CN2358613Y - Full solidification single-frequency double frequency laser - Google Patents

Abstract

The utility model relates to a semiconductor laser (LD) pumping single-frequency doubling operating solid laser. An LD light beam shaping system adopts a self-focusing lens, two direct cross cylindrical mirrors and a focusing lens, and the self-focusing lens is utilized to realize best shaping for the LD light beam for the difference of magnification in X and Y directions. The shape of a cavity adopts a four-mirror annular cavity resonator and uses different gain medium Nd with YAG and Nd with YVO4, and a Nd with YAP crystal realizes the single-frequency operation of intracavity frequency multiplication. A laser can reach the highest frequency doubling conversion efficiency and through the utility model stable single-frequency green light output, and the utility model can be used for the technical fields of spectra, coherent communication, laser radars, gravitational wave detection, second-harmonic generation, parameter oscillation, etc.

Description

Full-solidified one-frequency or frequency-multiplying laser device

The utility model relates to a kind of laser, specifically is the continuous solid body laser of a kind of semiconductor laser (LD) pumping one-frequency or frequency-multiplying running.

The eighties is since mid-term, and along with the raising of semiconductor laser practicability level, the solid state laser of diode-end-pumped obtains fast development.Such device not only makes solid state laser really realize full curing, and has the incomparable advantages of other laser such as high efficiency, long-life, compact conformation, frequency stabilization.Domestic and international research department and manufacturer develop the different total solidifying laser device of performance one after another, and occupy a tiny space on laser market rapidly, and the trend that replaces other laser is arranged greatly.Particularly the total solids single frequency laser of semiconductor laser pumping is widely used in spectrum with its excellent characteristic, coherent communication, and laser radar, gravitational wave detection, second harmonic produces, and parametric oscillation reaches fields such as compressed state optical field generation.

The LD of end pumping middle low power mostly adopts the one-dimensional array laser diode, and to 500 μ m, wide is 1 μ m to its luminous face length from 100 μ m, and power output is from five watts of hundreds of milliwatts to four.Its angle of divergence is asymmetric at x, y, and being generally perpendicular to junction plane directional divergence angle is 34 °, and being parallel to junction plane directional divergence angle is 10 °.The LD beam shaping is usually adopted collimation lens and a condenser lens, and asymmetric because of the LD light-emitting area and the angle of divergence makes the pump light size that enters gain media big and be ellipticity, final conversion efficiency that will the whole laser of influence.Asymmetry according to the LD light-emitting area and the angle of divergence, it is right to add a prism beam expander between collimating lens and condenser lens, realize the x of whole orthopedic systems, the multiplication factor that the y direction is different, can reach pumping size preferably, but prism is bigger to difficult adjustment and loss.

The solid state laser of the vertical pumping of end face is easy to realize single transverse mode output, has now adopted several different methods to make this device reach single longitudinal mode running (Dai Teli writes " semiconductor diode pump solid state laser " publishing house of Sichuan University, 1993).For example with reversing die cavity, short cavity resonance utilizes the etalon modeling, and utilization has the laser medium short distance absorptive pumping light of high absorption coefficient etc.But have only the ring resonator of utilization, make the unidirectional running of laser, just can realize accurate modeling, thereby reach desirable frequency stability by in resonant cavity, inserting the optical-unidirectional device.In early days, people design laser diode-pumped monoblock and non-planar ring laser, this design is made in unidirectional belt resonant cavity in the monolithic Nd:YAG laser crystal, except that output coupling mirror, other three reflectings surface utilize inner total reflection, and utilize Nd:YAG crystal itself as faraday rotator.Because the interior cavity loss of this resonant cavity is reduced to minimum, thereby the pumping threshold of laser can reduce to below the 5mW, and the frequency stabilizer pole of this laser.But people find the ring laser of being made up of resolution element gradually its incomparable advantage is also arranged.This laser is easy to constitute, regulate, and can insert various elements in resonant cavity, and laser is turned round by different way.Ring cavity is realized stable single-frequency output, and high conversion efficiency is strict in the design of chamber shape, especially concerning inner cavity frequency-doubling, introduce non-linear loss because of adding frequency-doubling crystal in the chamber, the depolarization loss of polarised light etc. make laser obtain quite difficulty of stable single-frequency green glow output.

