CN114976839A - Solid laser - Google Patents
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- CN114976839A CN114976839A CN202210539182.4A CN202210539182A CN114976839A CN 114976839 A CN114976839 A CN 114976839A CN 202210539182 A CN202210539182 A CN 202210539182A CN 114976839 A CN114976839 A CN 114976839A
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- 239000007787 solid Substances 0.000 title claims abstract description 22
- 230000003321 amplification Effects 0.000 claims abstract description 38
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 38
- 238000005086 pumping Methods 0.000 claims abstract description 21
- 239000013078 crystal Substances 0.000 claims abstract description 13
- 230000003287 optical effect Effects 0.000 claims abstract description 12
- 230000010355 oscillation Effects 0.000 claims description 25
- 239000006096 absorbing agent Substances 0.000 claims description 24
- 230000005540 biological transmission Effects 0.000 claims description 20
- 238000002834 transmittance Methods 0.000 claims description 16
- 238000005530 etching Methods 0.000 claims description 13
- 238000009833 condensation Methods 0.000 claims description 2
- 230000005494 condensation Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 16
- 229910052724 xenon Inorganic materials 0.000 abstract description 5
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 abstract description 5
- 230000010287 polarization Effects 0.000 abstract description 3
- 230000000295 complement effect Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 7
- 241001270131 Agaricus moelleri Species 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 206010004950 Birth mark Diseases 0.000 description 1
- 206010014970 Ephelides Diseases 0.000 description 1
- 208000003351 Melanosis Diseases 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 208000017520 skin disease Diseases 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
- H01S3/2308—Amplifier arrangements, e.g. MOPA
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- H—ELECTRICITY
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0071—Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction
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- H—ELECTRICITY
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0085—Modulating the output, i.e. the laser beam is modulated outside the laser cavity
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
- H01S3/08059—Constructional details of the reflector, e.g. shape
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- H—ELECTRICITY
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
- H01S3/08072—Thermal lensing or thermally induced birefringence; Compensation thereof
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
- H01S3/092—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
- H01S3/1001—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by controlling the optical pumping
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/102—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
- H01S3/1022—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation by controlling the optical pumping
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
- H01S3/1061—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using a variable absorption device
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- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/1301—Stabilisation of laser output parameters, e.g. frequency or amplitude in optical amplifiers
Abstract
The invention discloses a solid laser, which comprises a local oscillator stage, an amplification stage and a reflector group; a 90-degree optical rotation crystal is arranged between the first light-gathering cavity and the second light-gathering cavity; the connecting direction of the first laser bar and the first pump lamp is vertical to the connecting direction of the second laser bar and the second pump lamp. The solid laser changes the radial and angular polarization directions of laser output by a first laser rod by arranging the 90-degree optically active crystal between a first light-gathering cavity and a second light-gathering cavity, the radial and angular phases of the laser are complementary after the laser passes through the second light-gathering cavity, the output laser has no phase delay and keeps vertical polarization, the problem of uneven pumping caused by pumping of xenon lamps is compensated by arranging the lamp rods in the first light-gathering cavity and the second light-gathering cavity, and the first pumping lamp and the second pumping lamp are connected in series, so that the pumping intensity of the two xenon lamps can be ensured to be the same, and the thermal birefringence effect can be compensated ideally.
Description
Technical Field
The invention relates to the technical field of laser, in particular to a high-electro-optical-efficiency solid laser with the functions of compensating thermotropic birefringence, compensating thermotropic distortion, modulating annular light spots without diffraction and distributing flat-top energy.
Background
In the laser field, electro-optical Q-switched lasers are often used for treating pigmented skin disorders such as freckles, tattoos, birthmarks, etc. due to their high peak power. At the present stage, the medical laser has high requirements on the quality of the light beam, and the effect on the treatment effect is large because the energy distribution of the light beam is uniform or not, so that the output energy distribution of the laser is required to be ideal flat-top distribution, and the high and low frequency output energy is consistent when the laser is injected into the tissue. The electro-optic Q-switched laser in the prior art cannot meet the clinical requirement index.
