54results about How to "Reduce Thermal Lensing" patented technology

The invention discloses an Er<3+> / Yb<3+> co-doped yttrium lithium fluoride monocrystal and a preparation method thereof. The yttrium lithium fluoride monocrystal is a rare earth ion Er<3+> / Yb<3+> co-doped monocrystal; the molecular formula is LiY(1-x-y)ErxYbyF4, wherein x is greater than or equal to 0.008 and less than or equal to 0.085, and y is greater than or equal to 0.002 and less than or equal to 0.170; the segregation coefficients of Yb<3+> and Er<3+> in the yttrium lithium fluoride are about 1, and efficient intermediate infrared laser of 2.7 microns can be output; and the yttrium lithium fluoride monocrystal has high transmittance of intermediate infrared laser, has better thermal, mechanical and chemical stabilities than those of glass state materials and has the characteristics of low phonon energy, high optical transmittance of wavebands with width of 300-5500nm, less color center forming amount, low thermal lens effect and the like, thereby being more easily processed and more suitably used in laser devices. In the preparation method disclosed by the invention, a sealing crucible falling technology is used, so that the operation is simple; the raw material is fluorated at high temperature in a sealed water-free and oxygen-free environment, so that the crystal is isolated from air and water vapor during the growth; and therefore, the high-quality Er<3+> / Yb<3+> co-doped LiYF4 monocrystal containing little OH<-> ion and oxide is obtained.

The invention provides a semiconductor side pumping module. By adopting the multidirectional even pumping technology, the side wall of a guide quartz tube is provided with a high reflection film and an anti-reflection film by segmenting for pumping light to reduce the loss of the pumping light; and a laser crystal combining a screw thread manufactured on the lateral surface and an un-doped matrix bonded on the end face is adopted for improving the absorption efficiency of the pumping light and reducing the end face effect and thermal lens effect of the laser crystal so as to improve the conversion efficiency and light beam quality of a laser. The guide quartz tube respectively adopts segmented film coating and non film coating on the side wall to carry out test comparison; when the pumping power is 1KW, the segmented film coating efficiency is improved by 16 percent compared with the non film coating efficiency; and in the state that the guide quartz tube is not coated with a film, when the pumping power is 1KW, the conversion efficiency of the laser crystal combining the screw thread manufactured on the lateral surface and the un-doped matrix bonded on the end face is improved by 9 percent compared with a common laser crystal, the thermal focal distance is shortened by about 12 percent, and the light beam quality M value is reduced by 17 percent.

The invention discloses a frequency doubling self-regulating Q green laser inside a double-doped chrome yttrium aluminum garnet composite photassium titanyl phosphate cavity,and relates to a green laser. The self-regulating Q green laser is provided with a pumping source, a micro lens, a first column-shaped lens, a second column-shaped lens and a laser working medium Cr, Nd:YAG / KTP composite crystal. The pumping source, a micro lens, the first column-shaped lens, the second column-shaped lens and the laser working medium Cr, Nd:YAG / KTP composite crystal sequentially are arrayed on a same plain shaft from front to back. Anti-reflection film and a high-reflective film are plated on the rear surface of the laser working medium Cr, Nd:YAG / KTP composite crystal to serve as a back cavity lens of the laser cavity. High-reflective film and anti-reflection film are plated on the front surface of the laser working medium Cr, Nd:YAG / KTP composite crystal of the laser cavity. The number of optical elements used for the laser is small, the production cost is low, the structure is simple and compact, and the laser is convenient to produce and assemble and operate and use by a non-professional person.

The invention provides a flake type semiconductor laser pumping alkali metal laser system. The laser system is able to speed up steam medium radiating speed and further lighten the temperature gradient distribution of a steam cavity. The flake type semiconductor laser pumping alkali metal laser system is realized through the following technical scheme: a semiconductor laser light source is narrowed through a pumping light line-width narrowing system, and then coupled by a pumping light beam homogenizing collimating system to enter an alkali metal steam cavity filled with alkali metal medium and buffer gas, so as to match up with the pumping line-width and absorbing line-width of an alkali metal atom; the pumping light beam homogenizing collimating system homogenizes and absorbs the pumping light; a pumping light reflecting system reflects the unabsorbed pumping light for many times to the alkali metal steam cavity; an alkali metal steam temperature control system is closed to a back end face of the alkali metal steam cavity; a planar and large-area temperature control method is applied to speed up the heat transmission in axial direction and reduces the temperature gradient distribution of the steam cavity in cross direction; a laser is oscillated in a laser resonate cavity to output.