The purpose of this utility model is to design a kind of whole conversion efficiency height, the stable full-solidified one-frequency or frequency-multiplying solid state laser of single-frequency operation.

Full-solidified one-frequency or frequency-multiplying laser device provided by the utility model, form by semiconductor laser, pump light orthopedic systems and belt resonant cavity, put into gain medium and frequency-doubling crystal in the chamber, it is characterized in that orthopedic systems is made up of a GRIN Lens, cylindrical mirror and condenser lens, belt resonant cavity is made up of four mirror Eight characters chambeies.

Described orthopedic systems is made up of a GRIN Lens, pairwise orthogonal cylindrical mirror and condenser lens.GRIN Lens is being a convex surface near LD one end, and the other end is the plane.The convex surface of GRIN Lens one end is in order to reduce the spherical aberration of lens, increases to receive optic angle, thereby strengthens the light gathering of GRIN Lens, obtains less focused spot size.The multiplication factor of GRIN Lens with apart from the distance dependent of LD emitting facet, and the protection window of a plating anti-reflection film is arranged before the LD emitting facet, thus the thickness of window and determining positions the multiplication factor of GRIN Lens.There is a convergent point at about 1.3mm place behind the grin rod output end face.For the 4W laser, vertical y direction becomes 6 ° by 34 °, and horizontal x direction becomes 28 °, and therefrom calculating GRIN Lens y direction multiplication factor is 0.18 ^*, x direction 2.3 *.GRIN Lens x, y direction symmetry optical element is realized x, the amplification that the y direction is different, and this uses a prism that expansion Shu Shixian x, amplification that the y direction is different are had play the same tune on different musical instruments wonderful with the orthopedic systems that has.Thereafter the cylindrical mirror that uses two quadratures to place, x, the y direction of LD being exported laser are shaped as approximate directional light respectively, and the condenser lens by footpath at a gulp focuses on pump light at last.

Described belt resonant cavity adopts four mirror ring cavities, is made of two level crossings and two concave mirrors, and light beam can form two waist spots in the chamber like this, can carry out frequency multiplication and pump mode coupling respectively.Two concave mirror curvature are little, form a less waist spot between them, can make ktp crystal reach maximum non-linear conversion efficient.Also have a waist spot between two level crossings, this waist spot and pumping waist spot are complementary and reach best pattern waist spot size.

In the solid state laser of designing semiconductor laser pumping, a most important parameters of decision lasing efficiency and power output is pump beam and the zlasing mode overlapping degree at gain media.Endovenous laser mode sizes after the optimization has determined belt cavity resonator structure size.Nd:YVO ₄The absorption length of crystal is about 1.8mm, and Nd:YAG and Nd:YAP absorption length are slightly long.Should be positioned at through the numerical computations focal plane that to enter crystrallographic plane 1mm place best.4W LD minimum average B configuration waist spot size behind orthopedic systems is 35.4 μ m, and ovality is 0.112.Set out according to limit and first approximation according to having the space variable rate equation, the chamber internal schema waist spot size of the best is 230 μ m when obtaining maximum power output.The last condenser lens focal length of orthopedic systems is 50mm, the focus point of pump light is at distance input mirror 30mm place, therefore the position of adjusting four chamber mirrors overlaps the chamber mould waist spot between two level crossings and the focus point of pump light, and coincide point in gain media apart from front end face 500 μ m～2mm place.The gain media front end face is coated with pump light and infrared pair of anti-reflection film, and the other end is an infrared anti-reflection film.

Under certain inner chamber power condition, frequency-doubling conversion efficiency reduces and increases with the waist spot in the frequency-doubling crystal, when the confocal length of beam waist spot size correspondence during smaller or equal to the length of frequency-doubling crystal, light beam has in crystal to be dispersed significantly and has reduced light intensity, and the walk-off effect of frequency-doubling crystal, all weakened the second harmonic generation, so reasonably situation is the length that the confocal length that focuses of the light beam into the waist spot correspondence of light beam equals frequency-doubling crystal.Under suitable condition, can not that the ripple of ω extracts with frequency for 2 ω with the whole applicable power of laser.Suppose under each given pumping condition, when the outgoing mirror mask has the transmissivity of (the best) 3 percent, power output can reach maximum, having absolutely with one to ω, the minute surface of reflectivity replaces the output minute surface, and in resonant cavity, place a nonlinear crystal, if whenever walking once this moment by ω is 3 percent to the conversion efficiency of 2 ω, this laser just reverts to original such optimum state again, only Yi Qian loss is owing to power is coupled away through the output minute surface, present power loss is because second harmonic produces, thereby the laser power that be coupled away through minute surface before just equaling of the 2 ω power that produce, so just be equivalent to the gross power that laser can supply originally and change to second harmonic fully.The length of choose reasonable frequency-doubling crystal when design, frequency-doubling crystal is placed on the center of the chamber mould waist spot between resonant cavity two concave mirrors that goes in ring, and the confocal length of chamber mould is slightly larger than or equals the length of frequency-doubling crystal.

