CN-114204395-B - Stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser

CN114204395BCN 114204395 BCN114204395 BCN 114204395BCN-114204395-B

Abstract

The invention relates to a stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser, which comprises a pumping source, an optical isolation system, a half wave plate, a first polaroid, an SBS pulse width compression system with adjustable pulse width, a first reflecting mirror and an SRS generation amplification system, wherein a single longitudinal mode laser is used as the pumping source to emit pumping light, and the pumping light sequentially passes through the optical isolation system, the half wave plate and the first polaroid and then enters the SBS pulse width compression system; the pump light is compressed into hundred picosecond laser in the SBS pulse width compression system, and the compressed hundred picosecond laser is reflected by the first polarizer and the first reflector and then enters the SRS generation amplification system for further compression and amplification. The technical scheme of combined compression of the SBS pulse width compression technology and the SRS pulse width compression technology overcomes the limitation of compression limit of the SBS pulse width compression technology, and achieves laser pulse width output with narrower pulse width than the Q-switching technology and higher energy than the mode locking technology.

Inventors

LIU ZHAOHONG
LI SHAOWEN
LUO TIANTIAN
FAN RONG
JI WENQIANG
CHEN TINGTING
WANG YULEI
LV ZHIWEI

Assignees

河北工业大学
河北工业大学

Dates

Publication Date: 20260421
Application Date: 20220113
Priority Date: 20220113

Claims (8)

1. The stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser comprises a pumping source, an optical isolation system, a half wave plate, a first polaroid and an SBS pulse width compression system with adjustable pulse width, and is characterized by further comprising a first reflecting mirror and an SRS generation amplifying system, The single longitudinal mode laser is used as a pumping source to emit pumping light, and the pumping light sequentially passes through the optical isolation system, the half wave plate and the first polaroid and then enters the SBS pulse width compression system; The SRS generation amplifying system is used for realizing pulse width compression of the hundred picoseconds light generated by the SBS pulse width compression system, and comprises a beam splitter, a second reflector, a third reflector, a narrow-band filter, an SRS generation tank, a first dichroic mirror, a first SRS amplifying tank and a second dichroic mirror, wherein the hundred picoseconds laser generated by the SBS pulse width compression system enters the SRS generation amplifying system and is split by the beam splitter, one beam is reflected by the first dichroic mirror and is emitted into the SRS generation tank, forward stimulated Raman scattering occurs in the SRS generation tank, the Stokes seed light for generating forward transmission passes through the narrow-band filter, is reflected by the third reflector and is emitted into the first SRS amplifying tank through the first dichroic mirror, the other beam is reflected by the second reflector and the second dichroic mirror and enters the first SRS amplifying tank and meets the opposite direction of the Stokes seed light, and as the two beams meet the SRS phase matching condition, the Stokes seed light can extract the energy of the hundred picoseconds laser and finally is emitted by the second dichroic mirror; the first dichroic mirror and the second dichroic mirror are high in light transmittance of the forward first-order Stokes seeds and high in reflection of the hundred picosecond lasers; The SRS generation pool adopts a forward SRS seed generation-based method, and the position of the first SRS amplification pool needs to ensure that the process of meeting and amplifying the hundred picosecond laser and Stokes seed light is in a Raman medium; the SRS generation and amplification system generates forward Raman, a focusing lens is not used, crystal damage is avoided, and the influence of high-order Stokes light is reduced; The output range of SBS is required to meet the requirement between the damage threshold and the Raman threshold, an active amplifier is not required to amplify the laser pulse, and high-energy laser pulse output can be generated only through the SBS pulse width compression system and the SRS generation amplification system, so that ultra-short compression of SBS pulse width from subnanosecond to subpicosecond, picosecond and tens of picoseconds is realized.
2. The stimulated brillouin scattering and stimulated raman scattering combined compressed ultrashort pulse laser device according to claim 1, further comprising a fourth reflecting mirror, a second SRS amplifying pool and a third dichroic mirror, wherein the unconsumed hundred picosecond laser and the once amplified Stokes seed light are subjected to second amplification and compression through deflection of an optical path to obtain higher energy conversion efficiency, the Stokes seed light output by the second dichroic mirror enters the second SRS amplifying pool through the fourth reflecting mirror and the fourth reflecting mirror, the hundred picosecond laser coming out of the second dichroic mirror is reflected to the third dichroic mirror through the first dichroic mirror, then reflected to the second SRS amplifying pool to meet the Stokes seed light in an opposite mode again, the second amplification and compression are performed, and finally high-energy picosecond laser is output.
3. The stimulated brillouin scattering and stimulated raman scattering combined compressed ultrashort pulse laser of claim 2, wherein the pool medium of the SRS generation pool and the two SRS amplification pools selects a raman active medium having an optical phonon lifetime on the order of picoseconds.
4. The stimulated brillouin scattering and stimulated raman scattering combined compressed ultra-short pulse laser of claim 3, wherein the raman-active medium is one of Ba (NO 3 ) 2 、H 2 、NH 3 、CS 2 ).
5. The stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser device is characterized in that an optical isolation system consists of a second polaroid, a Faraday rotator and a third polaroid, an SBS pulse width compression system consists of a quarter wave plate, an SBS pulse width compression pool, a TEC refrigerating plate, a temperature control module and a concave reflecting mirror, a pumping source generates single longitudinal mode pumping light to sequentially pass through the isolation system to prevent returning light from damaging a resonant cavity, the pumping light is converted into circular polarized light through the half wave plate, the first polaroid and the quarter wave plate and then generates an SBS pulse width compression effect in the SBS pulse width compression pool to compress the pumping light to the hundred picosecond level, the temperature in the SBS pulse width compression pool is controlled through adjusting the TEC refrigerating plate and the temperature control module, so that the output pulse width is adjustable, the outputted hundred picosecond laser is reversely transmitted, an optical path is separated by the first polaroid, and the pumping light is returned to enter an SRS generating amplification system through the first reflecting mirror.
6. The stimulated brillouin scattering and stimulated raman scattering combined compressed ultrashort pulse laser of claim 5, wherein the pool medium of the SBS pulse width compression pool adopts a liquid heavy fluorocarbon series medium with a large phonon life and gain coefficient changing range with temperature, and is one of FC-72, FC-77, FC-87, FC-84, FC-70 and FC-770.
7. The stimulated brillouin scattering and stimulated raman scattering combined compressed ultrashort pulse laser of claim 5, wherein in a liquid medium, phonon lifetime of the medium decreases with decreasing temperature, narrowing of an output pulse is achieved by cooling the medium, and meanwhile, the medium temperature is controlled to be changed into a pulse-adjustable output light source, so that output pulse width of an SRS generating amplification system is controlled to be adjustable, and narrowing of a final output pulse is achieved.
8. The stimulated brillouin scattering and stimulated raman scattering combined compression ultrashort pulse laser according to claim 5, wherein a device with high temperature adjustment precision is selected by a TEC refrigerating chip so as to perform more accurate pulse width adjustment, the temperature adjustment range is-30-130 ℃, the adjustment temperature cannot be higher than the boiling point of a medium in a used SBS pulse width compression pool, and in order to obtain a more ideal output pulse width, the output pulse width of a pulse width adjustable SBS pulse width compression system is below 2 ns.