The invention discloses an Er<3+> / Pr<3+> co-doped yttrium lithium fluoride monocrystal and a preparation method thereof. The yttrium lithium fluoride monocrystal is a rare earth ion Er<3+> / Pr<3+> co-doped monocrystal; and the molecular formula is LiY(1-x-y)ErxPryF4, wherein x is greater than or equal to 0.010 and less than or equal to 0.085, and y is greater than or equal to 0.0001 and less than or equal to 0.008. The yttrium lithium fluoride monocrystal has the advantages of high emission efficiency of fluorescence of 2.7 microns and high transmittance in intermediate infrared ray, has better thermal, mechanical and chemical stabilities than those of glass state materials and has the characteristics of low phonon energy, high optical transmittance of wavebands with width of 300-5500nm, less color center forming amount, low thermal lens effect and the like, thereby being more easily processed and more suitably used in laser devices. In the preparation method disclosed by the invention, a sealing crucible falling technology is used, so that the operation is simple; the raw material is fluorated at high temperature in a sealed water-free and oxygen-free environment, so that the crystal is isolated from air and water vapor during the growth; and therefore, the high-quality Er<3+> / Pr<3+> co-doped LiYF4 monocrystal containing little OH<-> ion and oxide is obtained.

The invention discloses a novel bicrystal tandem connection dual-wavelength laser, and relates to the field of electronic devices, in particular to the field of full-solid dual-wavelength lasers. Dual-wavelength lasers are simultaneously output through a same light path, wherein dual wavelengths include the first wavelength of sigma polarization and the second wavelength of pi polarization. The laser mainly comprises an anisotropy laser crystal, a pumping source for generating the inversion particle number through the laser crystal and a dual-wavelength laser resonance cavity for achieving dual-wavelength oscillating. The novel cross-polarization dual-wavelength laser serves as a novel laser source, the technological difficulty of high-conversion-efficiency and high-light-beam-quality linear polarization dual-wavelength laser output is overcome, a novel technological approach is provided for obtaining high-power and high-coherent-terahertz radiation, application of cross-polarization dual-wavelength laser light is expanded, and the wide market application prospect is obtained in the fields such as laser communication.

The invention discloses an all-solid-state single-frequency tunable red laser. The all-solid-state single-frequency tunable red laser comprises a laser diode, a pumping light shaping system, a resonant cavity, a gain medium, a frequency doubling crystal, a magneto-optical isolator and a frequency tuning device, wherein the laser diode is connected with the pumping light shaping system by virtue of optical fibers, light spots shaped by the pumping light shaping system are longitudinally pumped onto the gain medium, and fluorescence, excited with an infrared band, of the gain medium enters the resonant cavity. With the adoption of the all-solid-state single-frequency tunable red laser, the frequency continuous regulation of a 671nm red light is realized by the matching of an F-P etalon and piezoelectric ceramic, wherein the F-P etalon is used for crude regulation, and the piezoelectric ceramic is used for fine regulation; compared with a traditional 808nm pumping source, a 880nm pumping source adopted by the laser has the advantages that thermal lens effect of the crystal can be effectively reduced, and the conversion efficiency of the laser is improved; as the laser is in an annular cavity structure, the running is efficient and stable.

The invention relates to a holmium-doped gadolinium-yttrium-barium fluoride crystal and a growth method thereof, belonging to the technical field of optoelectronic materials. The conventional Ho:BaY2F8 crystal has low doping concentration, small size and bad crystal morphology. The holmium-doped gadolinium-yttrium-barium fluoride crystal belongs to a monoclinic system, rare earth element holmium is used as active ions, a crystal matrix is gadolinium-yttrium-barium fluoride, and the molecular formula of the holmium-doped gadolinium-yttrium-barium fluoride crystal is Ho:BaYGdF8. The growth method for the holmium-doped gadolinium-yttrium-barium fluoride crystal comprises the following three steps of: preparing a growth material, performing crystal growth and annealing. In the step of preparing the growth material, elements such as F, Gd, Y and Ba served as raw materials are provided in a molar ratio of BaF2: GdF3: YF3 equal to 1:1:1, HoF3 is determined as x mol, GdF3 is determined as (1-x) mol, BaF2 is determined as 1 mol, and the value scope of the x is more than or equal to 0.005 mol and less than or equal to 1 mol; and in the step of performing the crystal growth, process parameters for the crystal growth are determined as follows: the withdrawal pulling rate is between 0.3 and 0.8mm / h, the rotation speed is between 3 and 10rmp, and the growth temperature is between 880 and 903 DEG C.