The electro-optical Q-switch for current medical treatment can only be pumped by a flash lamp, the single pulse output energy can be very large during the pumping of the flash lamp, but only 5% of the energy of the emission waveband of the electro-optical Q-switch can be converted into laser, and the rest energy can be converted into heat. The main side effects of heat in the output index of the laser are the thermal birefringence effect and the problem of uneven pumping. In the conventional electro-optical Q-switch, due to a thermal birefringence effect, when the electro-optical Q-switch works at high frequency, light spots of laser are in a cross shape, complementary parts of the cross shape are detected and deflected by a polarization sheet in a cavity and are reflected out of the cavity, so that great reflection loss is caused, and meanwhile, due to the fact that the light spots are in a cross shape, filling of gain substances of an amplification stage is reduced. The reflection loss of the oscillator stage and the gain material filling of the amplifier stage both decrease the overall photoelectric efficiency of the laser, and the higher the repetition frequency of the laser, the more severe the performance.
In the prior art, in a xenon lamp pumped Q-switched laser, the pulse width is short, the laser oscillation frequency is less, the light spot is generally elliptical, the light spot on one side is slightly heavy, and the energy distribution is uneven. According to the invention, two light-gathering cavities are adopted in the resonant cavity, and the connecting directions of the lamp rods of the two light-gathering cavities are mutually vertical, so that the light field excited by the laser when the laser oscillates in the resonant cavity is very uniform and shows that the light spot is an ideal circle. The round light spot is better filled in the amplification process of the amplification stage, the amplification factor is higher, and the electro-optic efficiency is obviously improved.
In the prior art, the energy distribution of laser output light spots is generally super-Gaussian, the Gaussian order is lower, the energy density in the middle of the light spots is high, and the energy density at the edges is low.
In view of the above technical problems, those skilled in the art are eagerly required to develop a solid laser with high electro-optical efficiency and uniform energy distribution that compensates for the thermal birefringence effect.
Disclosure of Invention
The invention aims to provide a solid laser which can compensate a thermal induced birefringence effect, simultaneously compensate the problem of small filling factor of an amplification level laser rod caused by nonuniform thermal induced pumping, improve the photoelectric conversion efficiency of the laser, and realize that the laser has different frequencies and the same final output energy when the laser has the same injection energy so as to meet the requirements of clinical treatment.
In order to achieve the above purpose, the invention provides the following technical scheme:
the invention relates to a solid laser, which is sequentially provided with the following components in the transmission direction of light beams:
a local oscillation stage;
an amplification stage; and
a mirror group located between the local oscillator stage and the amplification stage;
the local oscillator stage comprises a total reflection mirror, a quarter wave plate, a Pockels cell, a polarizing plate, a first light collecting cavity, a second light collecting cavity and an output mirror which are arranged along the light beam transmission direction;
a 90-degree optically active crystal is arranged between the first light-gathering cavity and the second light-gathering cavity;
a first laser bar and a first pump lamp are arranged in the first light-gathering cavity;
a second laser bar and a second pumping lamp are arranged in the second light-focusing cavity;
the connecting direction of the first laser bar and the first pump lamp is vertical to the connecting direction of the second laser bar and the second pump lamp;
the local oscillation stage outputs vertical polarized light along the transmission direction of the light beam through the first light gathering cavity and the second light gathering cavity, and the vertical polarized light is transmitted to the amplification stage through the reflector group.
Further, the local oscillation stage is configured to:
the laser in the first light-gathering cavity and the laser in the second light-gathering cavity form oscillation, and the oscillation sequentially passes through the polaroid, the Pockels cell, the quarter-wave plate and the total reflector to form linearly polarized light;
the linearly polarized light is transmitted to the first light-gathering cavity through the quarter-wave plate, the Pockels cell and the polarizing plate in sequence and passes through the first laser rod of the first light-gathering cavity to form horizontal polarized light;
the horizontally polarized light is transmitted to the second light condensing cavity through the 90-degree optically active crystal, and the horizontally polarized light is formed into the vertically polarized light through a second laser rod of the second light condensing cavity.
