阅读说明：本技术 一种高功率高重复频率百皮秒激光器 (High-power high-repetition-frequency hundred picosecond laser ) 是由 白振旭 陈晖� 齐瑶瑶 丁洁 杨学宗 王雨雷 吕志伟 于 2020-07-10 设计创作，主要内容包括：本发明公开了一种高功率高重复频率百皮秒激光器,包括：种子激光器发出第一频率种子光,经第一光隔离器进入一个双通放大器进行放大,依次通过第一反射镜、第一光束整形器、第一单通放大器、第二反射镜、第三反射镜、第二光束整形器以及第二光隔离器后,进入SBS脉冲压缩器将第一频率种子光压缩至第二频率激光；第二频率激光依次通过第四反射镜、第三光束整形器、若干第二单通放大器、第五反射镜、第六反射镜、第四光束整形器、若干四通板条放大器进行放大；放大后的激光通过第七反射镜、第五光束整形器、倍频器后产生第三频率激光,最后通过分光镜输出。本发明克服了固体SBS介质尺寸小、高功率激光对SBS材料的损伤和输出窄脉宽激光功率低等问题。(The invention discloses a high-power high-repetition-frequency hundred picosecond laser, which comprises: the seed laser emits first-frequency seed light, the first-frequency seed light enters a double-pass amplifier through a first optical isolator to be amplified, and the first-frequency seed light enters an SBS pulse compressor to be compressed to second-frequency laser after sequentially passing through a first reflector, a first beam shaper, a first single-pass amplifier, a second reflector, a third reflector, a second beam shaper and a second optical isolator; the second frequency laser is amplified through a fourth reflector, a third beam shaper, a plurality of second single-pass amplifiers, a fifth reflector, a sixth reflector, a fourth beam shaper and a plurality of four-way slab amplifiers in sequence; and the amplified laser passes through a seventh reflector, a fifth beam shaper and a frequency multiplier to generate third frequency laser, and is finally output through the spectroscope. The invention overcomes the problems of small size of solid SBS medium, damage of high power laser to SBS material, low power of output narrow pulse width laser, etc.)

1. A high power high repetition rate hundred picosecond laser, said laser comprising:

the seed laser emits first-frequency seed light, the first-frequency seed light passes through the first optical isolator, enters a double-pass amplifier for amplification, sequentially passes through the first reflector, the first beam shaper, the first single-pass amplifier, the second reflector, the third reflector, the second beam shaper and the second optical isolator, and enters the SBS pulse compressor to compress the first-frequency seed light to second-frequency laser;

the second frequency laser sequentially passes through a fourth reflector, a third beam shaper, a plurality of second single-pass amplifiers, a fifth reflector, a sixth reflector, a fourth beam shaper and a plurality of four-way slab amplifiers to be amplified;

and the amplified laser passes through a seventh reflector, a fifth beam shaper and a frequency multiplier to generate third frequency laser, and finally is output through the spectroscope.

2. The high-power high-repetition-frequency hundred picosecond laser device according to claim 1, wherein the first optical isolator and the second optical isolator are each composed of a first polarizer, a Faraday rotator and a first quarter wave plate, so that the incident seed light passes through the first polarizer in a single direction, and the backward transmitted light is deflected and emitted out when passing through the first polarizer due to the change of polarization state.

3. The high-power high-repetition-frequency hundred picosecond laser according to claim 1, wherein the double-pass amplifier is composed of a second polarizer, a first side pump module, a first quarter wave plate and a zero-degree total reflector;

the first quarter-wave plate is used for changing the polarization state of the seed light; the zero-degree total-reflection mirror is plated with a total-reflection film for the seed light of the first frequency, and forms an included angle of 90 degrees with the incident direction of the seed light of the first frequency, so that total reflection is realized.

4. The high power high repetition rate hundred picosecond laser of claim 1, wherein said first single pass amplifier is comprised of a second side pump module, a first 90 ° quartz rotor, and a third side pump module.

5. The high-power high-repetition-frequency hundred picosecond laser according to claim 1, wherein the SBS pulse compressor is composed of a third polarizer, a second quarter wave plate, a first focusing lens and a plurality of Brillouin media;

the second quarter-wave plate is used for changing the polarization state of the laser after pulse compression; the first focusing lens focuses the incident seed light into the Brillouin medium; the first frequency seed light is in a horizontal polarization state, is transmitted into the third polarizer, is changed into elliptical polarized light through the second quarter wave plate, is focused into a Brillouin medium through the first focusing lens to generate second frequency laser, is changed into a vertical polarization state through the first focusing lens and the second quarter wave plate after being subjected to backscattering and pulse compression, and is finally reflected out of the SBS pulse compressor through the third polarizer.