The invention provides a high-power intracavity frequency-doubled single-frequency laser device. The high-power intracavity frequency-doubled single-frequency laser device comprises a pumping source (5), a gain crystal (6), an annular resonant cavity, a one-way device and a frequency doubling crystal (9), wherein a first flat concave mirror (1) constituting the annular resonant cavity is plated with a film which allows base-frequency light to transmit to a certain degree and allows frequency-doubling light to transmit easily, the first flat concave mirror (1) constitutes the annular resonant cavity of the laser device on one hand, the thermal lens effect of a TGG crystal (7) constituting the one-way device can be adjusted and controlled by adjusting and controlling the intracavity power density of the laser device by means of the plated film on the other hand, and thus efficient and high-power single-frequency operation of the laser device is achieved. According to the high-power intracavity frequency-doubled single-frequency laser device, the influence of the thermal lens effect of the TGG crystal (7) on the laser device is reduced on the basis that the output power of the laser device is not affected, and thus the laser device can operate more stably on the basis that high output power can be obtained through the laser device.

The invention discloses a novel Raman cell capable of reducing the thermal lens effect of high repetition frequency pump light during a gaseous medium propagation process. In the design, the outermostRaman cell wall is made of stainless steel, and a three-dimensional filler is disposed in the Raman cell. Gaps between the outer wall of the Raman cell and the built-in filler can be filled with a high-pressure gas, and have inconsistent widths. A fan unit is placed in one of narrow gaps. One of the remaining narrow gaps is selected as a light passage of the pump light. When high repetition frequency pump light is configured to pump a gaseous medium, the heat in the vicinity of the pump light gradually accumulates and generates a thermal lens effect to affect the beam quality of the output light. After an electric fan operates, the high-pressure gaseous medium in the gaps flows in a fixed direction, takes away the heat in the vicinity of the pump light, reduces the thermal lens effect inthe Raman cell so as to improve the conversion efficiency of Raman light. The novel Raman cell improves the Raman light conversion efficiency and beam quality by reducing the thermal effect, and has bright application prospects.

The invention provides a method for precisely machining a deep groove and a deep hole by varifocal lasers. The method comprises the steps that a plurality of focusing lenses with different focal lengths and workpieces are clamped; if deep groove machining is carried out, a laser beam is continuously output; laser etching machining is completed once; if deep hole machining is carried out, N laser pulses are output; the lasers are closed, and a working table moves to the original position; whether machining meets the requirements or not is detected; if machining meets the requirements, machining is finished; if machining does not meet the requirements, a focusing lens base is rotated, the next focusing lens is moved to the position of the current focusing lens, and laser machining is carried out again until machining meets the requirements. The pulse laser beam sequentially penetrates through the focusing lenses with the different focal lengths by rotating the focusing lens base, the focal lengths are progressively changed, the lasers are focused on the new exposed surface in the laser etching or punching process all the time, energy is more concentrated, the punching deep is larger, and the efficiency is higher. The invention provides a device for precisely machining the deep groove and the deep hole by the varifocal lasers at the same time.

The invention discloses a Ho<3+> / Pr<3+> codoping lithium yttrium fluoride monocrystal and a preparation method thereof. The lithium yttrium fluoride monocrystal is a rare-earth iron Ho<3+> / Pr<3+> codoping monocrystal; the molecular formula of the lithium yttrium fluoride monocrystal is LiY(1-x-y)HoxPryF4, wherein x is more than and equal to 0.004 or less than and equal to 0.08, and y is more than and equal to 0.0002 or less than and equal to 0.01. The lithium yttrium fluoride monocrystal disclosed by the invention has the characteristics of high efficiency of 2.9 mu m fluorescence emission, high intermediate-infrared transmittance, more excellent thermotic, mechanical and chemical stability compared with those of a glass-state material, low phonon energy, high optical transmissibility at a 300-5500 nanometer broadband, small color center forming amount, low thermal lens effect, and the like, and is easier to process and more suitable for a laser device. The preparation method disclosed by the invention adopts a sealing crucible descent method technology, is easy to operate, carries out high-temperature fluorination treatment on a raw material and obtains the high-quality Ho<3+> / Pr<3+> codoping LiYF4 monocrystal almost without -OH ions or oxides by insulating the monocrystal from air and vapors in the growing process by adopting a water-insulated oxygen-insulated sealing environment.