When pump light exciting laser gain media, a part has produced desirable population inversion number, remaining part, because radiationless transition, the direct absorption of matrix and active population transition that population inversion is not had a contribution are dissipated in the operation material with the form of heat, make operation material produce physical effects such as temperature rise, hot focus and birefringence, but these effect Approximate Equivalent are a positive thermal lens, this has seriously influenced the performance of laser.Can wear into the certain curvature concave surface with the influence of elimination thermal lens at the rod end in order to compensate thermal lens, yet under this method situation that only thermal focal remains unchanged in whole running, TEM ₀₀Mould just can improve, but thermal focal is slightly offset, and beam characteristics just degenerates at once.When chamber shape is designed, adopt the heat insensitive chamber, guarantee that beam divergence angle and mode volume are insensitive for the variation of the evenly heat focal length of laser bar when the shape of certain chamber, the heat insensitive condition is | A+D|=0, A and D are the elements of resonant cavity Ray Matrix.So, when laser chamber shape is designed, can suitably choose parameter, to improve the thermal effect that laser brings owing to pumping.

At YVO ₄Frequency-doubling crystal is selected the ktp crystal by the cutting of II class phase matched direction for use in+KTP the single frequency laser.Nd:YVO ₄Be uniaxial crystal, its parallel and optical axis (being the c axle) Laser emission cross section of direction are perpendicular to 4 times of optical axis direction, and output is the linearly polarized light that is parallel to optical axis.Fast axle and the Nd:YVO of KTP ₄Optical axis angle at 45 (requirement of the phase matched during II class phase matched ktp crystal frequency multiplication).KTP is a biaxial crystal, is placed on to play a wave plate in the chamber, and the temperature that therefore must control ktp crystal makes the effect that it serves as a full-wave plate to first-harmonic, to reduce the loss that ktp crystal is introduced the first-harmonic depolarization.When the design laser resonant cavity, conscientiously choose the inner chamber element and introduce little loss as far as possible, non-linear loss is occupied an leading position.The output of inner cavity frequency-doubling and first-harmonic has very big different in the design of chamber shape.During design fundamental frequency output cavity, because output coupling mirror is constant in wideband section internal transmission factor very, so it is identical aligning the loss of reciprocal light wave introducing, in the chamber, add some element both forward and reverse directions and introduce very little loss difference, just can unidirectional running single-frequency output in the chamber.For example, the loss difference that adds the light wave introducing of an acousto-optic modulator both forward and reverse directions in the chamber is 0.02%, and this enough makes the unidirectional running of light wave in the chamber.But different at inner chamber, find out that from front inner cavity frequency-doubling theory analysis the non-linear loss that frequency multiplication introduces is relevant with fundamental power in the chamber, in the chamber the non-linear loss of the first-harmonic of starting of oscillation direction big, another direction is little, so non-linear loss also is a kind of loss difference.The loss difference of cavity total=isolator is introduced loss difference-non-linear loss difference.In the design of inner cavity frequency-doubling chamber shape, to make isolator introduce loss difference greater than non-linear loss.

Nd:YAP is a biaxial crystal, the Nd:YAP rod that uses for what draw along the b direction of principal axis, for the Nd:YAP crystal bar of b axle orientation, it is the strongest that the polarization direction is parallel to the 1.08 μ m spectral lines gain of c axle, so it and Nd:YVO ₄Crystal is realized the mechanism unanimity of single-frequency operation.