6. The high power high repetition rate hundred picosecond laser of claim 1, wherein said second single pass amplifier is comprised of a fourth side pump module, a second 90 ° quartz rotor, a second focusing lens, a first vacuum tube, a third focusing lens, a fifth side pump module, a second half wave plate, and a fourth polarizer, wherein a first aperture stop is disposed in the first vacuum tube;

the second focusing lens, the first vacuum tube, the first small-hole diaphragm and the third focusing lens jointly form a spatial filter for eliminating a spontaneous radiation amplification effect generated in an amplification process; the second half-wave plate and the fourth polarizer are combined to control the laser output energy without changing the polarization state of the laser.

7. The high power high repetition frequency hundred picosecond laser of claim 1, wherein said four-way slab amplifier is comprised of a fifth polarizer, a slab gain medium, an eighth mirror, a sixth beam shaper, a ninth mirror, a tenth mirror, a seventh beam shaper, a third quarter wave plate, an eleventh mirror, a fourth focusing lens, a second vacuum tube, a fifth focusing lens, a third half wave plate, wherein a second aperture stop is disposed within the second vacuum tube;

the sixth beam shaper and the seventh beam shaper are composed of a single optical lens or an optical lens group and are used for shaping the amplified seed beam to reduce the negative influence of the reduction of the amplification efficiency caused by beam divergence; the third quarter-wave plate is used for changing the polarization state of the laser in the amplification process; the eleventh reflector is plated with a total reflection film for the second frequency laser, and forms an included angle of 90 degrees with the incident direction of the second laser, so that the total reflection of the second frequency laser is realized.

Technical Field

The invention relates to the field of lasers, in particular to a high-power high-repetition-frequency hundred picosecond laser.

Background

As people go deep into space exploration, the activities of people entering space are increasing, but similar activities generate more and more space debris, which has great influence on satellite launching and space exploration, and the debris in space orbit needs to be detected. The conventional space target measurement is realized by radar, but the surface of the space debris has no angular reflector, the signal sent by the radar cannot be received and reflected, and the measurement by the radar is not feasible, so that the detection of the space debris by using laser becomes a great research hotspot in recent years.

The laser source used for space debris detection needs to be transmitted far enough, so that the laser source is required to have high energy, and to realize high-precision space measurement, the laser source is also required to have the characteristics of good beam quality, narrow pulse width and high repetition frequency, so that the acquisition of the laser source with narrow line width, high power and high repetition frequency is a key step for optimizing space detection.

The traditional space debris detection method adopts a nanosecond laser and combines a Main Oscillation Power Amplification (MOPA) method, but the pulse width of the traditional space debris detection method cannot meet the requirement of people on the distance measurement precision, so people are exploring the realization method of a high-energy picosecond laser.

At present, the technical means for obtaining picosecond pulse laser output mainly adopts a saturable absorber (SESAM) passive mode locking mode. However, the damage threshold of the saturable absorber is low, so that the output power of the passively mode-locked picosecond pulse laser is limited, and the passively mode-locked picosecond pulse laser is often amplified by combining a complex structure such as a regenerative amplifier, and the like, so that the cost is high, and the stability is difficult to control. Therefore, the large-energy nanosecond pulse compression is utilized to obtain large-energy output of hundreds of picoseconds and amplify the large-energy output, the difficult problem that the SESAM mode-locked laser is difficult to amplify efficiently can be effectively solved, the method is an important means for effectively obtaining a high-power picosecond laser source, the distance measurement precision is expected to be improved by 1-2 orders of magnitude, the cost of the laser is effectively controlled, and the stability is higher.

Disclosure of Invention

The invention provides a high-power high-repetition-frequency hundred picosecond laser, which overcomes the problems of small size of a solid SBS medium, damage of high-power laser to an SBS material, low power of output narrow-pulse-width laser and the like by combining a plurality of structures such as multi-stage amplification, series connection of a plurality of Stimulated Brillouin Scattering (SBS) solid media, compression and amplification, and the like, and is described in detail as follows:

a high power high repetition rate hundred picosecond laser, said laser comprising:

the seed laser emits first-frequency seed light, the first-frequency seed light passes through the first optical isolator, enters a double-pass amplifier for amplification, sequentially passes through the first reflector, the first beam shaper, the first single-pass amplifier, the second reflector, the third reflector, the second beam shaper and the second optical isolator, and enters the SBS pulse compressor to compress the first-frequency seed light to second-frequency laser;

the second frequency laser sequentially passes through a fourth reflector, a third beam shaper, a plurality of second single-pass amplifiers, a fifth reflector, a sixth reflector, a fourth beam shaper and a plurality of four-way slab amplifiers to be amplified;

and the amplified laser passes through a seventh reflector, a fifth beam shaper and a frequency multiplier to generate third frequency laser, and finally is output through the spectroscope.