The invention provides a cooling system for a crystal used by a laser. The cooling system is provided with a cooling interface device, a vacuum device interface, a temperature measuring device interface and installation interfaces of a brewster form, wherein the cooling interface device is externally connected with a cryogenic cooling system, the vacuum device interface is externally connected with a vacuum system and the temperature measuring device interface is externally connected with a temperature control feedback system. The external cryogenic cooling system that is connected with the cooling interface device provides a stable low-temperature environment for a crystal inside a vacuum chamber. The external vacuum system that is connected with the vacuum device interface provides a vacuum heat insulation environment for the crystal inside the vacuum chamber. The temperature control feedback system that is connected with the temperature measuring device interface carries out real-time feedback and regulation and control on the crystal temperature. And temperature control sheets that are installed near the installation interfaces of the brewster form are used for adjusting steam partial pressures around the brewster form to be below a condensation point. Therefore, according to the invention, thermal conductivity of the crystal used by a laser is increased; the thermal gradient is reduced; and a thermal lens effect is reduced; meanwhile, an occurrence of a condensation phenomenon can be avoided and normal work of the whole laser can be ensured.

An electro-optical Q laser used for high speed glass processing comprises a laser diode which possesses a driving power supply and output coupling fiber with 880nm output wavelength. A first plane-convex lens, a second plane-convex lens, a back-cavity mirror, a laser medium, polaroid, an electro-optical Q switch, a lambda / 4 wave plate, a 45-degree reflector, a 45-degree transmission-reflection mirror, frequency doubling crystal and a front cavity mirror are successively arranged along a laser direction output by the coupling fiber. The wavelength of the output green ray of the laser is 532nm. Average output maximum power is 11 watt. The highest frequency reaches more than 100KHz. Maximum single pulse energy is greater than 1mJ. A laser pulse width is less than 5ns. A light beam quality factor M<2> is less than or equal to 1.2. The laser of the invention can be used for applications, such as high speed etching on a glass surface, drilling, cutting and the like.

The invention discloses a micro-channel metal foam disk laser crystal cooling device, which comprises a disk laser crystal, metal foams and a micro-channel plate water circulation system, wherein the pore diameter of the metal foams is within 0.5 mm, and a copper tungsten material is selected. The micro-channel metal foam disk laser crystal cooling device has the advantages that the foam metal cooling device is delicately introduced to a disk laser crystal back cooling field, the metal foam structure features and the micro-channel water circulation system are mutually combined thoroughly, the cooling water can cool the disk crystal uniformly, and the crystal cooling efficiency is greatly enhanced.

The invention discloses a miniaturized human eye safety pulse laser. The pulse laser comprises a laser diode, a shaping coupling system, a resonant cavity, an optical window sheet and a shell; the laser diode emits pump light with the central wavelength of 940-980 nm, or 1.47 [mu]m, or 1.53 [mu]m, and the divergent pump light enters the resonant cavity after passing through the shaping coupling system; the shaping coupling system consists of two convex lenses and is used for realizing collimation and size adjustment of the pump light beam; the resonant cavity is used for generating pulse humaneye safety laser with the wavelength of 1.6 [mu]m; the optical window sheet is a laser-emitting window, and the surface of the window is plated with an antireflection film with the wave band of 1.6 [mu]m; and the shell is made of a metal material, and the laser diode, the shaping coupling system, the resonant cavity and the optical window sheet are all fixed on the shell. A new technical means for realizing high-peak-power and high-energy giant pulse output with low pumping power is adopted, and the whole laser is compact in design structure, stable, durable, miniature, convenient to carry and applicable to various scenes.

