The hundreds of picosecond laser device of high-energy based on stimulated Brillouin scattering Pulse Compression
Technical field
The present invention relates to the laser based on stimulated Brillouin scattering (SBS) Pulse Compression, belong to optical instrument field.
Background technology
In a lot of industry and research application, such as high-precision range laser radar, laser spot-eliminating beauty treatment, laser marking, laser processing etc., require that laser pulse has a series of exacting terms such as laser pulse width (hundreds of psec) narrow as far as possible, higher pulse energy (hundreds of millijoule ~ joule magnitude), repetition work (>10Hz), high-peak power, single longitudinal mode.At present, the pulse laser of extensive use mainly contains two classes, and a class is mode-locked laser, the laser pulse width that such laser exports is femtosecond or the ultrashort pulse being less than tens psecs, is characterized in that single pulse energy is very low, only has millijoule magnitude, the live width of laser is very wide, and coherence is poor; Another kind of pulse laser is Q-switched laser, the laser pulse width that such laser exports is nanosecond order, be characterized in that single pulse energy is higher, but because pulse duration is wider, the peak power of pulse is lower, and in laser spot-eliminating beauty treatment application, in order to reduce wound, wish that laser pulse is more narrow better.Therefore, be necessary to develop a kind of output laser pulse width in hundreds of psec, pulse energy is in joule magnitude, can with the narrow linewidth laser of repetition rate work, to meet the application demand in the fields such as increasing high-precision laser range-finding radar, laser spot-eliminating beauty treatment, laser marking, laser processing.
Summary of the invention
The present invention seeks to the problem that can not realize the output of burst pulse high-energy single longitudinal mode in order to solve existing laser, providing the hundreds of picosecond laser device of a kind of high-energy based on stimulated Brillouin scattering Pulse Compression.
The hundreds of picosecond laser device of high-energy based on stimulated Brillouin scattering Pulse Compression of the present invention, it comprises oscillator, beam expanding telescope, polarizer, faraday isolator, 45 ° of rotors, No. two polarizers, laser amplifier, 90 ° of rotors, No. two laser amplifiers, quarter wave plate, plane mirror, No. two plane mirrors and a stimulated Brillouin scattering generation unit;
Polarizer, faraday isolator, 45 ° of rotors and No. two polarizers form light shielding system along optical axis arrangement successively;
The p polarised light that oscillator produces is after beam expanding telescope, transmitted through light shielding system, the p polarised light of transmission first amplifies through a laser amplifier, s polarised light is become again through 90 ° of rotors, described s polarised light is converted into circularly polarized light through quarter wave plate after No. two laser amplifiers amplify further, enters stimulated Brillouin scattering generation unit produce stimulated Brillouin scattering by a plane mirror and No. two plane mirror continuous reflection after changing direction successively; The Guang Yanyuan of the Stokes dorsad road produced by stimulated Brillouin scattering generation unit returns, direction is changed successively through No. two plane mirrors, a plane mirror continuous reflection, p polarised light is converted into through quarter wave plate, this p polarised light becomes s polarised light through 90 ° of rotors after No. two laser amplifiers amplify, and this s polarised light is separated by No. two polarizers and reflects light path after a laser amplifier amplifies further.
Advantage of the present invention:
(1) single pulse energy of this laser output is far away higher than traditional mode-locked laser, can reach a joule magnitude;
(2) pulse duration that this laser exports is less than traditional Q-switched laser, can export hundred psecs or hundreds of psec pulsewidth;
(3) this laser is while output short pulse, maintains the narrow linewidth of laser;
(4) make use of the phase conjugation characteristic of stimulated Brillouin scattering, the dynamic phasing caused due to heat when compensate for the static phase distortion and laser repetition work that cause in the optical component course of processing in the middle of light path distorts, ensure that laser can be greater than the repetition rate work of 10Hz, the beam quality exported;
(5) compared with traditional SBS pulse compression, introduce two-stage laser amplifier, the laser pulse after compression, by the amplification of laser amplifier, can realize the Energy transmission of joule magnitude;
(6) laser amplifier MOPA system, is fully extracted the energy storage in amplifier, improves the efficiency of laser.
Accompanying drawing explanation
Fig. 1 is the structural representation of the hundreds of picosecond laser device of the high-energy based on stimulated Brillouin scattering Pulse Compression of the present invention;
Fig. 2 is three kinds of structural representations of stimulated Brillouin scattering generation unit.