Further, a first pump lamp of the first light-gathering cavity is connected in series with a second pump lamp of the second light-gathering cavity;
the first pump lamp and the first laser rod are positioned on the same horizontal plane or the same vertical plane and are arranged in parallel;
the second laser bar and the second pump lamp are positioned on the same vertical plane or the same horizontal plane and are arranged in parallel.
Further, the total reflection mirror is a binary diffraction total reflection mirror;
the surface of the total reflector is etched by binary light to form a plurality of uniformly distributed regular hexagon etching patterns, and the surface of the etching patterns of the total reflector is plated with a high-reflection film of oscillation laser.
Further, an output mirror is arranged at the light beam output end of the second light condensing cavity;
the reflector group comprises a first reflector and a second reflector;
and the vertical polarized light output by the second light-focusing cavity passes through the output mirror, the first reflecting mirror and the second reflecting mirror in sequence and is transmitted to the third light-focusing cavity.
Further, a saturable absorber is arranged at any position of an optical path between the output mirror and the third light focusing cavity;
the saturable absorber is Cr: YAG;
the saturable absorber has an initial transmittance ranging from 20% to 90%.
Further, a cylindrical lens is arranged at any position of an optical path between the output mirror and the third light condensing cavity.
Further, the cylindrical lens is a cylindrical lens with a transmission area with ultrahigh Gaussian transmittance;
the outer diameter of a transmission area of the cylindrical lens is smaller than the size of the laser rod in the third light condensation cavity, and the focal length range of the cylindrical lens is 2-15 m.
Furthermore, the size of the outer diameter of the transmission area of the cylindrical lens is 0.5 mm-1 mm smaller than the diameter of the laser rod in the third cavity.
In the above technical solution, the solid laser with compensation for the thermal birefringence effect provided by the present invention has the following beneficial effects:
1. adopt the spotlight chamber that two lamp sticks mutually perpendicular placed in the local oscillator level: the laser facula that can make the output is circular, has solved among the prior art the uneven and laser facula that leads to of pumping in single chamber for oval and facula one side energy density high problem. After the light spots are rounded, in the amplification process, the filling of the laser rod in the third light focusing cavity is improved to a certain extent, and further the photoelectric efficiency is improved.
2. Adding 90-degree optical crystal between two cavities of the local oscillation stage: the problem that the light spot is changed from a circular shape to a cross shape in high-frequency operation caused by thermal birefringence can be ideally compensated. The filling of the third laser rod is reduced to a certain extent in the amplification process of the cross-shaped light spot, so that the output single pulse energy of high-frequency work is reduced. By adding 90-degree optical rotation crystals between the double cavities, the consistency of the light spot energy distribution and the single pulse energy is ensured when the repetition frequency changes.
3. A saturable absorber is added between the output mirror of the local oscillator stage and the third light cavity: before the Q switch is opened, if the pumping intensity is higher, the fluorescence intensity of the laser rod is also very high, the fluorescence of the amplification level can reach the local oscillator level laser rod through the output mirror, so that the spontaneous emission Amplification (ASE) phenomenon can be generated, the energy storage of all laser rods is influenced, and the electro-optic efficiency of the laser is reduced. By adding a saturable absorber having a suitable initial transmittance, the generation of ASE between stages can be prevented, and the electro-optical efficiency can be improved. Meanwhile, after the local oscillator stage emits laser, the saturable absorber can absorb weak light at the front edge of the pulse, and the amplified laser pulse width can be reduced to a certain extent.
4. A cylindrical lens with Gaussian transmittance is added between the local oscillation stage output mirror and the third light condensing cavity: the Gaussian transmittance can reduce that laser spots are concentric circular rings caused by annular diffraction modulation generated due to the aperture limitation of the third laser rod; meanwhile, the cylindrical mirror with proper focal length can compensate the problem of out-of-round far-field laser caused by uneven heat pump of the third light focusing cavity.