The invention discloses a method and system for improving the energy and efficiency of an Er: YAG single-frequency solid-state laser, belonging to the technical field of laser. In order to reduce theinfluence of a thermal lens effect and upper energy level effect on laser output, Er: YAG crystal or ceramic with low doping concentration is the first choice of a gain medium. However, due to its lowdoping concentration, in order to achieve high-power and high-energy single-frequency laser output, it is usually necessary to inject a single-frequency seed laser into Q-switched pulsed slave laserand one or more amplifiers. The invention discloses a system for improving the energy and efficiency of an Er: YAG single-frequency solid-state laser, which can obtain a single-frequency laser outputwith large energy in a seed injection mode. The invention can not only solve the problem that the output efficiency of the high-energy single-frequency laser output is low due to adoption of a high-power pumping source and increase of the doping concentration of the gain medium, but also avoids the complex system caused by excessive amplification structure, thereby facilitating the realization ofsmall-sized large-energy single-frequency laser output.

The invention discloses a cooling system based on a slab laser. The cooling system performs directional conductive water-cooling-free heat dissipation on the basis of crystal shape of the slab laser,and comprises a neodymium-doped yttrium vanadate crystal, highly thermal conductive heat sinks and electronic borneol, wherein the neodymium-doped yttrium vanadate crystal is a pumping source of the laser; the highly thermal conductive heat sinks are arranged on two sides of the neodymium-doped yttrium vanadate crystal; the electronic borneol is arranged on outer sides of the highly thermal conductive heat sinks. Heat produced by the neodymium-doped yttrium vanadate crystal is transmitted to the bottom surface of metal indium from the top surface, then is transmitted to a base and a housing ofthe laser through the electronic borneol and thermal conductive copper pipes and is finally input into a work environment. According to the scheme, a water-cooling-free manner is adopted, the heat isdissipated in a directional transmission manner through thermal conduction, the overall length of the length is reduced greatly, and the laser is more flexible and can be used under conditions with difficulties in water cooling such as weightlessness and the like.

The invention discloses a semiconductor pump laser, which includes a semiconductor laser pump source, an optical coupling system and a laser cavity. The laser cavity includes front and rear cavity plates, a laser gain medium, and optical elements other than the laser gain medium, wherein the laser gain The medium is composed of two or more laser gain media with different doping ion concentrations or different absorption coefficients. Different laser gain media are arranged in ascending order of doping ion concentration or absorption coefficient along the incident direction of pump light. The laser gain medium with low impurity ion concentration absorbs part of the pump light, and the other part of the pump light passes through the low-doped laser gain medium and is pumped and absorbed by the laser gain medium with high dopant ion concentration, reducing the The thermal lens effect of the laser gain medium can enhance the absorption of pump light at the same time, so as to obtain a semiconductor-pumped laser suitable for wide pump wavelength range and wide temperature operation.

The invention relates to an end face pump green-light laser which comprises a V-type folding cavity, a coupling and focusing system, a pump unit, a laser crystal, a frequency doubling crystal and a Q adjusting device. The end face pump green-light laser adopts a V-type folding optical circuit structure; basic frequency light produced by a resonant cavity is subjected to frequency doubling through the frequency doubling crystal in the cavity to produce frequency doubling light; and the frequency doubling light is output. The laser has reasonable design, novel conception, a normative process, a compact structure and no pollution, is suitable for industrialized batch production, and can be widely applied to communication, precise electron and other fields.

The invention discloses a laser regenerative amplifier based on a disc gain medium. The laser regenerative amplifier comprises a seed light source, an optical fiber coupling collimation module, a regenerative amplification resonant cavity, a pumping module and an optical isolator, wherein the regenerative amplification resonant cavity comprises a first polaroid, a Faraday rotator, a 1 / 2 wave plate, a second polaroid, a Pockels cell, a 1 / 4 wave plate, a first cavity mirror, a third cavity mirror, a fourth cavity mirror, a fifth cavity mirror, a disc gain medium, a seventh cavity mirror and an eighth cavity mirror, the first cavity mirror, the third cavity mirror and the fifth cavity mirror are concave mirrors, and the fourth cavity mirror, the seventh cavity mirror and the eighth cavity mirror are plane mirrors. Seed light oscillates in the regenerative amplification resonant cavity in a reciprocating mode, energy is amplified after the seed light passes through the disc gain medium every time, the lower thermal lens effect is achieved, the amplification efficiency linearization degree and the pulse stability are high, and extremely high light beam quality can be guaranteed.

