CN101752773A - Laser head - Google Patents
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- CN101752773A CN101752773A CN200810239243A CN200810239243A CN101752773A CN 101752773 A CN101752773 A CN 101752773A CN 200810239243 A CN200810239243 A CN 200810239243A CN 200810239243 A CN200810239243 A CN 200810239243A CN 101752773 A CN101752773 A CN 101752773A
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Abstract
The invention relates to a laser head, comprising: a pumping source for emitting a continuous laser; a light-splitting device for splitting the continuous laser generated by the pumping source to two pulse-type pumping lasers; and two laser resonant cavities respectively for receiving the two pulse-type pumping lasers and alternatively outputting the pulse-type lasers. The laser head, which can radiate sufficiently, can reduce laser crystal thermal gradient and diminish thermal effect to the maximal extent in relation to continuous lasers, thereby enhancing photoelectric conversion efficiency and total output power of laser; two laser resonant cavities according to the invention are relatively complemented in time in the aspect of laser output, and relative to pulse-modulated lasers, the device according to the invention enhances the time utilization rate of the pumping source; and the device is low in cost, simple in operation and advantageous in large-scale production.
Description
Technical field
The invention belongs to field of lasers, relate in particular to a kind of laser head that is used for solid state laser.
Background technology
Solid state laser can produce the thermal effect phenomenon in the course of work, and thermal effect comprises thermal lensing effect, thermic stress birfringence effect and hot fevering sodium effect.The generation of thermal effect can influence the output energy and the job stability of laser, comprise specifically following some:
1, temperature can raise after laser crystal absorbed heat in the process of optical pumping, and the thermal stress of corresponding laser crystal is directly proportional with pump energy, and when the pump energy increase, when the maximum stress in the laser crystal surpasses the material damage limit, laser crystal will rupture;
2, the thermal stress that produces in laser crystal can cause change of refractive, makes original isotropic medium become anisotropy, thermic stress birfringence effect that Here it is;
3, face deformation also can take place in laser crystal in the process of optical pumping, thermal lensing effect that Here it is.
The thermal effect of solid state laser has seriously hindered the further raising of laser delivery efficiency, and beam quality is reduced, and should take measures necessary to suppress in practice or reduces thermal effect.The measure of several compensation opticaly-pumpedsolidlaser thermal effects commonly used is arranged usually, comprise cooling, optical filtering and optical compensation method etc.And the continuous wave laser of the cooling means of employing routine, its thermal effect has obtained reducing to a certain degree, but because the continuous pumping of pump light is to laser crystal, heat can not get discharging timely, thermal effect strengthens, and heat accumulates in laser crystal and causes high thermal gradient, and problems such as thermal effect or thermic stress birfringence effect can take place, make laser crystal inhomogeneous, cause its light light conversion efficiency low low with electro-optical efficiency to the absorption of pump light.And for being subjected to pulse modulated laser, though the heat that its pump light accumulates in laser crystal can obtain release to a certain degree in the laser output gap, but, the time availability of the pumping source of whole laser device is low, promptly do not had under the situation of laser output by pulse modulated laser, the electric energy of pumping source is depleted, and has reduced the electro-optical efficiency of system.In sum, conventional solid state laser or because crystal thermal effect and electro-optical efficiency is low or the time availability of pumping source is low in a word, is difficult to reach the purpose that both realize simultaneously.
Summary of the invention
The invention provides a kind of can realize simultaneously effectively reducing thermal effect and the laser head that improves the pumping source time availability.In addition, the present invention also provides a kind of laser display light source that utilizes above-mentioned laser head to make.
To achieve these goals, the invention provides a kind of laser head, comprising: pumping source is used for emission and produces continuous laser; Light-dividing device is used for the continuous laser that described pumping source produces is divided into two beam pulse formula pumping lasers; And
Two laserresonators are respectively applied for the described two beam pulse formula pumping lasers of reception and alternately export pulse laser.
In the technique scheme, described pulsed pumping laser is a recurrent pulses laser.
In the technique scheme, described pulsed pumping laser is the pulse laser of square wave form.
In the technique scheme, the duty ratio sum of described two beam pulse formula pumping lasers is that 100%, two beam pulse formula pumping laser alternately produces, and wherein arbitrarily the duty ratio of beam of laser all in 25% to 75% scope.
In the technique scheme, described light-dividing device comprises polarised light conversion element and light splitting device.
In the technique scheme, described polarised light conversion element is electrooptic crystal or Faraday polarization apparatus.
In the technique scheme, the frequency of described pulsed pumping laser is that 50Hz is to 2KHz.
In the technique scheme, comprise separately all in two described laserresonators that a laser crystal or two described laserresonators comprise a shared laser crystal.
In the technique scheme, comprise separately also in two described laserresonators that an outgoing mirror or two described laserresonators comprise a shared outgoing mirror.
In the technique scheme, comprise separately also in two described laserresonators that a frequency-doubling crystal or two described laserresonators comprise a shared frequency-doubling crystal.
In the technique scheme, all place a coupled lens before two described laserresonators separately.
In the technique scheme, described laser head also comprises the speculum that is used to adjust optical path direction.
In the technique scheme, described laser head also comprises and closes the bundle output device, is used for that bundle is closed in the output of described two laserresonators and handles.
In the technique scheme, described to close the bundle output device be light combination mirror, is used for that bundle is closed in the output of two laserresonators and handle obtains continuous laser output; The output frequency difference of described two laserresonators.
