CN114883896A - 2 mu m laser - Google Patents
2 mu m laser Download PDFInfo
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- CN114883896A CN114883896A CN202210338651.6A CN202210338651A CN114883896A CN 114883896 A CN114883896 A CN 114883896A CN 202210338651 A CN202210338651 A CN 202210338651A CN 114883896 A CN114883896 A CN 114883896A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01S3/08013—Resonator comprising a fibre, e.g. for modifying dispersion or repetition rate
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094042—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a fibre laser
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094049—Guiding of the pump light
- H01S3/094053—Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
Abstract
The invention provides a 2 μm laser, comprising: the device comprises a main oscillation component and an amplification component, wherein the main oscillation component adopts a Tm fiber laser pumping group to perform end-face pumping on a main oscillation Ho slab crystal to generate 2 mu m seed light; the amplifying component adopts an angle multiplexing mode, so that 2 mu m seed light passes through the amplifying level Ho slab crystal for multiple times, and 2 mu m laser is extracted under the condition of pumping of the amplifying level Tm fiber laser pumping set, so that multi-pass amplification is realized and output is realized. The invention adopts the Tm fiber laser to replace a solid laser pump source, carries out end face pumping on the main oscillation Ho slab crystal, adopts an angle multiplexing mode at an amplifying component, extracts 2 mu m laser under the pumping condition of an amplifying Tm fiber laser pumping set, realizes multi-pass amplification and then outputs the laser, thereby greatly improving the amplification efficiency while reducing the volume of the laser, realizing large-area heat dissipation by adopting the slab crystal and improving the output stability and the beam quality of the 2 mu m laser.
Description
Technical Field
The invention relates to the technical field of laser, in particular to a 2-micrometer laser.
Background
The 2 mu m wave band laser plays an important role in the medical field and the infrared countermeasure field. At present, a 2 μm Laser is obtained by mainly using a Laser diode (Laser diode) to pump a Tm and Ho ion doped rod-shaped Laser crystal, and simultaneously, a main oscillator amplifier (MOPA) structure is used to realize high power output, and the power of the output Laser is mostly in the order of tens of watts to hundreds of watts.
On one hand, because of the adoption of the rod-shaped crystal, the central temperature of the crystal is higher, and the temperature gradient with the periphery is large, so that a serious heat effect can be caused, the further improvement of the laser output index is greatly influenced, and the quality of the output laser beam is poor. On the other hand, the rod-shaped crystal can not realize high-efficiency multi-pass amplification output and high-power 2 mu m output, and has the defect of large laser volume.
Disclosure of Invention
The invention aims to solve the technical problem of improving the output power, efficiency and beam quality of 2-micron-band laser, and provides a 2-micron laser.
A 2 μm laser according to an embodiment of the present invention includes:
the main oscillation component adopts a Tm fiber laser pumping group to carry out end-face pumping on a main oscillation Ho slab crystal to generate 2 mu m seed light;
and the amplification component adopts an angle multiplexing mode, so that the 2 mu m seed light passes through the amplification level Ho slab crystal for multiple times, and extracts 2 mu m laser under the condition of pumping of the amplification level Tm fiber laser pumping set, thereby realizing multi-pass amplification and output.
According to the 2-micron laser, a Tm fiber laser with the beam quality close to the diffraction limit is adopted to replace a solid laser pump source, end face pumping is carried out on a main oscillation Ho slab crystal, 2-micron laser is extracted under the condition of a pumping set of an amplification grade Tm fiber laser in an angle multiplexing mode on an amplification component, and output after multi-pass amplification is achieved, so that the amplification efficiency is greatly improved while the size of the laser is reduced, large-area heat dissipation can be achieved by adopting the slab crystal, the thermal effect is reduced, and the output stability and the beam quality of the 2-micron laser are improved.
According to some embodiments of the invention, the master oscillating assembly comprises: tm fiber laser pump group, pump optical coupling mirror, Ho laser resonator, the Ho laser resonator includes: the device comprises a first full-reflection mirror assembly, a 45-degree reflection mirror, a main oscillation Ho slab crystal, an etalon, a Q-switching device and an output mirror system;
the Tm fiber laser pumping group performs end face pumping on the main oscillation Ho slab crystal, the main oscillation Ho slab crystal generates stimulated fluorescence radiation after absorbing pump light energy, and 2 mu m seed light is output after being amplified under the action of the Ho laser resonant cavity.