The first optical isolator and the second optical isolator are composed of a first polarizer, a Faraday rotator and a first quarter wave plate, so that incident seed light passes through the first optical isolator in a single direction, and the reversely transmitted light is deflected and emitted out when passing through the first polarizer due to the change of the polarization state.

Furthermore, the double-pass amplifier consists of a second polarizer, a first side pump module, a first quarter wave plate and a zero-degree full mirror;

the first quarter-wave plate is used for changing the polarization state of the seed light; the zero-degree total-reflection mirror is plated with a total-reflection film for the seed light of the first frequency, and forms an included angle of 90 degrees with the incident direction of the seed light of the first frequency, so that total reflection is realized.

The first single-pass amplifier is composed of a second side pump module, a first 90-degree quartz rotor and a third side pump module.

Further, the SBS pulse compressor consists of a third polarizer, a second quarter-wave plate, a first focusing lens and a plurality of Brillouin media;

the second quarter-wave plate is used for changing the polarization state of the laser after pulse compression; the first focusing lens focuses the incident seed light into the Brillouin medium; the first frequency seed light is in a horizontal polarization state, is transmitted into the third polarizer, is changed into elliptical polarized light through the second quarter wave plate, is focused into a Brillouin medium through the first focusing lens to generate second frequency laser, is changed into a vertical polarization state through the first focusing lens and the second quarter wave plate after being subjected to backscattering and pulse compression, and is finally reflected out of the SBS pulse compressor through the third polarizer.

In specific implementation, the second single-pass amplifier is composed of a fourth side pump module, a second 90-degree quartz rotor, a second focusing lens, a first vacuum tube, a third focusing lens, a fifth side pump module, a second half wave plate and a fourth polarizer, wherein a first small-hole diaphragm is arranged in the first vacuum tube;

the second focusing lens, the first vacuum tube, the first small-hole diaphragm and the third focusing lens jointly form a spatial filter for eliminating a spontaneous radiation amplification effect generated in an amplification process; the second half-wave plate and the fourth polarizer are combined to control the laser output energy without changing the polarization state of the laser.

The four-way slab amplifier consists of a fifth polarizer, a slab gain medium, an eighth reflector, a sixth beam shaper, a ninth reflector, a tenth reflector, a seventh beam shaper, a third quarter wave plate, an eleventh reflector, a fourth focusing lens, a second vacuum tube, a fifth focusing lens and a third half wave plate, wherein a second aperture diaphragm is arranged in the second vacuum tube;

the sixth beam shaper and the seventh beam shaper are composed of a single optical lens or an optical lens group and are used for shaping the amplified seed beam to reduce the negative influence of the reduction of the amplification efficiency caused by beam divergence; the third quarter-wave plate is used for changing the polarization state of the laser in the amplification process; the eleventh reflector is plated with a total reflection film for the second frequency laser, and forms an included angle of 90 degrees with the incident direction of the second laser, so that the total reflection of the second frequency laser is realized.

The technical scheme provided by the invention has the beneficial effects that:

1. the laser adopts a mode of connecting a plurality of solid SBS media in series to increase the action distance of SBS pulse compression, can effectively carry out pulse compression on high repetition frequency laser, improves the pulse compression efficiency, and makes up the defect of small size of a single solid SBS medium;

2. the laser firstly performs pulse compression through SBS and then amplifies the laser power, so that the problem that the SBS material is damaged by high-power laser is solved;

3. the laser adopts a multistage amplification mode of a double-pass amplifier and a single-pass amplifier to amplify seed laser, and simultaneously adopts a mode of amplifying seed light after pulse compression by using a four-way slab amplifier, so that the effective amplification of hundred picosecond-order pulse laser can be realized, and the energy utilization rate and the amplification efficiency can be improved.

Drawings

FIG. 1 is a schematic diagram of a high power high repetition rate hundred picosecond laser;

FIG. 2 is a schematic diagram of a first optical isolator;

FIG. 3 is a schematic diagram of a two-pass amplifier;

FIG. 4 is a schematic diagram of a first one-way amplifier;

FIG. 5 is a schematic diagram of an SBS pulse compressor;

FIG. 6 is a schematic diagram of a second one-way amplifier;

FIG. 7 is a schematic diagram of a four-way slab amplifier;

fig. 8 is a schematic diagram of a structure of a series of multi-stage four-way slab amplifiers.

In the drawings, the components represented by the respective reference numerals are listed below:

1: a seed laser; 2: a first optical isolator;

3: a two-pass amplifier; 4: a first reflector;

5: a first beam shaper; 6: a first single pass amplifier;

7: a second reflector; 8: a third reflector;

9: a second beam shaper; 10: a second optical isolator;

11: an SBS pulse compressor; 12: a fourth mirror;

13: a third beam shaper; 14: a second single pass amplifier;

15: a fifth mirror; 16: a sixth mirror;

17: a fourth beam shaper; 18: a four-way slab amplifier;

19: a seventh mirror; 20: a fifth beam shaper;

21: a frequency multiplier; 22: a beam splitter.