5. Binary diffraction total reflection mirror: by changing the traditional common spherical total reflection mirror into the total reflection mirror after binary optical etching, the diffraction effect in the reflection oscillation process can make the fluorescence in the cavity more uniform, so that the energy distribution of the output laser in a far field is in a flat-top hat shape.
6. The cylindrical lens with the Gaussian transmittance can reduce the annular diffraction modulation light spots generated due to the limitation of the aperture of the amplification rod, and meanwhile, the cylindrical lens can compensate the elliptical pumping gain of the amplification level; the saturable absorber can prevent the interstage pump withdrawal, improve the voltage for closing the door and reduce the laser output pulse width at the same time; the binary diffraction total reflection mirror replaces a common total reflection mirror, so that the uniformity of light spots can be homogenized to a certain degree, and the far-field light spots are in flat-top energy distribution.
Drawings
In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings required in the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to these drawings.
Fig. 1 is a schematic structural diagram of a solid-state laser according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an internal pattern of a total reflection mirror of a solid-state laser according to an embodiment of the present invention;
fig. 3 is a layout diagram of lamp rods in the first light-condensing cavity and the second light-condensing cavity of the solid-state laser according to the embodiment of the present invention.
Description of reference numerals:
1. a total reflection mirror; 2. a quarter wave plate; 3. pockels cell; 4. a polarizing plate; 5. a first light collection cavity; 6. 90-degree optically active crystals; 7. a second light condensing cavity; 8. an output mirror; 9. a first reflector; 10. a saturable absorber; 11. a second reflector; 12. a cylindrical lens; 13. and a third light condensing cavity.
101. Etching a pattern in a regular hexagon;
501. a first pump lamp; 502. a first laser bar;
701. a second pump lamp; 702. a second laser bar.
Detailed Description
In order to make the technical solutions of the present invention better understood, those skilled in the art will now describe the present invention in further detail with reference to the accompanying drawings.
See fig. 1-3;
the invention relates to a solid laser, which is sequentially provided with the following components in the transmission direction of light beams:
a local oscillation stage;
an amplification stage; and
a mirror group located between the local oscillator stage and the amplification stage;
the local oscillation stage comprises a total reflection mirror 1, a quarter wave plate 2, a Pockels cell 3, a polarizing plate 4, a first light collecting cavity 5, a second light collecting cavity 7 and an output mirror 8 which are arranged along the light beam transmission direction;
a 90-degree optically active crystal 6 is arranged between the first light-gathering cavity 5 and the second light-gathering cavity 7;
a first laser bar 502 and a first pump lamp 501 are arranged in the first light-gathering cavity 5;
a second laser bar 702 and a second pump lamp 701 are arranged in the second light condensing cavity 7;
the connection direction of the first laser bar 502 and the first pumping lamp 501 is vertical to the connection direction of the second laser bar 702 and the second pumping lamp 701;
the local oscillator stage outputs vertically polarized light in the transmission direction of the light beam through the first condensing chamber 5 and the second condensing chamber 7, and the vertically polarized light is transmitted to the amplification stage through the mirror group.
The embodiment discloses a solid laser capable of compensating for a thermal birefringence effect, which mainly includes a local oscillator stage, a mirror group and an amplification stage, and in order to compensate for the thermal birefringence effect, two sets of light-collecting cavities, namely the first light-collecting cavity 5 and the second light-collecting cavity 7, are arranged at the local oscillator stage.
Among them, more specifically:
the local oscillator stage is configured to:
the laser in the first light-gathering cavity 5 and the second light-gathering cavity 7 forms oscillation and is reflected by the polaroid 4, the Pockels cell 3, the quarter-wave plate 2 and the total reflection mirror 1 in sequence to form linearly polarized light;
linearly polarized light is transmitted to the first light collecting cavity 5 through the quarter-wave plate 2, the Pockels cell 3 and the polarizer 4 in sequence and is formed into horizontally polarized light through the first laser rod 502 of the first light collecting cavity 5;
the horizontally polarized light is transmitted to the second light condensing cavity 7 through the 90-degree optically active crystal 6, and the horizontally polarized light is formed into vertically polarized light after passing through the second laser rod 702 and the output mirror 8 of the second light condensing cavity 7.