In some embodiments of the invention, the amplifying assembly comprises: the device comprises a second full-reflection mirror assembly, a third full-reflection mirror assembly, an amplification stage coupling mirror, a beam transformation module, a polaroid, a 45-degree mirror, an amplification stage Ho slab crystal, an amplification stage Tm fiber laser pumping set, a reflector, an 1/4 wave plate and a lens;
and the amplification level Tm fiber laser pumping group performs end face pumping on the amplification level Ho slab crystal, and outputs the 2 mu m seed light from a polaroid after multi-pass amplification.
According to some embodiments of the invention, the Tm fiber laser pumping set comprises: and the pumping lasers of the first Tm fiber laser and the second Tm fiber laser are respectively coupled into the main oscillation Ho slab crystal from two ends of the main oscillation Ho slab crystal to carry out end face pumping.
In some embodiments of the present invention, the amplification stage Tm fiber laser pumping set comprises: and the pumping lasers of the third Tm fiber laser and the fourth Tm fiber laser are respectively coupled into the amplification stage Ho slab crystal from two ends of the amplification stage Ho slab crystal to carry out end face pumping.
According to some embodiments of the invention, the master oscillating Ho slab crystal and the amplification stage Ho slab crystal are Ho: YAG lath laser crystal with doping concentration of 0.5%.
In some embodiments of the present invention, the master oscillating Ho slab crystal and the amplification stage Ho slab crystal are Ho: the doping concentration of the YLF slab laser crystal is 1 percent.
According to some embodiments of the present invention, the end faces of the main oscillation Ho slab crystal and the amplification-stage Ho slab crystal are both coated with antireflection film layers, and the transmittance of the antireflection film layers to laser light in a wavelength band range of 1.9 μm to 2.1 μm is: t is 1.9-2.1 ＞99.9％。
In some embodiments of the present invention, the main oscillation Ho slab crystal and the amplification stage Ho slab crystal both employ heat sinks for heat dissipation.
According to some embodiments of the invention, the laser light in the amplification stage Ho slab crystal propagates in a zigzag shape.
Drawings
FIG. 1 is a schematic diagram of a conventional 2 μm laser;
FIG. 2 is a schematic diagram of a 2 μm laser composition according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a 2 μm laser according to another embodiment of the present invention;
FIG. 4 is a schematic illustration of laser light transmission inside a slab in a 2 μm laser according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a rod-shaped crystal and a plate-shaped crystal package according to an embodiment of the invention.
Reference numerals:
the laser(s) 100 are (are),
the main oscillating assembly (10) is,
a first Tm fiber laser 11, a second Tm fiber laser 12,
a first coupling mirror 101, a second coupling mirror 102,
a first total reflection mirror assembly 13, a 45-degree reflection mirror 14, a main oscillation Ho slab crystal 15, an etalon 16, a Q-switching device 17, an output mirror system 18,
the amplification member 20 is provided with a plurality of amplification elements,
a third Tm fiber laser 21, a fourth Tm fiber laser 22,
a second all-reflective mirror assembly 201, a beam-shifting module 202, a polarizer 203, a third all-reflective mirror assembly 204,
a first 45 ° mirror 211, a second 45 ° mirror 212, a first lens 221, a second lens 222, a third lens 223, a first mirror 231, a second mirror 232, a third coupling mirror 241, a fourth coupling mirror 242, a wave plate 23, and a magnification-stage Ho slab crystal 24.
Detailed Description
To further explain the technical means and effects of the present invention adopted to achieve the intended purpose, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.
The description of the method flow in the present specification and the steps of the flow chart in the drawings of the present specification are not necessarily strictly performed by the step numbers, and the execution order of the method steps may be changed. Moreover, certain steps may be omitted, multiple steps may be combined into one step execution, and/or a step may be broken down into multiple step executions.
At present, two main technical means for realizing the output of 2 μm wave band laser with higher power are available, one is to generate 2.12 μm wavelength laser output by carrying out nonlinear conversion on 1.06 μm wavelength laser, and the method has the advantages of low threshold value, small technical difficulty and low efficiency and is difficult to obtain high power output; the other mode is that Tm and Ho ion doped laser crystal material is adopted to directly generate 2 mu m wave band laser output by semiconductor laser pumping, and the laser crystal material has the advantages of high efficiency, small volume, light weight, simple power supply, compact structure and the like, thereby becoming a main technical means for realizing high-power 2 mu m laser output.