Wherein

2-1: a first polarizer; 2-2: a Faraday rotator;

2-3: a first quarter wave plate;

3-1: a second polarizer; 3-2: a first side pump module;

3-3: a first quarter wave plate; 3-4: a zero degree total reflection mirror;

6-1: a second side pump module; 6-2: a first 90 ° quartz rotor;

6-3: a third side pump module;

11-1: a third polarizer; 11-2: a second quarter wave plate;

11-3: a first focusing lens; 11-4: a brillouin medium;

14-1: a fourth side pump module; 14-2: a second 90 ° quartz rotor;

14-3: a second focusing lens; 14-4: a first vacuum tube;

14-5: a first aperture diaphragm; 14-6: a third focusing lens;

14-7: a fifth side pump module; 14-8: a second half wave plate;

14-9: a fourth polarizer;

18-1: a fifth polarizer; 18-2: a slab gain medium;

18-3: an eighth mirror; 18-4: a sixth beam shaper;

18-5: a ninth mirror; 18-6: a tenth mirror;

18-7: a seventh beam shaper; 18-8: a third quarter wave plate;

18-9: an eleventh mirror; 18-10: a fourth focusing lens;

18-11: a second vacuum tube; 18-12: a second aperture diaphragm;

18-13: a fifth focusing lens; 18-14: a third half wave plate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below.

The defects existing in the traditional space target detection technology are known, and the laser can be used for quickly and accurately detecting the space target, particularly measuring space debris in a near-earth orbit, which has important significance for satellite emission and further space exploration. To realize long-distance space target detection by laser, the adopted laser source is required to have higher energy, and to realize high-precision space measurement, the laser source is also required to have the characteristics of good beam quality, narrow pulse width and high repetition frequency, so that the acquisition of the laser source with narrow line width, high power and high repetition frequency is a key step for optimizing space detection. The narrow linewidth laser output of picosecond magnitude can be obtained by adopting an SESAM passive mode locking mode, but the damage threshold of a saturable absorber is low, and the output power of pulse laser is greatly limited.

In summary, the present invention provides a high-power, narrow-linewidth, high repetition frequency laser source for space debris detection by using the injected seed light through the combination of multi-stage oscillation power amplification and SBS pulse compression.

In order to solve the problem that the traditional space target measurement technology is not suitable for space debris detection, the embodiment of the invention provides a high-power high-repetition-frequency hundred picosecond laser, and referring to fig. 1, the high-power high-repetition-frequency hundred picosecond laser comprises: the optical isolator comprises a seed laser 1, a first optical isolator 2, a double-pass amplifier 3, a first reflecting mirror 4, a first beam shaper 5, a first single-pass amplifier 6, a second reflecting mirror 7, a third reflecting mirror 8, a second beam shaper 9, a second optical isolator 10, an SBS pulse compressor 11, a fourth reflecting mirror 12, a third beam shaper 13, a second single-pass amplifier 14, a fifth reflecting mirror 15, a sixth reflecting mirror 16, a fourth beam shaper 17, a four-way slab amplifier 18, a seventh reflecting mirror 19, a fifth beam shaper 20, a frequency multiplier 21 and a beam splitter 22.

Wherein the seed laser 1 emits a first frequency (ω)_p) The single longitudinal mode kHz nanosecond seed light enters a double-pass amplifier 3 for amplification after passing through a first optical isolator 2, and then sequentially passes through a first reflector 4, a first beam shaper 5, a first single-pass amplifier 6 and a second reflectionAfter the mirror 7, the third mirror 8, the second beam shaper 9 and the second optical isolator 10 enter the SBS pulse compressor 11 to compress the nanosecond seed light of the first frequency to a second frequency (ω)_s) Laser, unit is hundred picoseconds;

the compressed laser is amplified through a fourth reflector 12, a third beam shaper 13, a plurality of second single-pass amplifiers 14, a fifth reflector 15, a sixth reflector 16, a fourth beam shaper 17 and a plurality of four-way slab amplifiers 18 in sequence;

the amplified laser beam passes through a seventh mirror 19, a fifth beam shaper 20 and a frequency multiplier 21 to generate a third frequency (omega)_H) Finally, the laser light is output through the beam splitter 22.

The first beam shaper 5, the second beam shaper 9, the third beam shaper 13, the fourth beam shaper 17 and the fifth beam shaper 20 are used for adjusting the divergence angle and the aperture of a light beam, and are composed of a single optical lens or an optical lens group.