The Nd:YAG crystal is a HOMOGENEOUS BROADENING MEDIUM, in ring laser, make the unidirectional running of laser, eliminate effects of spatial, make laser realize the single longitudinal mode running, in laser, add the optical-unidirectional device usually, do not introduce the loss of forward-propagating laser, and the polarization loss of increase backpropagation laser forces the unidirectional running of laser.Usually the optics isolator is by playing inspection device partially, Faraday rotator, / 2nd wave plates are formed, for the interior cavity loss that reduces laser as far as possible and make laser structure simply compact, we design the belt resonant cavity of four mirror on-plane surfaces, utilize the laser of forward and reverse propagation in the chamber, to propagate the reverse each other polarization direction rotation that produces after the week, replace 1/2nd wave plates, and magnetic field is added on the Nd:YAG laser crystal, utilize the faint Faraday effect of Nd:YAG crystal, make the laser of forward and reverse propagation produce each other in the same way polarization direction rotation, replace usually magnetic field being added in the Faraday rotator that constitutes on the TGG gyrotropi crystal.Can reduce the polarization loss of forward-propagating laser by regulating the on-plane surface angle in the design, increase the polarization loss of backpropagation laser, force the unidirectional running of laser, obtain single-frequency laser output.

The full curing single-frequency solid laser device of the utility model design has been compared following advantage with the single-frequency solid laser device of having reported:

1. it is made up of resolution element, easily constitutes, easily regulates.

2. orthopedic systems is good to the shaping effect of pump beam, can realize optimal spatial overlapping coupling with the chamber mould, improves the conversion efficiency of laser and the zlasing mode that can obtain.

3. the utility model adopts four mirror ring cavities, forms two waist spots in the chamber, and one is carried out pump light and chamber mould maximum space overlapping coupling, and another carries out best frequency-doubled conversion, and the laser pumping threshold value is reduced, and frequency-doubling conversion efficiency improves.

4. considered the heat insensitive condition on the shape of chamber, made laser output more stable.

5. consider the different of inner cavity frequency-doubling and infrared single-frequency operation, conscientiously designed the single-frequency output of inner cavity frequency-doubling, realized long-time stable single-frequency green glow output and mode hopping not.

In a word, the whole conversion efficiency height of this laser, single-frequency operation are stablized.

Brief description of drawings

Fig. 1, the utility model Nd:YVO ₄The structural representation of+KTP (the critical coupling of two classes) one-frequency or frequency-multiplying laser device.

The structural representation of Fig. 2, the utility model Nd:YAG+KTP (the critical coupling of two classes) one-frequency or frequency-multiplying laser device.

The structural representation of Fig. 3, the utility model Nd:YAP+KTP (two class non-critical phase matchings) one-frequency or frequency-multiplying laser device.

Further describe embodiment of the present utility model below in conjunction with accompanying drawing.

Embodiment one Nd:YVO of the present utility model ₄+ KTP (the critical coupling of two classes) single frequency laser, as shown in Figure 1.LD pump beam orthopedic systems by a GRIN Lens 1, pairwise orthogonal cylindrical mirror 2 and 3 and condenser lens 4 form.The numerical aperture .N.A=0.6 of GRIN Lens 1, diameter 1.5mm, long 3mm, grin rod is being a convex surface near LD one end, the other end is the plane.The convex surface of GRIN Lens one end is in order to reduce the spherical aberration of lens, increases to receive optic angle, thereby strengthens the light gathering of GRIN Lens, obtains less focused spot size.Cylindrical mirror 2 is 15 * 10mm, and focal length is 20mm, and cylindrical mirror 3 is 15 * 10mm, and focal length is 40mm, and the cylindrical mirror that uses these two quadratures to place is exported the x of laser with LD, and y is put to being shaped as approximate directional light respectively.Condenser lens 4 apertures are Φ 20mm, and focal length is 50mm, and collimated light beam is focused on apart from the about 30mm of input coupling mirror place.