In the prior art, in order to realize high-power 2 μm laser output and ensure the stability and beam quality of output laser, a main oscillation amplifier (MOPA) structure is usually adopted, and a multistage amplifier structure is added at the rear end of a dozen-watt main oscillation seed light to realize 2 μm output of 200W magnitude. Fig. 1 shows a schematic diagram of two-stage amplification of a Tm laser (solid state) pumped Ho crystal MOPA in the prior art.
The pump source of the Ho crystal in the existing structure is mostly a continuous Tm solid laser, during high-power output, the beam quality is relatively poor, the condition of multimode output can appear usually, the Ho crystal adopts round bar packaging structure simultaneously, high-power bar-shaped crystal is difficult to bear the pumping of high-power laser, the heat effect is serious, can cause the problem of enlarging inefficiency, heat moves back partially or even causes the damage etc., is difficult to realize holistic miniaturization, modularization and engineering application. The high-power 2-micron laser developed in the prior art has lower power level and poorer beam quality.
Based on the problems, the invention improves the output power of 2 μm and the beam quality by reasonably designing the pump source and the crystal packaging structure.
In order to solve the technical problems, the invention innovatively establishes a technical approach of Tm fiber pumping Ho laser slab crystal seed light and Ho slab crystal amplification to realize high-power 2 mu m pulse laser output.
As shown in fig. 2, a 2 μm laser 100 according to an embodiment of the present invention includes: a main oscillating assembly 10 and an amplifying assembly 20.
The main oscillation component 10 uses a Tm fiber laser pumping set (such as a first Tm fiber laser 11 and a second Tm fiber laser 12 shown in fig. 2) to perform end-pumping on the main oscillation Ho slab crystal 15 to generate 2 μm seed light.
The amplifying assembly 20 adopts an angle multiplexing mode, so that 2 μm seed light passes through the amplifying stage Ho slab crystal 24 for multiple times, and under the condition of pumping by an amplifying stage Tm fiber laser pumping set (such as the Tm fiber laser 21 and the fourth Tm fiber laser 22 shown in fig. 2), 2 μm laser is extracted, and output after multi-pass amplification is realized.
According to the 2 μm laser 100 provided by the embodiment of the invention, a Tm fiber laser with the beam quality close to the diffraction limit is adopted to replace a solid laser pump source, end face pumping is carried out on a main oscillation Ho slab crystal, and 2 μm laser is extracted under the pumping condition of an amplification level Tm fiber laser pumping set in an angle multiplexing mode at an amplification component, so that multi-pass amplification and output are realized, therefore, the amplification efficiency is greatly improved while the size of the laser 100 is reduced, large-area heat dissipation can be realized by adopting the slab crystal, the thermal effect is reduced, and the output stability of the 2 μm laser is improved.
According to some embodiments of the present invention, as shown in fig. 2, the master oscillating assembly 10 comprises: tm fiber laser pump set (first Tm fiber laser 11 and second Tm fiber laser 12 shown in fig. 2), pump light coupling mirror (first coupling mirror 101 and second coupling mirror 102 shown in fig. 2), Ho laser resonator, which includes: a first total reflection mirror assembly 13, a 45-degree reflection mirror 14, a main oscillation Ho slab crystal 15, an etalon 16, a Q-switching device 17 and an output mirror system 18. The main function of the master oscillating assembly 10 is to generate 2 μm seed light of high beam quality. The Tm fiber laser pumping group performs end-face pumping on the main oscillation Ho slab crystal 15, the main oscillation Ho slab crystal 15 generates stimulated fluorescence radiation after absorbing pump light energy, and 2 μm seed light is output after amplification under the action of the Ho laser resonant cavity 13.
Wherein, the Ho laser resonant cavity adopts an L-shaped cavity, and the Q-switching device 17 adopts an acousto-optic Q-switching crystal for pulse modulation.