Embodiment
Embodiment one: present embodiment is described below in conjunction with Fig. 1, based on the hundreds of picosecond laser device of the high-energy of stimulated Brillouin scattering Pulse Compression described in present embodiment, it comprises oscillator 1, beam expanding telescope 2, polarizer 3, faraday isolator 4,45 ° of rotors 5, No. two polarizers 6, laser amplifier 7,90 ° of rotors 8, No. two laser amplifiers 9, quarter wave plate 10, plane mirror 11, No. two plane mirrors 12 and stimulated Brillouin scattering generation unit 13;
Polarizer 3, faraday isolator 4,45 ° of rotors 5 and No. two polarizers 6 form light shielding system along optical axis arrangement successively;
The p polarised light that oscillator 1 produces is after beam expanding telescope 2, transmitted through light shielding system, the p polarised light of transmission first amplifies through a laser amplifier 7, s polarised light is become again through 90 ° of rotors 8, described s polarised light is converted into circularly polarized light through quarter wave plate 10 after No. two laser amplifiers 9 amplify further, enters stimulated Brillouin scattering generation unit 13 produce stimulated Brillouin scattering by a plane mirror 11 and No. two plane mirror 12 continuous reflection after changing direction successively; The Guang Yanyuan of the Stokes dorsad road produced by stimulated Brillouin scattering generation unit 13 returns, direction is changed successively through No. two plane mirrors 12, plane mirror 11 continuous reflection, p polarised light is converted into through quarter wave plate 10, this p polarised light becomes s polarised light through 90 ° of rotors 8 after No. two laser amplifiers 9 amplify, and this s polarised light is separated by No. two polarizers 6 and reflects light path after a laser amplifier 7 amplifies further.
Oscillator 1 adopts wavelength to be 1064nm or 1053nm.
The wavelength exported based on the hundreds of picosecond laser device of the high-energy of stimulated Brillouin scattering Pulse Compression described in present embodiment is at about 1000nm.
Embodiment two: present embodiment is described below in conjunction with Fig. 2, present embodiment is described further execution mode one, stimulated Brillouin scattering generation unit 13 adopts single pool structure, stimulated Brillouin scattering generation unit 13 is made up of convex lens and Brillouin's medium pool, incident light planoconvex lens is focused into and is mapped to Brillouin's medium pool, in Brillouin's medium pool, the near focal point of convex lens produces stimulated Brillouin scattering, and Stokes Guang Yuan road returns dorsad.As shown in Fig. 2 (a).
The length of Brillouin's medium pool selects 50cm ~ 120cm, and focal length of convex lens is 20cm ~ 100cm.Brillouin's medium pool internal diameter selects 20mm ~ 50mm, and Brillouin's medium refraction index of the liquid of Brillouin's medium pool inside selects between 1.2 ~ 1.5, and phonon lifetime is selected between 100ps ~ 500ps.
The liquid of Brillouin's medium pool inside is FC-72, FC-77, FC-87, FC-84, FC-70 or water H
2one in O.
Embodiment three: present embodiment is described below in conjunction with Fig. 2, present embodiment is described further execution mode one, stimulated Brillouin scattering generation unit 13 adopts compact pair of pool structure, stimulated Brillouin scattering generation unit 13 is made up of convex lens and two Brillouin's medium pools, in two Brillouin's medium pools, one is amplification pond, another is for producing pond, incident light through amplification pond after by convex lens focus to produce pond, in generation pond, the near focal point of convex lens produces stimulated Brillouin scattering, Stokes light returns through amplifying amplification Hou Yanyuan road, pond dorsad.As shown in Fig. 2 (b).
The length of Brillouin's medium pool selects 50cm ~ 120cm, and focal length of convex lens is 20cm ~ 100cm.Brillouin's medium pool internal diameter selects 20mm ~ 50mm, and Brillouin's medium refraction index of the liquid of Brillouin's medium pool inside selects between 1.2 ~ 1.5, and phonon lifetime is selected between 100ps ~ 500ps.
The liquid of Brillouin's medium pool inside is FC-72, FC-77, FC-87, FC-84, FC-70 or water H
2one in O.
Embodiment four: present embodiment is described below in conjunction with Fig. 2, present embodiment is described further execution mode one, stimulated Brillouin scattering generation unit 13 adopts non-focusing structure, stimulated Brillouin scattering generation unit 13 is made up of Brillouin's medium pool and a concave mirror, incident light returns Brillouin's medium pool through after Brillouin's medium pool by the concave mirror focus after this Brillouin's medium pool, produce stimulated Brillouin scattering, gained dorsad Stokes Guang Yanyuan road returns.As shown in Fig. 2 (c).
The length of Brillouin's medium pool selects 50cm ~ 120cm, and concave mirror focal length is 20cm ~ 100cm.Brillouin's medium pool internal diameter selects 20mm ~ 50mm, and Brillouin's medium refraction index of the liquid of Brillouin's medium pool inside selects between 1.2 ~ 1.5, and phonon lifetime is selected between 100ps ~ 500ps.
The liquid of Brillouin's medium pool inside is FC-72, FC-77, FC-87, FC-84, FC-70 or water H
2one in O.