The invention relates to a multi-path tail end pump narrow pulse-width slice solid laser which comprises a first full reflection mirror (1), a dichroic mirror I (2), a crystal slice (3), a dichroic mirror II (4), a dichroic mirror III (5), a dichroic mirror IV (6) and an output mirror (7). Pulse-width compression is performed on a first pump light by a first pulse-width compression device (12), pulse-width compression is performed on a second pump light by a second pulse-width compression device (14), pulse-width compression is performed on a third pump light by a third pulse-width compressiondevice (13), pulse-width compression is performed on a fourth pump light by a fourth pulse-width compression device (15), then pulse-width compression is performed on an oscillation light in a resonant cavity by a fifth pulse-width compression device (8) and performed on the oscillation light outside the resonant cavity by a sixth pulse-width compression device (9), the oscillation light is injected into an oscilloscope (10), a computer forms control signals, so that pulse width is automatically adjusted, and picometer-level pulse-width laser output is achieved.

The invention discloses a laser processing head based on multiple optical fiber output laser modules. The laser processing head comprises the optical fiber output laser modules, a plurality of collimating lenses corresponding to the optical fiber output laser modules one to one, a focusing lens, an optical fiber support, a collimating lens support, a focusing lens support and a tubular shell. Theoutput ends of output optical fibers of the optical fiber output laser modules are fixed to the optical fiber support. The collimating lens comprises at least one lens fixed to the collimating lens support. The focusing lens comprises at least one lens fixed to the focusing lens support. The optical fiber support is fixed in the tubular shell and is close to one end, and the output end faces of the optical fibers face the other end of the tubular shell. A high-power optical fiber beam combiner does not need to be used, the size of the collimating lens is greatly reduced, the cooling effect isimproved, and the thermal lens effect is reduced; and the heat dissipation capability of the focusing lens is greatly improved, the thermal lens effect is reduced, and the processing beam quality is improved.

The invention discloses a spectral body capable of improving laser photoelectric conversion efficiency and optical quality. The spectral body refers to a spectrum isolation plate, which is arranged between a xenon lamp and a crystal, and is made of cerium-doped quartz glass. One surface of the spectrum isolation plate is plated with a total-reflection film for isolating infrared light with a wavelength from 0.87 to 1.2 mu m. The other surface of the spectrum isolation plate is plated with a layer of an optical substance used for absorbing light with a wavelength from 0.6 to 0.7 mu m and capable of converting the light into light with a wavelength from 0.8 to 0.9 mu m. The spectral body adopts a spectrum conversion method according to absorption features of the YAG laser crystal, increases the component of spectra useful for the laser crystal, isolates the component of harmful bands, improves the efficiency of laser photoelectric conversion and improves the optical quality of laser output. Through the two conversions, the laser efficiency can be increased by 40% or more, the thermal lens effect of the crystal is reduced, the beam quality is significantly improved, and the effect is remarkable for forming high-power laser devices.

The invention discloses an Er<3+> / Yb<3+> co-doped yttrium lithium fluoride monocrystal and a preparation method thereof. The yttrium lithium fluoride monocrystal is a rare earth ion Er<3+> / Yb<3+> co-doped monocrystal; the molecular formula is LiY(1-x-y)ErxYbyF4, wherein x is greater than or equal to 0.008 and less than or equal to 0.085, and y is greater than or equal to 0.002 and less than or equal to 0.170; the segregation coefficients of Yb<3+> and Er<3+> in the yttrium lithium fluoride are about 1, and efficient intermediate infrared laser of 2.7 microns can be output; and the yttrium lithium fluoride monocrystal has high transmittance of intermediate infrared laser, has better thermal, mechanical and chemical stabilities than those of glass state materials and has the characteristics of low phonon energy, high optical transmittance of wavebands with width of 300-5500nm, less color center forming amount, low thermal lens effect and the like, thereby being more easily processed and more suitably used in laser devices. In the preparation method disclosed by the invention, a sealing crucible falling technology is used, so that the operation is simple; the raw material is fluorated at high temperature in a sealed water-free and oxygen-free environment, so that the crystal is isolated from air and water vapor during the growth; and therefore, the high-quality Er<3+> / Yb<3+> co-doped LiYF4 monocrystal containing little OH<-> ion and oxide is obtained.