Preferably, in this embodiment, the first pump lamp 501 of the first light-gathering cavity 5 is connected in series with the second pump lamp 701 of the second light-gathering cavity 7;
the first pump lamp 501 and the first laser rod 502 are positioned on the same horizontal plane or the same vertical plane and arranged in parallel;
the second laser bar 702 and the second pump lamp 701 are arranged in parallel on the same vertical plane or the same horizontal plane.
First, the arrangement of the lamp rods in the first light-gathering cavity 5 and the second light-gathering cavity 7 will be further explained and explained, wherein a first pump lamp 501 and a first laser rod 502 are arranged in the first light-gathering cavity 5, a second pump lamp 701 and a second laser rod 702 are arranged in the second light-gathering cavity 7, as shown in fig. 3, the first pump lamp 501 and the second pump lamp 701 are coaxially arranged in series, the first laser rod 502 in the first light-gathering cavity 5 and the first pump lamp 501 are arranged in parallel on the same horizontal plane or the same vertical plane, and the second laser rod 702 and the second pump lamp 701 are arranged in parallel on the same vertical plane or the same horizontal plane in the second light-gathering cavity 7, so that the connection direction of the lamp rods in the first light-gathering cavity 5 is perpendicular to the connection direction of the lamp rods in the second light-gathering cavity 7, which can compensate the problem of uneven pumping caused by xenon lamp pumping. And the two pump lamps are connected in series, so that the pump intensity of the two xenon lamps can be ensured to be the same, and the thermal induced birefringence effect can be ideally compensated.
Preferably, the total reflection mirror 1 in this embodiment is a binary diffractive total reflection mirror;
the surface of the total reflector 1 is etched by binary light to form a plurality of uniformly distributed regular hexagonal etching patterns 101, and the surface of the etching patterns of the total reflector 1 is plated with a high-reflection film of oscillation laser.
The total reflector 1 of this embodiment is a binary diffractive total reflector, which performs binary optical etching on a reflective substrate to form a plurality of tightly arranged raised regular hexagonal etching patterns 101, wherein a certain etching depth is provided between narrow bands, and a high reflective film of oscillation laser is plated on the surface of the etching patterns to homogenize the oscillation beam in the resonant cavity.
The output end of the light beam of the second condenser cavity 7 of the present embodiment is provided with an output mirror 8;
the reflector group comprises a first reflector 9 and a second reflector 11;
the horizontally polarized light output by the second light focusing cavity 7 passes through the output mirror 8, the first reflecting mirror 9 and the second reflecting mirror 11 in sequence and is transmitted to the third light focusing cavity 13.
Wherein, a saturable absorber 10 is arranged at any position of the optical path between the output mirror 8 and the third light focusing cavity 13;
the saturable absorber 10 is Cr: YAG, the saturable absorber 10 can prevent the interstage pump withdrawal, improve the voltage of closing the door, reduce the laser output pulse width at the same time, improve the photoelectric efficiency of the laser and laser peak power;
the saturable absorber 10 has an initial transmittance T ranging from 20% to 90%.
The reflecting mirror group of this embodiment includes a first reflecting mirror 9 and a second reflecting mirror 11, and the horizontal polarized light output by the local oscillation stage is reflected by the first reflecting mirror 9 and the second reflecting mirror 11 in sequence after passing through the output mirror 8 and then transmitted to the third light condensing cavity 13 of the amplification stage. The saturable absorber 10 is interposed between the first mirror 9 and the second mirror 11 of the present embodiment, so that spontaneous emission Amplification (ASE) between the local oscillation stage and the amplification stage can be prevented from being excited with each other. When the local oscillator stage has partial laser output and the laser does not reach the saturation value of the saturable absorber 10, the saturable absorber 10 plays a role in isolating mutual excitation between the local oscillator stage and the amplification stage; when the output intensity of the local oscillator level laser reaches the saturation value of the saturable absorber 110, the saturable absorber 10 allows the laser from the local oscillator level to enter the third light condensing cavity 13 in the amplification stage finally after being reflected by the mirror group.