In some embodiments of the present invention, as shown in FIG. 2, the amplifying assembly 20 comprises: a second total-reflection mirror assembly 201, a third mirror assembly 204, a magnification stage coupling mirror (such as the third coupling mirror 241 and the fourth coupling mirror 242 shown in fig. 2), a beam transformation module 202, a polarizer 203, a 45 ° mirror (such as the first 45 ° mirror 211 and the second 45 ° mirror 212 shown in fig. 2), a magnification stage Ho slab crystal 24, a magnification stage Tm fiber laser pump set (such as the Tm fiber laser 21 and the fourth Tm fiber laser 22 shown in fig. 2), a mirror (such as the first mirror 231, the second mirror 232 shown in fig. 2), an 1/4 wave plate 23, and a lens (such as the first lens 221, the second lens 222, and the third lens 223 shown in fig. 2). The amplification level Tm fiber laser pumping group performs end pumping on the amplification level Ho slab crystal 24, performs multi-pass amplification on 2 μm seed light, and outputs the seed light from the polarizing plate 203.
The main function of the amplification component 20 is to utilize an angle multiplexing mode, the main oscillation component 10 generates 2 μm seed light of high light beam to pass through the amplification level Ho slab crystal 24 for four times, under the condition of pumping at two ends of the amplification level Tm fiber laser pumping set, 2 μm laser is extracted to realize four-pass amplification, after amplification output, the 2 μm laser is finally output from the polarizer 203, and the power of the 2 μm laser can reach more than kilowatt.
The specific process of four-way amplification of 2 μm seed light is as follows:
first-pass amplification: the 2 μm seed light output by the output mirror system 18 is reflected by the second total reflection mirror assembly 201, then sequentially transmitted to the first 45 ° mirror 211 through the beam transformation module 202 and the polarizing plate 203, then transmitted to the amplification stage Ho slab crystal 24 for the first-pass amplification, and then transmitted to the first lens 221 through the second 45 ° mirror 212.
Second-pass amplification: the first-pass amplified laser transmitted by the first lens 221 is reflected by the first reflecting mirror 231 and the second reflecting mirror 232, then transmitted to the amplification stage Ho slab crystal 24 through the second lens 222 and the second 45-degree mirror 212 for second-pass amplification, and then transmitted to the third total reflection mirror assembly 204 through the first 45-degree mirror 211, the third lens 223 and the 1/4 wave plate 23.
Third-pass amplification: the laser light which is transmitted out by the total reflection mirror 204 after the two-pass amplification passes through the 1/4 wave plate 23, the third lens 223 and the first 45-degree mirror 211 and then is transmitted to the amplification-stage Ho slab crystal 24 for the third-pass amplification, and then is transmitted to the second reflection mirror 232 after passing through the second 45-degree mirror 212 and the second lens 222.
Fourth-pass amplification: the laser light that is transmitted out of the second reflecting mirror 232 after the three-pass amplification is transmitted to the amplification stage Ho slab crystal 24 through the first reflecting mirror 231, the first lens 221, and the second 45 ° mirror 212, is amplified for the fourth pass, then passes through the first 45 ° mirror 211, and finally is output from the polarizing plate 203.
Wherein, first total anti-mirror assembly 13, second total anti-mirror assembly 201 and third total anti-mirror assembly 204 all include: two-dimensional optical adjusting frame, total reflection mirror and total reflection mirror coating filmThe parameters are as follows: light reflectivity R of wavelength of 1.9-2.1 μm 1.9-2.1μm Not less than 99.9 percent. The output mirror system 18 includes: two-dimensional optical adjustment frame, plane coupling output mirror, output mirror rete coating parameter is: light transmittance T at wavelength of 1.9-2.1 μm 1.9-2.1μm 10% -20%. The output mirror and the total reflection mirror are both made of quartz or calcium fluoride crystals and are both concave mirrors.
The 45 ° mirror 14 parameters are: light reflectivity R of 1.9-2.1 μm wavelength P 1.9-2.1μm Not less than 99.9%, s light transmittance T 1.9-2.1μm Not less than 99.9%, 2 μm narrow-band light-transmitting film coated on etalon 16, 1.9-2.1 μm anti-reflection film coated on end face of Q-switching device 17, and transmittance T 1.9-2.1μm >99.9％。
The main oscillation Ho slab crystal 15 generates stimulated fluorescence radiation after absorbing the energy of pump light of the Tm optical fiber laser 100, under the combined action of the main oscillation Ho slab crystal 15, the end surface film coating film layer of the amplification level Ho slab crystal 24, two resonant cavity mirrors and the wavelength selection of the etalon 16, the stimulated fluorescence radiation with the wavelength of 2 microns is continuously amplified and output in the resonant cavity, and the fluorescence with other wavelengths is inhibited and cannot generate laser oscillation, so that the output laser only contains light with single wavelength of 2.09 microns.