In the utility model, use 1) LD of SLI-CW 1W, light-emitting area is 100 μ m * 1 μ m, far-field divergence angle θ _//=12 °, θ _=34 °.By measuring the angle of divergence of pump beam, estimate the spot size of pump light in gain media through orthopedic systems.Spot size 6 * the 5mm of collimated light beam before condenser lens becomes θ through the condenser lens pump beam angle of divergence _=2arctg (5/ (50 * 2))=5.7 °, θ _//=2arctg (6/ (50 * 2))=6.9 ° becomes 3.2 ° and 3.8 ° after entering gain media.The vertical direction angle of divergence has been dwindled 6 times, and it is 6 μ m that vertical direction enters the increase of gain media hot spot, and the horizontal direction angle of divergence has been dwindled 1.7 times, and it is 170 μ m that horizontal direction enters the gain media hot spot.2) LD of 2W, light-emitting area is 200 μ m * 1 μ m, far-field divergence angle θ _//=12 °, θ _=34 °.Spot size 6 * the 5mm of collimated light beam before condenser lens becomes θ through the condenser lens pump beam angle of divergence _=5.7 °, θ _//=6.9 °, become 3.2 ° and 3.8 ° after entering gain media.The vertical direction angle of divergence has been dwindled 6 times, and it is 6 μ m that vertical direction enters the increase of gain media hot spot, and the horizontal direction angle of divergence has been dwindled 1.7 times, and it is 340 μ m that horizontal direction enters the gain media hot spot.3) LD of SDL4W, light-emitting area is 500 μ m * 1 μ m, far-field divergence angle θ _//=12 °, θ _=34 °.Spot size 12 * the 3mm of collimated light beam before condenser lens becomes θ through the condenser lens pump beam angle of divergence _=3.4 °, θ _//=13.7 °, become 1.9 ° and 7.7 ° after entering gain media.The vertical direction angle of divergence has been dwindled 10 times, and it is 10 μ m that vertical direction enters the increase of gain media hot spot, and the horizontal direction angle of divergence has been dwindled 1.1 times, and it is 450 μ m that horizontal direction enters the gain media hot spot.

Gain media 9 in the laser adopts the Nd-doped yttrium vanadate (Nd:YVO of A axle cutting ₄) the effective stimulated emission cross section of crystal at 1.064 mum wavelength places be 15.6 * 10 ^-19Cm ²Be the Nd:YAG crystal 4 doubly about.Compare Nd:YVO with the Nd:YAG crystal of the identical Nd of mixing concentration ₄Want high nearly 5 times at the absorption coefficient of 808nm wave band, absorb also broad of bandwidth, YVO ₄Doping content can from 0.1% to 3% and YAG is the highest can only be to 1.5%.So Nd:YVO ₄Crystal has low pumping threshold than the Nd:YAG crystal, high conversion efficiency.Nd:YVO in the example ₄The doping content of crystal is 0.5at-%, and cross section is 3.0 * 3.0 (mm), and a axle leads to light, and optical direction length is 5.0 (mm), and the front surface of crystal plates the two antireflective films of 1.064 μ m/809nm, residual reflectance R _{1.064 μ m}＜0.2%, R _809nm＜5%, 1.064 μ m antireflective films, residual reflectance R are plated in the rear surface _{1.064 μ m}＜0.2%.At the 809nm place, crystal is 21.0cm to the absorption coefficient of the polarized pump light that is parallel to the c axle ^-1, be 10.4cm to the absorption coefficient of the polarized pump light that is parallel to a axle ^-1, so we select the polarized pump that is parallel to the c axle for use.

8 are plane input coupling mirror, to high anti-, the 809nm anti-reflection of 1.064 μ m, R _{1.064 μ m}＞99.5%, R _{809 μ m}＜5%; 13 is the plane output coupling mirror; 5,7 is curved mirror, and 5 couples 1.064 μ m are high anti-, reflectivity R _{1.064 μ m}＞99.5%, 7 couples 1.064 μ m, 0.53 μ m are high anti-, and radius of curvature all is 50mm; Consider the compactedness of laser resonator structure and guarantee pump light and the fine overlapping and laserresonator of oscillating laser can be in steady district, select I ₁=114mm, I ₂=113mm, I ₃=57mm, I ₄=63mm.Under this cavity resonator structure, the stability condition of laserresonator | A+D|=0, can guarantee that like this laser can steady running, even cavity resonator structure changes slightly, also be unlikely making laser be in non-steady district.Need to prove that it is approximate in Gaussian beam more than discussing, and disregards astigmatism, so even select | A+D|=0 is exactly the existence of considering to have above-mentioned influence, and laser also can steady running.Can calculate the laser waist spot radius w between the chamber mirror 8 and 13 equally ₀=226 μ m, the waist spot is 30mm apart from 8 distance.Average pumping waist spot radius is 240 μ m, just can guarantee substantially that under this cavity resonator structure pump light and oscillating laser are fine overlapping, pump light can only excite fundamental transverse mode like this, makes laser be in the fundamental transverse mode running, improves energy conversion efficiency simultaneously to greatest extent.Can determine the insertion position of laser crystal by the position of waist spot.Waist spot radius between the chamber mirror 5 and 7 is 29 μ m, and confocal length is 5mm, just in time is the length of ktp crystal.The waist spot is in the centre of two mirrors, also in the centre of ktp crystal.