Preferably, a cylindrical lens 12 is disposed between the second reflector 11 and the third light-focusing cavity 13 in this embodiment.
Among them, more specifically:
the cylindrical lens 12 is a cylindrical lens 12 having a transmission region with super-gaussian transmittance;
the outer diameter of the transmission area of the cylindrical lens 12 is smaller than the size of the laser rod in the third light condensing cavity 13, and the focal length range of the cylindrical lens 12 is 2 m-15 m.
Preferably, the outer diameter of the transmission region of the cylindrical lens 12 of the present embodiment is smaller than the diameter of the third intracavity laser rod by 0.5mm to 1 mm.
Before the local oscillator level laser enters the amplification level, a cylindrical lens 12 with super-Gaussian transmittance is arranged between the second reflecting mirror 11 and the third light condensing cavity 13, and the outer diameter of the transmission area of the super-Gaussian transmittance mirror of the cylindrical lens 12 is slightly smaller than the diameter of a laser rod of the amplification level, so that the diffraction effect of the laser rod of the amplification level can be effectively avoided, the formation of a far-field light spot diffraction ring is avoided, and the thermal lens space distortion of the gain material of the amplification level is compensated. Specific preferred size ranges are detailed above.
Because the heat effect of the single lamp pump is represented by an ellipse-like thermal lens, namely the focal length of the thermal lens of the gain medium of the amplifier stage in the direction of the lamp rod connecting line is smaller than that of the thermal lens perpendicular to the direction of the lamp rod connecting line, the cylindrical lens 12 can compensate the difference of the focal lengths in the two directions to a great extent, so that the far-field light spot is in a better circular shape. Because the focus of cylindrical lens 12 is generally great, mostly 3m ~ 8m, has almost not influence to near field light, does not influence the laser rod and packs, and the inside circular pattern that is laser beam machining of cylindrical lens has super Gaussian distribution at the transmittance of radius direction, and the Gaussian external diameter slightly is less than the diameter of amplification level work material, can prevent like this to lead to far field facula to appear ring type modulation pattern because of the diffraction.
In the technical scheme, the solid laser provided by the invention has the following beneficial effects:
1. adopt the spotlight chamber that two lamp sticks mutually perpendicular placed in the local oscillator level: the laser facula that can make the output is circular, has solved among the prior art the uneven and laser facula that leads to of pumping in single chamber for oval and facula one side energy density high problem. After the light spots are rounded, in the amplification process, the filling of the laser rod in the third light focusing cavity 13 is improved to a certain extent, and further the photoelectric efficiency is improved.
2. Adding a 90-degree optical crystal 6 between two cavities of the local oscillation stage: the problem that the light spot is changed from a circular shape to a cross shape in high-frequency operation caused by thermal birefringence can be ideally compensated. The filling of the third laser rod is reduced to a certain extent in the amplification process of the cross-shaped light spot, so that the output single pulse energy of high-frequency work is reduced. By adding the 90-degree optically active crystal 6 between the double cavities, the consistency of the light spot energy distribution and the single pulse energy is ensured when the repetition frequency is changed.
3. A saturable absorber 10 is added between the output mirror 8 of the local oscillation stage and the third light-focusing cavity 13: before the Q switch is opened, if the pumping intensity is higher, the fluorescence intensity of the laser rod is also very high, the fluorescence of the amplification level can reach the local oscillator level laser rod through the output mirror, so that the spontaneous emission Amplification (ASE) phenomenon can be generated, the energy storage of all laser rods is influenced, and the electro-optic efficiency of the laser is reduced. By adding a saturable absorber having a suitable initial transmittance, the generation of ASE between stages can be prevented, and the electro-optical efficiency can be improved. Meanwhile, after the local oscillator stage emits laser, the saturable absorber 10 can absorb weak light at the front edge of the pulse, and the amplified laser pulse width can be reduced to a certain extent.