According to some embodiments of the present invention, as shown in FIG. 2, a Tm fiber laser pumping set comprises: and the pumping laser of the first Tm fiber laser 11 and the pumping laser of the second Tm fiber laser 12 are coupled into the main oscillation Ho slab crystal 15 from two ends of the main oscillation Ho slab crystal 15 respectively to carry out end face pumping.
In some embodiments of the present invention, as shown in FIG. 2, an amplifier stage Tm fiber laser pumping set comprises: and the pumping lasers of the third Tm fiber laser 21 and the fourth Tm fiber laser 22 are coupled into the amplification stage Ho slab crystal 24 from two ends of the amplification stage Ho slab crystal 24 respectively for end face pumping.
According to some embodiments of the present invention, the master oscillating Ho slab crystal 15 and the amplification stage Ho slab crystal 24 are Ho: YAG lath laser crystal with doping concentration of 0.5%. That is, the main oscillation Ho slab crystal 15 and the amplification stage Ho slab crystal 24 may be made of Ho: YAG crystal, which is bonded crystal, and has a crystal size of 2 x 70mm, a doping concentration of 0.5%, a doped region length of 60mm, and an undoped region length of 10mm (5 mm at each end).
In some embodiments of the present invention, the main oscillation Ho slab crystal 15 and the amplification stage Ho slab crystal 24 are Ho: the doping concentration of the YLF slab laser crystal is 1 percent.
According to some embodiments of the present invention, the end faces of the main oscillation Ho slab crystal 15 and the amplification-stage Ho slab crystal 24 are both coated with antireflection coating layers, and the transmittance of the antireflection coating layers to laser light in a wavelength band range of 1.9 μm to 2.1 μm is: t is 1.9-2.1 ＞99.9％。
In some embodiments of the present invention, the main oscillating Ho slab crystal 15 and the amplification stage Ho slab crystal 24 both employ heat sinks for heat dissipation. It should be noted that the main oscillation Ho slab crystal 15 and the amplification Ho slab crystal 24 are both processed into slab shapes, and heat sinks are used for heat dissipation on both sides, so that the generation of crystal thermal gradients in the pumping process is greatly reduced, the thermal lens effect of the laser crystal is reduced, and the pumping efficiency and the beam quality are improved.
According to some embodiments of the present invention, the laser light in the amplification stage Ho slab crystal 24 propagates in a zigzag fashion. The schematic diagram of the laser transmission inside the panel is shown in fig. 4.
In order to make a laser oscillator output extremely high power or energy, the volume of a laser working substance needs to be increased, but it is very difficult to manufacture a large-volume solid laser material having good optical uniformity, and a high-power or high-energy laser oscillator often has difficulty in generating a laser beam having excellent performance (such as a divergence angle, monochromaticity, and a pulse width). In addition, the back and forth transmission of high power (energy) laser beams within the resonant cavity can also cause damage to the working substance and optical components within the cavity. Thus, high quality, high power (energy) lasers are obtained, and laser amplification techniques are the best choice.
The use of an oscillator-amplifier architecture (MOPA) is an effective way of output scaling amplification, which can achieve both high output power and good beam quality, since in MOPA laser systems the laser output index is mainly dependent on the main oscillator laser. The laser with high beam quality is used as an oscillation stage, the slab gain medium is an MOPA structure of an amplification stage, and the multi-angle multiplexing of the amplification stage is realized by utilizing the polarization characteristic of the oscillation stage laser, so that the multi-pass amplification of the slab laser can be realized, and the laser source with high energy and high beam quality can be obtained.
The rod-shaped crystal is adopted for MOPA amplification, 200W 2 mu m laser output is realized, three-to-four-stage amplification is adopted for realization, but the volume is extremely large, and if the prior art is used for calculation, the rod-shaped crystal is adopted for realizing the laser output of more than kilowatt level, and the volume is 4-5 times of the realized volume. A schematic diagram of a rod-shaped crystal and plate-shaped crystal package comparison is shown in fig. 5.