At design Nd:YVO ₄During+KTP ring cavity, utilize Nd:YVO ₄The excitation cross-section of crystal c axle (optical axis) direction is 4 times of a axle, suppose that the excitation cross-section is linear change from the c axle to a axle, the terbium gallium garnet TGG of Φ 3 * 5 (mm) in the chamber (Terbium Gallium Garnet) crystal 10 adds Φ 15 * 15 (mm) permanent magnet 11, magnetic field intensity is 5000 Gausses, can produce 5 ° polarization rotation to 1.064 μ m, introducing the both forward and reverse directions loss difference so is 8.3%, and this is enough to keep unidirectional running in the chamber.12 is 1/2nd wave plates, and both sides all are coated with the anti-reflection film of 1.064 μ m.This laser maximum can get the single-frequency green glow and be output as 200mW, and long-term stability is output as 150mW.

Single frequency laser as shown in Figure 2 for embodiment two Nd:YAP+KTP of the present utility model (two class non-critical phase matchings).The pump light orthopedic systems is with embodiment one.Gain media 9 Nd:YAP crystal are biaxial crystal, and we use the YAP rod for what draw along the b direction of principal axis, and for the Nd:YAP crystal bar of b axle orientation, output light is the laser that the polarization direction is parallel to 1.08 μ m of c axle.Cavity shape structure is with embodiment one.But frequency-doubling crystal 6 adopts the ktp crystal of two class non-critical phase matchings, can reach 0.01 ° heating furnace 14 by a temperature-controlled precision and crystal is heated to 63 ° reaches the temperature coupling.Because of crystal is that the temperature coupling has less walk-off effect, adopt the ktp crystal of 3 * 3 * 10mm in the example, both sides all are coated with the anti-reflection film of 1.08 μ m.This example obtains 0.54 stable μ m single-frequency green glow and is output as 80mW.

Single frequency laser as shown in Figure 3 for embodiment three Nd:YAG+KTP of the present utility model (the critical coupling of two classes).The pump light orthopedic systems is with embodiment one.5,7 is curved mirror, and 5 couples 1.064 μ m are high anti-, reflectivity R _{1.064 μ m}＞99.5%, 7 couples 1.064 μ m, 0.53 μ m are high anti-, reflectivity R _{1.064 μ m}＞99.5%, radius of curvature is 40mm, 50mm respectively; By regulating four chamber mirrors, make the on-plane surface angle of resonant cavity be about 1.5 °; Gain media 9 is the Nd:YAG crystal, is of a size of φ 3 * 10mm, and front surface plates the two antireflective films of 1.064 μ m/809nm, residual reflectance R _{1.064 μ m}＜0.2%, R _809nm＜5%, 1.064 μ m antireflective films, residual reflectance R are plated in the rear surface _{1.064 μ m}＜0.2%, crystal places M ₁, M ₂Between waist spot place.Chamber shape is selected I ₁=120mm, I ₂=100mm, I ₃=49mm, I ₄=80mm.Under this cavity resonator structure, the stability condition of laserresonator | A+D|=0.Laser waist spot radius w between the chamber mirror 8 and 13 ₀=205 μ m, the waist spot apart from 8 apart from 32mm.Waist spot radius between the chamber mirror 5 and 7 is 26 μ m, and the waist spot is 22mm apart from 5 distance.