4. A cylindrical lens 12 with Gaussian transmittance is added between the local oscillator output mirror 8 and the third light condensing cavity 13: the Gaussian transmittance can reduce that laser spots are concentric circular rings caused by annular diffraction modulation generated due to the aperture limitation of the third laser rod; meanwhile, the cylindrical lens 12 with a proper focal length can compensate the problem of out-of-round far-field laser caused by uneven heat pump of the third light focusing cavity 13.
5. Binary diffractive total reflection mirror: by changing the traditional common spherical total reflection mirror into the total reflection mirror 1 after binary optical etching, the diffraction effect in the reflection oscillation process can make the fluorescence in the cavity more uniform, so that the energy distribution of the output laser in a far field is in a flat-top hat shape.
6. The cylindrical lens 12 with the Gaussian transmittance can reduce the annular diffraction modulation light spots generated due to the limitation of the aperture of the amplification rod, and meanwhile, the cylindrical lens 12 can compensate the elliptical pumping gain of the amplification level; the saturable absorber 10 can prevent the pumping from being withdrawn between stages, improve the voltage for closing the door and reduce the output pulse width of the laser at the same time; the binary diffraction total reflection mirror replaces a common total reflection mirror, so that the uniformity of light spots can be homogenized to a certain degree, and the far-field light spots are in flat-top energy distribution.
While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the invention.
Claims (9)
1. Solid state laser, characterized in that, this solid state laser arranges in proper order according to the transmission direction of light beam:
a local oscillation stage;
an amplification stage; and
a mirror group located between the local oscillator stage and the amplification stage;
the local oscillator stage comprises a total reflection mirror (1), a quarter wave plate (2), a Pockels cell (3), a polarizing plate (4), a first light-collecting cavity (5), a second light-collecting cavity (7) and an output mirror (8), wherein the total reflection mirror (1), the quarter wave plate (2), the Pockels cell, the polarizing plate (4) and the first light-collecting cavity are arranged along the light beam transmission direction;
a 90-degree optically active crystal (6) is arranged between the first light-gathering cavity (5) and the second light-gathering cavity (7);
a first laser bar (502) and a first pump lamp (501) are arranged in the first light-gathering cavity (5);
a second laser bar (702) and a second pumping lamp (701) are arranged in the second light-focusing cavity (7);
the connecting direction of the first laser bar (502) and the first pump lamp (501) is vertical to the connecting direction of the second laser bar (702) and the second pump lamp (701);
the local oscillation stage outputs vertical polarized light along the transmission direction of light beams through the first light gathering cavity (5) and the second light gathering cavity (7), and the vertical polarized light is transmitted to the amplification stage through the reflector group.
2. The solid state laser of claim 1, wherein the local oscillator stage is configured to:
the laser in the first light-gathering cavity (5) and the second light-gathering cavity (7) forms oscillation and is reflected by the polaroid (4), the Pockels cell (3), the quarter-wave plate (2) and the total reflection mirror (1) in sequence to form linearly polarized light;
the linearly polarized light is transmitted to the first light-gathering cavity (5) through the quarter-wave plate (2), the Pockels cell (3) and the polarizing plate (4) in sequence and forms horizontal polarized light through a first laser rod (502) of the first light-gathering cavity (5);
the horizontally polarized light is transmitted to the second light condensing cavity (7) through the 90-degree optically active crystal (6), and the horizontally polarized light is formed into the vertically polarized light through a second laser rod (702) of the second light condensing cavity (7).
3. Solid state laser according to claim 1, characterized in that the first pump lamp (501) of the first concentrating cavity (5) is connected in series with the second pump lamp (701) of the second concentrating cavity (7);
the first pump lamp (501) and the first laser rod (502) are positioned on the same horizontal plane or the same vertical plane and are arranged in parallel;
the second laser bar (702) and the second pump lamp (701) are positioned on the same vertical plane or the same horizontal plane and are arranged in parallel.