The invention discloses an Er<3+> / Pr<3+> co-doped yttrium lithium fluoride monocrystal and a preparation method thereof. The yttrium lithium fluoride monocrystal is a rare earth ion Er<3+> / Pr<3+> co-doped monocrystal; and the molecular formula is LiY(1-x-y)ErxPryF4, wherein x is greater than or equal to 0.010 and less than or equal to 0.085, and y is greater than or equal to 0.0001 and less than or equal to 0.008. The yttrium lithium fluoride monocrystal has the advantages of high emission efficiency of fluorescence of 2.7 microns and high transmittance in intermediate infrared ray, has better thermal, mechanical and chemical stabilities than those of glass state materials and has the characteristics of low phonon energy, high optical transmittance of wavebands with width of 300-5500nm, less color center forming amount, low thermal lens effect and the like, thereby being more easily processed and more suitably used in laser devices. In the preparation method disclosed by the invention, a sealing crucible falling technology is used, so that the operation is simple; the raw material is fluorated at high temperature in a sealed water-free and oxygen-free environment, so that the crystal is isolated from air and water vapor during the growth; and therefore, the high-quality Er<3+> / Pr<3+> co-doped LiYF4 monocrystal containing little OH<-> ion and oxide is obtained.

The invention discloses an end face pumping Q-switched laser based on a doping concentration gradient crystal. The end face pumping Q-switched laser is characterized in that the doping concentration of a laser working substance is exponentially increased along a light transmission direction, a pumping light incident plane, namely a pumping end face, is a low-concentration end, and a non-pumping light incident plane is a high-low-concentration end; the laser working substance is an Nd <3+>-doped crystal; a laser resonant cavity is an L-shaped folding cavity, and the folding angle is 90 degrees; and the curvature radius of a plano-convex total reflection mirror and the curvature radius of an output cavity mirror are designed according to the thermal focal length value of the thermal lens effect of the laser working substance and the structure of the laser resonant cavity. According to the invention, the distribution of pumping light and heat in the laser working substance is more uniform, the thermal lens effect is reduced, the laser output power is improved, the uniformity and stability are better, the laser conversion efficiency is improved, and the beam quality of the output laser is improved.

The invention discloses a high-power, small-sized, water cooling-free and side pump slab laser device. A total reflector, a Q switch unit, a polarizer, a pumping module, and an output coupling mirrorare sequentially and coaxially disposed in the direction of laser beam propagation of the device; the total reflector and the output coupling mirror form a resonant cavity, and the total reflector isthe total reflector with 1064 nm; and the Q switch unit is any one of an active Q switch crystal or a voltage-decreased photoelectric Q switch equipped with a feedback control circuit. In the high-power, small-sized, water cooling-free and side pump slab laser device, except non-pumped surface heat dissipation on both faces, two pump faces are also subjected to staggered heat dissipation by a gold-plated copper reflection block, and so, the uniformity of heat dissipation of a double-sided pump laser crystal is ensured, the thermal lens effect of the double-sided pump laser crystal is reduced,wavefront edge distortion of the laser device is effectively improved, and the laser device performs temperature control by adopting a TEC thermoelectric cooler, so that the weight of the laser deviceis effectively reduced.

The invention discloses an end face uniform pumping type solid laser device. First pumping light is emitted through a first laser pumping source assembly; after the first pumping light penetrates through a heat compensation negative lens and a second pumping source reflecting mirror in sequence, the first pumping light is emitted and focused to a first focusing point in a laser crystal; a second laser pumping source assembly emits second pumping light; after the second pumping light is reflected through the second pumping source reflecting mirror, the second pumping light is emitted and focused to a second focusing point in the laser crystal; a third laser pumping source assembly emits third pumping light; after the third pumping light is reflected through a third pumping source reflectingmirror, the third pumping light is emitted and focused to a third focusing point in the laser crystal; a fourth laser pumping source assembly emits fourth pumping light; after the fourth pumping light is reflected through a fourth pumping source reflecting mirror and emitted through the third pumping source reflecting mirror in sequence, the fourth pumping light is emitted and focused to a fourthfocusing point in the laser crystal. By adopting the end face uniform pumping type solid laser device, the output power of the laser device is improved and the pulse width of laser is reduced while the volume of the solid laser device is reduced.