Adopt the lath mode to carry out MOPA and enlarge, enlarge the light path and carry out the zigzag and propagate in the lath crystal, make full use of the size of crystal, enlarge the light path and will be several times of the same size pole, utilize laser polarization characteristic, the amplifier stage can the multi-angle multiplex, greatly promote the amplification efficiency when reducing 100 volumes of laser instrument, adopt the lath crystal to also realize the large face heat dissipation, adopt the microchannel structure simultaneously, greatly reduce the heat effect.
The 2 μm laser 100 according to the invention is described in detail below in two specific embodiments with reference to the drawings. It is to be understood that the following description is illustrative only and is not to be construed as limiting the invention in particular.
The first embodiment is as follows:
as shown in fig. 2, the overall optical path structure of a high-power 2 μm solid-state laser 100, the laser 100 is mainly composed of an end-pumped main oscillation module 10 and an amplification module 20.
The main oscillation component 10 is provided with a first total reflection mirror component 13, a main oscillation Ho slab crystal 15, a 45-degree reflector 14, an etalon 16, a Q-switching device 17 and an output mirror system 18 in sequence on a light path, and a first Tm fiber laser 11 and a second Tm fiber laser 12 respectively enter the crystal through coupling mirrors at two ends of the main oscillation Ho slab crystal 15 to perform end face pumping, and the main function is to generate 2 mu m seed light with high beam quality.
The main oscillation Ho slab crystal 15 generates stimulated fluorescence radiation after absorbing light energy pumped by a Tm fiber laser, the stimulated fluorescence radiation with the wavelength of 2 mu m is continuously amplified and output in the resonant cavity under the combined action of the end face coating film layer of each laser crystal, the two resonant cavity mirrors and the wavelength selection of the etalon 16, and fluorescence with other wavelengths is inhibited and cannot generate laser oscillation, so that the output laser only contains light with a single wavelength.
The main oscillation Ho slab crystal 15 is made of Ho: YAG crystal, which is bonded crystal, and has a crystal size of 2 x 70mm, a doping concentration of 0.5%, a doped region length of 60mm, and an undoped region length of 10mm (5 mm at each end).
The resonant cavity adopts an L-shaped cavity, and the Q-switching device 17 adopts acousto-optic Q-switching crystal for pulse modulation. The output mirror and the total reflection mirror are both made of quartz or calcium fluoride crystals and are both concave mirrors.
The amplifying assembly 20 comprises a second total-reflection mirror assembly 201, a light beam conversion module 202, a polarizing plate 203, a first 45-degree mirror 211, an amplifying-stage Ho slab crystal 24 and a second 45-degree mirror 212 which are sequentially arranged on a light path, a third Tm fiber laser 21, a fourth Tm fiber laser 22 and a coupling mirror are respectively arranged on two sides of the amplifying-stage Ho slab crystal 24, a third lens 223, a wave plate 1/4 and a third total-reflection mirror assembly 204 are sequentially arranged above the first 45-degree mirror 211, and a first lens 221, a first reflecting mirror 231, a second lens 222 and a second reflecting mirror 232 are sequentially arranged below the second 45-degree mirror 212. The third Tm fiber laser 21 and the fourth Tm fiber laser 22 are coupled to the crystal through coupling mirrors at two ends of an amplification stage Ho slab crystal 24, respectively, and enter the crystal for end pumping, and the main oscillation laser is amplified in four passes and finally output from the polarizer 203.
Wherein, amplifier level Ho lath crystal 24 produces 2 μm stimulated fluorescence radiation after absorbing Tm fiber laser pump light energy, and 2 μm main oscillation light passes through quartic lath crystal, realizes the four-way amplification, and amplifier level Ho lath crystal 24 body material is Ho: YAG crystal, it adopts bonded crystal, crystal 2 x 4 x 100mm, doping concentration is 0.5%, doping region length is 90mm, non-doping region length is 10mm (both ends are 5mm each, end face is 45 degree inclined plane, is plated with 1.9-2.1 μm antireflection coating).
Example two:
as shown in fig. 3, unlike the first embodiment, in the present embodiment, both the main oscillation Ho slab crystal 15 and the amplification-stage Ho slab crystal 24 are Ho: YLF slab laser crystal. The rest of the process is the same as the first embodiment, and will not be described herein.
While the invention has been described in connection with specific embodiments thereof, it is to be understood that it is intended by the appended drawings and description that the invention may be embodied in other specific forms without departing from the spirit or scope of the invention.