4. Solid state laser according to claim 1, characterized in that the total reflection mirror (1) is a binary diffractive total reflection mirror;
the surface of the total reflector (1) is etched by binary light to form a plurality of uniformly distributed regular hexagonal etching patterns (101), and the surface of the etching patterns of the total reflector (1) is plated with a high-reflection film of oscillation laser.
5. Solid state laser according to claim 1, characterized in that the beam output end of the second cavity (7) is arranged with an output mirror (8);
the reflector group comprises a first reflector (9) and a second reflector (11);
the vertically polarized light output by the second light-focusing cavity (7) passes through the output mirror (8), the first reflecting mirror (9) and the second reflecting mirror (11) in sequence and is transmitted to the third light-focusing cavity (13).
6. Solid state laser according to claim 5, characterized in that a saturable absorber (10) is arranged at any position of the optical path between the output mirror (8) and the third cavity (13);
the saturable absorber (10) is Cr: YAG;
the saturable absorber (10) has an initial transmittance ranging from 20% to 90%.
7. Solid state laser according to claim 5, characterized in that a cylindrical lens (12) is arranged at any position of the optical path between the output mirror (8) and the third cavity (13).
8. Solid state laser according to claim 7, characterized in that the cylindrical lens (12) is a cylindrical lens (12) having a transmission region with a transmission rate of super-Gaussian;
the outer diameter of a transmission area of the cylindrical lens (12) is smaller than the size of a laser rod in the third light condensation cavity (13), and the focal length range of the cylindrical lens (12) is 2-15 m.
9. The solid state laser according to claim 8, wherein the outer diameter of the transmission area of the cylindrical lens (12) is smaller than the diameter of the third intracavity laser rod by 0.5mm to 1 mm.
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| CN1421967A (en) * | 2001-11-23 | 2003-06-04 | 中国科学院福建物质结构研究所 | Double lamp pumped great-power solid laser with serially connected rods |
| CN1763572A (en) * | 2005-09-20 | 2006-04-26 | 江苏大学 | Saturable absorber optical isolator |
| CN1972034A (en) * | 2006-09-19 | 2007-05-30 | 天津大学 | Low energy consumption high power two rods concatenation plano-concave green light laser |
| CN101399424A (en) * | 2008-10-10 | 2009-04-01 | 江苏大学 | Novel high-power strip laser system |
| CN101604816A (en) * | 2009-07-03 | 2009-12-16 | 江苏大学 | A kind of method and apparatus that improves macro-energy neodymium glass laser repetition rate and stability |
| CN204287551U (en) * | 2014-12-26 | 2015-04-22 | 北京镭宝光电技术有限公司 | The laser of a kind of macro-energy, narrow spaces and the coupling device of optical fiber |
| CN207705562U (en) * | 2017-12-29 | 2018-08-07 | 北京卓镭激光技术有限公司 | A kind of laser system of homogenizer |
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2021
- 2021-05-20 CN CN202110550200.4A patent/CN113300201A/en active Pending
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- 2022-05-18 CN CN202210539182.4A patent/CN114976839A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421967A (en) * | 2001-11-23 | 2003-06-04 | 中国科学院福建物质结构研究所 | Double lamp pumped great-power solid laser with serially connected rods |
| CN1763572A (en) * | 2005-09-20 | 2006-04-26 | 江苏大学 | Saturable absorber optical isolator |
| CN1972034A (en) * | 2006-09-19 | 2007-05-30 | 天津大学 | Low energy consumption high power two rods concatenation plano-concave green light laser |
| CN101399424A (en) * | 2008-10-10 | 2009-04-01 | 江苏大学 | Novel high-power strip laser system |
| CN101604816A (en) * | 2009-07-03 | 2009-12-16 | 江苏大学 | A kind of method and apparatus that improves macro-energy neodymium glass laser repetition rate and stability |
| CN204287551U (en) * | 2014-12-26 | 2015-04-22 | 北京镭宝光电技术有限公司 | The laser of a kind of macro-energy, narrow spaces and the coupling device of optical fiber |
| CN207705562U (en) * | 2017-12-29 | 2018-08-07 | 北京卓镭激光技术有限公司 | A kind of laser system of homogenizer |
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