2, and then divided into two sub-pulse lasers by the spectroscope 3. One sub-pulse laser is sequentially transmitted to the first pulse compressor 4 and the nonlinear medium 5 as signal light, and the other sub-pulse laser is sequentially transmitted to the second energy amplifier 6, the second pulse compressor 7, and the frequency doubling crystal 8 as pump light.

[0053] Preferably, the laser 1 is a femtosecond oscillator.

[0054] In the ultrashort and ultra-intense pulse laser generating device of the present embodiment, a delay adjustment module is provided on the transmission optical path of the signal light or the pump light.

[0055] See also Figure 4 The signal light is transmitted by the beam combiner 14, and the pump light is reflected by the beam combiner 14 after passing through the delay adjustment module 15. The two light enter the nonlinear crystal 9 in a colinear manner for near-degenerate optical parametric amplification.

[0056] See also Figure 5 After the signal light passes through the delay adjustment module 15, it is transmitted by the beam combiner 14, and the pump light is reflected by the beam combiner 14. The two light enter the nonlinear crystal 9 in a colinear manner for near-degenerate optical parametric amplification.

[0057] Specifically, the delay adjustment module 15 is composed of two reflectors, and the delay control is achieved by adjusting the positions of the reflectors.

[0058] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A method for generating ultrashort and ultraintense pulse lasers, characterized in that: The following steps are involved: S100, the pulse laser output by the laser is divided into two paths, which are used as signal light and pump light respectively; S200, the pump light and the signal light are optically parametrically amplified and split in a nearly degenerate collinear manner to generate amplified signal light and idler light; S300, the amplified signal light and the idler light are pulse compressed and then spectrally combined to output ultrashort and ultra-intense pulse laser.

2. The method for generating ultrashort and ultraintense pulse laser according to claim 1, characterized in that: In step S100, the pulse laser output by the laser is amplified and then split to form two sub-pulse lasers. One sub-pulse laser is used as signal light after compression and supercontinuum spectrum generation, and the other sub-pulse laser is used as pump light after amplification, compression and frequency doubling.

3. The method for generating ultrashort and ultraintense pulse laser according to claim 2, characterized in that: The amplified pulse laser is split by a spectroscope.

4. The method for generating ultrashort and ultraintense pulse laser according to claim 1, characterized in that: In step S200, when the pump light and the signal light are subjected to optical parametric amplification in a nearly degenerate collinear manner, type I phase matching or type II phase matching is adopted, and the posture of the nonlinear crystal in the optical parametric amplification is regulated so that the wavelength of the generated idle light is close to that of the amplified signal light, and the spectra of the two do not overlap, so as to realize light splitting.

5. The method for generating ultrashort and ultraintense pulse laser according to claim 4, characterized in that: The output beam after optical parametric amplification is split by a dichroic mirror.

6. The method for generating ultrashort and ultraintense pulse laser according to claim 1, characterized in that: In step S300, the amplified signal light is pulse compressed using a negative chirp mirror, and the idler light is pulse compressed using a positive chirp mirror.

7. The method for generating ultrashort and ultraintense pulse laser according to claim 1, characterized in that: In step S300, when the amplified signal light and the idler light are spectrally combined, the carrier-envelope phase and relative delay of the two are detected and controlled.

8. A device for realizing the method for generating ultrashort and ultraintense pulse laser according to any one of claims 1 to 7, characterized in that: include: A laser, used for outputting pulsed laser light, wherein the pulsed laser light is divided into two paths, serving as signal light and pump light respectively; A nonlinear crystal, which is located on the transmission optical path of the pump light and the signal light, wherein the pump light and the signal light are subjected to optical parametric amplification and light splitting in a nearly degenerate collinear manner to generate amplified signal light and idler light; A negative chirp mirror, located on the transmission optical path of the amplified signal light, and performing pulse compression on the amplified signal light; a positive chirp mirror, located on a transmission optical path of the idler light, and performing pulse compression on the idler light; And a spectrum combiner, which is located on the transmission optical path of the amplified signal light and the idler light, performs spectrum combining on the amplified signal light and the idler light to output ultrashort and ultra-intense pulse laser.

9. The ultrashort and ultra-intense pulse laser generating device according to claim 8, characterized in that: The pulse laser is first transmitted to the first energy amplifier, and then divided into two sub-pulse lasers by a spectroscope. One sub-pulse laser is sequentially transmitted to the first pulse compressor and the nonlinear medium as signal light, and the other sub-pulse laser is sequentially transmitted to the second energy amplifier, the second pulse compressor, and the frequency doubling crystal as pump light. 10 . The ultrashort and ultra-intense pulse laser generating device according to claim 8 , wherein a delay adjustment module is provided on the transmission optical path of the signal light or the pump light.

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