In resonant cavity, insert the higher vitreous silica thin slice 15 of optical quality, and press the Brewster angular range and place, utilize light beam vertical polarization component to exist certain reflectivity that this direction loss is increased, vertical polarization can not form laser in resonant cavity, the reflectivity of horizontal polarization component is zero, guarantees that this direction resonance amplifies.Making the laser by resonant cavity output is the very high linearly polarized light of purity, and the Brewster angle is 55 °.Magnetic field directly is added on the Nd:YAG laser crystal, utilizes the Faraday effect of Nd:YAG crystal, make the laser of forward and reverse propagation produce each other in the same way plane of polarization and rotate and constitute Faraday rotator.When optical maser wavelength was 1.06 μ m, the Verdet constant of Nd:YAG crystal was V=105 ° of T ^-1m ^-1As Nd:YAG crystal length 1=10mm, when being added in the magnetic field intensity B=5000 Gauss on the Nd:YAG crystal, laser is ψ=VIB=0.6 ° through the angle of Nd:YAG crystal rear polarizer face rotation.Rotation oppositely with adding magnetic direction relevant, to note the direction in the excellent insertion of the YAG magnet in the design.By regulating on-plane surface angle Ω, make the unidirectional running of laser, and the orientation of adjusting Brewster window and Nd:YAG crystal makes laser reach optimum state.This example obtains 0.53 stable μ m single-frequency green glow and is output as 80mW.

Claims (9)

1. full-solidified one-frequency or frequency-multiplying laser device, form by semiconductor laser, pump light orthopedic systems and belt resonant cavity, put into gain medium (9) and frequency-doubling crystal (6) in the chamber, it is characterized in that orthopedic systems is made up of a GRIN Lens (1), cylindrical mirror (2) (3) and condenser lens (4), belt resonant cavity is made up of four mirror Eight characters chambeies.

2. full-solidified one-frequency or frequency-multiplying laser device according to claim 1, the GRIN Lens (1) that it is characterized in that orthopedic systems is that an end is a convex surface, the other end is the plane, and cylindrical mirror (2) (3) is the cylindrical mirror that two quadratures are placed, and condenser lens (4) is a bigbore planoconvex spotlight.

3. full-solidified one-frequency or frequency-multiplying laser device according to claim 1, the resonant cavity that it is characterized in that going in ring is made up of four chamber mirrors, two chamber mirrors (5) (7) are concave mirror, two chamber mirrors (8) (13) are level crossing, gain media (9) is placed between two level crossings (8) (13), and frequency-doubling crystal (6) is between two concave mirrors (5) (7).

4. full-solidified one-frequency or frequency-multiplying laser device according to claim 3, it is characterized in that going in ring the chamber mould waist spot between resonant cavity two level crossings (8) (13) and the focus point of pump light overlaps, and coincide point in gain media (9) apart from front end face 500 μ m～2mm place, gain media (9) front end face is coated with pump light and infrared pair of anti-reflection film, and the other end is an infrared anti-reflection film.

5. full-solidified one-frequency or frequency-multiplying laser device according to claim 3 is characterized in that belt resonant cavity frequency-doubling crystal (6) is placed on the center of the chamber mould waist spot between two concave mirrors (5) (7), and the confocal length of chamber mould is slightly larger than or equals the length of frequency-doubling crystal.

6. full-solidified one-frequency or frequency-multiplying laser device according to claim 3 is characterized in that making the stability condition of resonant cavity | A+D|=0.

7. according to the described full-solidified one-frequency or frequency-multiplying laser device of arbitrary claim in the claim 2 to 6, gain media (9) adopts Nd:YVO in the resonant cavity that it is characterized in that going in ring ₄Crystal, frequency-doubling crystal (6) are the KTP of two class angles coupling, also put into the light isolator of being made up of the TGG crystal (10) and 1/2nd wave plates (12) of externally-applied magnetic field (11) in the chamber, make the output of frequency multiplication green glow single-frequency.

8. according to the described full-solidified one-frequency or frequency-multiplying laser device of arbitrary claim in the claim 2 to 6, it is characterized in that gain media (9) adopts the Nd:YAP crystal in the belt resonant cavity, frequency-doubling crystal (6) is the KTP of two class temperature coupling, also put into the light isolator of forming by the TGG crystal (10) and 1/2nd wave plates (12) of externally-applied magnetic field (11) in the chamber, make the output of frequency multiplication green glow single-frequency.

9. according to the described full-solidified one-frequency or frequency-multiplying laser device of arbitrary claim in the claim 2 to 6, it is characterized in that gain media (9) adopts the Nd:YAG crystal in the belt resonant cavity, frequency-doubling crystal (6) is the KTP of two class angles coupling, the Nd:YAG crystal adds magnetic field (11), the light isolator is formed in the Faraday effect of Nd:YAG crystal itself and on-plane surface chamber, makes the output of frequency multiplication green glow single-frequency.

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