Description

Stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser Technical Field The invention relates to the technical field of high-energy short pulse laser, in particular to a stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser. Background The ultra-short pulse laser has wide application in the fields of impact dynamics, laser precise ranging, ultra-long distance laser radar, laser medical instruments, laser micro-machining and the like, and particularly has important significance for promoting industrial machining and leading edge science. At present, there are three main methods for obtaining short pulse laser (1) Q-switched technology, which can obtain subnanosecond short pulse laser by shortening the cavity length and combining travelling wave amplification to obtain subnanosecond high-energy laser (as disclosed in patent publication No. CN110880672B, patent name: a high-repetition-frequency high-energy nanosecond pulse laser and a using method thereof), but the method can not obtain shorter pulse any more, (2) mode-locked technology, which can obtain femtosecond to picosecond ultra-short ultra-fast pulse, but the generated pulse energy is smaller, usually in the order of nano-to micro-focal, and the subsequent amplification is more complicated (as disclosed in patent publication No. CN101562310, patent name: passive mode-locked picosecond laser), and (3) stimulated scattering pulse width compression technology, which can compress nanosecond pulse to the order of hundred picosecond, usually by stimulated Brillouin scattering (Stimulated Brillouin Scattering, SBS), but is limited by physical limits, and can not obtain ultra-short ultra-fast pulse laser. The method combines the SBS and stimulated Raman scattering (Stimulated RAMAN SCATTERING, SRS) compression technology, combines the high energy conversion efficiency of the SBS and the short compression limit of the SRS, can effectively generate high-energy ultrashort pulse laser, has a simple structure and low cost, has strong engineering applicability, and is a very effective technology for generating high-energy ultrashort pulses. Disclosure of Invention The invention provides a stimulated Brillouin scattering and stimulated Raman scattering combined compression ultrashort pulse laser, which overcomes the limitation of the compression limit of an SBS pulse width compression technology by adopting the technical scheme of combining and compressing the SBS pulse width compression technology and an SRS pulse width compression technology, achieves the pulse width narrower than a Q-switching technology and the pulse width output of laser with higher energy than a mode locking technology, and simultaneously realizes continuous adjustment of pulse width by introducing a temperature control system. The stimulated Brillouin scattering and stimulated Raman scattering combined compressed ultrashort pulse laser comprises a pumping source 1, an optical isolation system 2, a half wave plate 3, a first polaroid 4 and an SBS pulse width compression system 5 with adjustable pulse width, and is characterized by further comprising a first reflecting mirror 6 and an SRS generation amplifying system 7, The single longitudinal mode laser is used as a pumping source 1 to emit pumping light, the pumping light sequentially passes through an optical isolation system 2, a half wave plate 3 and a first polaroid 4 and then enters an SBS pulse width compression system 5, the pumping light is compressed into hundred picosecond laser in the SBS pulse width compression system 5, and the compressed hundred picosecond laser is reflected by the first polaroid 4 and a first reflecting mirror 6 and then enters an SRS generating and amplifying system 7 for further compression and amplification. The SRS generation amplification system 7 is used for realizing pulse width compression of the hundred picoseconds light generated by the SBS pulse width compression system 5, the SRS generation amplification system 7 comprises a beam splitter 7-1, a second reflector 7-2, a third reflector 7-3, a narrowband filter 7-4, an SRS generation tank 7-5, a first dichroic mirror 7-6, a first SRS amplification tank 7-7 and a second dichroic mirror 7-8, the hundred picoseconds laser generated by the SBS pulse width compression system 5 enters the SRS generation amplification system 7 and is split by the beam splitter 7-1, one beam is reflected by the first dichroic mirror 7-6 and enters the SRS generation tank 7-5, forward stimulated raman scattering occurs in the SRS generation tank 7-5, the Stokes seed light generated to be transmitted forward is transmitted through the narrowband filter 7-4 and is transmitted through the first dichroic mirror 7-6 after being reflected by the third reflector 7-3, the other beam is transmitted through the first dichroic mirror 7-6 and enters the first SRS amplification tank 7-7 a