Claims (10)
1. A 2 μm laser, comprising:
the main oscillation component adopts a Tm fiber laser pumping group to perform end-face pumping on a main oscillation Ho slab crystal to generate 2 mu m seed light;
and the amplification component adopts an angle multiplexing mode, so that the 2 mu m seed light passes through the amplification level Ho slab crystal for multiple times, and extracts 2 mu m laser under the condition of pumping of the amplification level Tm fiber laser pumping set, thereby realizing multi-pass amplification and output.
2. The 2 μm laser according to claim 1, wherein the master oscillator component comprises: tm fiber laser pump group, pump optical coupling mirror, Ho laser resonator includes: the device comprises a first full-reflection mirror assembly, a 45-degree reflection mirror, a main oscillation Ho slab crystal, an etalon, a Q-switching device and an output mirror;
the Tm fiber laser pumping group performs end face pumping on the main oscillation Ho slab crystal, the main oscillation Ho slab crystal generates stimulated fluorescence radiation after absorbing pump light energy, and 2 mu m seed light is output after being amplified under the action of the Ho laser resonant cavity.
3. The 2 μm laser of claim 1, wherein the amplifying assembly comprises: the device comprises a second full-reflection mirror assembly, a third full-reflection mirror assembly, an amplification stage coupling mirror, a beam transformation module, a polaroid, a 45-degree mirror, an amplification stage Ho slab crystal, an amplification stage Tm fiber laser pumping set, a reflector, an 1/4 wave plate and a lens;
and the amplification level Tm fiber laser pumping group performs end face pumping on the amplification level Ho slab crystal, and outputs the 2 mu m seed light from a polaroid after multi-pass amplification.
4. The 2 μm laser of claim 1, wherein the Tm fiber laser pumping set comprises: and the pumping lasers of the first Tm fiber laser and the second Tm fiber laser are respectively coupled into the main oscillation Ho slab crystal from two ends of the main oscillation Ho slab crystal to carry out end face pumping.
5. The 2 μm laser of claim 1, wherein the amplification stage Tm fiber laser pumping group comprises: and the pumping lasers of the third Tm fiber laser and the fourth Tm fiber laser are respectively coupled into the amplification stage Ho slab crystal from two ends of the amplification stage Ho slab crystal to carry out end face pumping.
6. The 2 μm laser according to claim 1, wherein the master oscillating Ho slab crystal and the amplifying stage Ho slab crystal are Ho: YAG lath laser crystal with doping concentration of 0.5%.
7. The 2 μm laser according to claim 1, wherein the master oscillating Ho slab crystal and the amplifying stage Ho slab crystal are Ho: the doping concentration of the YLF slab laser crystal is 1 percent.
8. The 2 μm laser according to any one of claims 1 to 7, wherein end faces of the main oscillation Ho slab crystal and the amplification Ho slab crystal are each coated with an antireflection film layer having a transmittance for laser light in a wavelength band range of 1.9 μm to 2.1 μm of: t is 1.9-2.1 ＞99.9％。
9. The 2 μm laser as claimed in any one of claims 1 to 7, wherein the main oscillation Ho slab crystal and the amplification stage Ho slab crystal are heat-dissipated using a heat sink.
10. The 2 μm laser according to any of claims 1-7, wherein the laser light in the amplification stage Ho slab crystal propagates in a zigzag shape.
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| CN202210338651.6A CN114883896A (en) | 2022-04-01 | 2022-04-01 | 2 mu m laser |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116667120A (en) * | 2023-05-16 | 2023-08-29 | 齐鲁中科光物理与工程技术研究院 | Compact self-injection type double-pass pulse laser amplifier |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102842849A (en) * | 2012-09-19 | 2012-12-26 | 哈尔滨工业大学 | High power 3 mum -5mum wave band solid laser of optical fiber laser pump |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102842849A (en) * | 2012-09-19 | 2012-12-26 | 哈尔滨工业大学 | High power 3 mum -5mum wave band solid laser of optical fiber laser pump |
Non-Patent Citations (1)
| Title |
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| 刁伟鹏 等: ""高重频大能量亚纳秒板条激光放大器研究"" * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116667120A (en) * | 2023-05-16 | 2023-08-29 | 齐鲁中科光物理与工程技术研究院 | Compact self-injection type double-pass pulse laser amplifier |
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