The present invention also provides a kind of laser display light source, comprises light source group, coupled lens group and fiber bundle, it is characterized in that, described light source group is made up of at least one above-mentioned described laser head;
Coupled lens in the described coupled lens group is one by one corresponding to the output beam of described laser head, be used for the output beam of described laser head respectively shaping be coupled in the corresponding optical fiber of described fiber bundle.
In the technique scheme, the quantity of the coupled lens of described coupled lens group is the twice of the quantity of described laser head, and the number of fibers of described fiber bundle equates with the quantity of the coupled lens of described coupled lens group.
In the technique scheme, the output of described optical fiber is fixed as a branch of with fixture.
Adopt technique scheme, have following beneficial effect:
Compare with continuous wave laser, two laser crystals of the present invention can dispel the heat better, can reduce the laser crystal thermal gradient better and reduce thermal effect.Further,, can improve the light light conversion efficiency of single channel laser significantly, thereby improve the electro-optical efficiency of single unit system, also improve the laser output gross power of single unit system simultaneously by power supply being adjusted in the preferred duty cycle range.In addition, the output of the laser of two laserresonators among the present invention is complementary in time, makes whole device that laser output all be arranged any time, and therefore with respect to being subjected to pulse modulated laser, the present invention has improved the time availability of pumping source.In addition, apparatus of the present invention cost is low, and is simple to operate, is beneficial to large-scale production.
Description of drawings
Fig. 1 is the structural representation of a kind of polarization spectro laser head of embodiments of the invention one;
Fig. 2 is among the embodiment one of laser head of the present invention, s polarisation component in the incident pump light and p polarisation component were respectively 100%: 0 o'clock, and the percentage that is applied to voltage signal on the electrooptic crystal, accounts for gross power through the s polarisation component in the emergent light of electrooptic crystal and p polarisation component, the power output of two laser crystals concern schematic diagram over time;
Fig. 3 is s polarisation light path light light conversion efficiency figure among the embodiment one;
Fig. 4 is the structural representation of a kind of polarization spectro laser head of embodiments of the invention two;
Fig. 5 is among the embodiment two of laser head of the present invention, s polarisation component in the incident pump light and p polarisation component were respectively 80%: 20% o'clock, and the power output that be applied to voltage signal on the electrooptic crystal, accounts for the percentage of gross power, two laser crystals through the s polarisation component in the emergent light of electrooptic crystal and p polarisation component is schematic diagram over time;
Fig. 6 is the structural representation of the laser display light source of the embodiment of the invention three.
Embodiment
The present invention will be further described below in conjunction with the drawings and specific embodiments.
Embodiment one:
Fig. 1 shows the structural representation of a kind of polarization spectro laser head of present embodiment.As shown in Figure 1, laser head comprises pumping source 112, polarised light conversion element 101, light splitting device 102, first coupled lens 103 and second coupled lens, 113, the first laser crystals 105 and second laser crystal 115, speculum 108, first frequency-doubling crystal 107 and second frequency-doubling crystal, 117, the first outgoing mirrors 106 and second outgoing mirror 116.First laser crystal, 105 place light paths are defined as first light path, and second laser crystal, 115 place light paths are second light path.The polarised light that pumping source 112 generates is as the pump light of first light path and second light path.Polarised light conversion element 101 is used for s polarised light and p polarised light are changed, and when meeting certain condition, becomes the p polarisation during s polarisation outgoing that enters polarised light conversion element 101, becomes the s polarisation during p polarisation outgoing that enters polarised light conversion element 101; When meeting another condition, polarised light conversion element 101 is inoperative.Light splitting device 102 is used for the s polarisation is separated from the space with the p polarisation, obtains the two-way pump light, and the two-way pump light incides first light path and second light path respectively.
In the present embodiment, polarised light conversion element 101 adopts electrooptic crystal.When this electrooptic crystal voltage is got
The time (V
πBe half-wave voltage), the phasic difference that light beam produces is
It is the rotation that 90 degree take place plane of polarization.The low level that the one-period square wave voltage signal is set is V
0(V
0＜V
M), high level is
The above-mentioned cycle square wave voltage signal that will have certain duty ratio is applied on the electrooptic crystal, so at low level V
0Driving under, polarised light that pumping source 112 sends does not rotate through electrooptic crystal rear polarizer face, at high level V
MDriving under, polarised light revolves through electrooptic crystal rear polarizer face and turn 90 degrees, and becomes the p polarisation during s polarisation outgoing that promptly enters electrooptic crystal, becomes the s polarisation during p polarisation outgoing that enters electrooptic crystal.Polarised light incides light splitting device 102 through behind the electrooptic crystal, light splitting device 102 is separated the s polarisation with the p polarisation, the s polarisation that separates from light splitting device 102 incides first coupled lens 103, the p polarisation that separates from light splitting device 102 incides second coupled lens 113 after speculum 108 reflections, s polarisation and p polarisation are coupled to first laser crystal 105 and second laser crystal 115 by first coupled lens 103 and second coupled lens 113 respectively, and successively respectively by corresponding frequency-doubling crystal and outgoing mirror.The plane of incidence of first coupled lens 103 and second coupled lens 113 and exit facet all are coated with the anti-reflection film of 808nm.The plane of incidence of first laser crystal 105 is coated with the anti-reflection film and the fundamental frequency reflection of light film of pump light, and the exit facet of first laser crystal 105 is coated with the anti-reflection film of fundamental frequency light; The plane of incidence of first frequency-doubling crystal 107 is coated with the anti-reflection film of fundamental frequency light and the reflectance coating of frequency doubled light, and its exit facet is coated with the anti-reflection film of fundamental frequency light and frequency doubled light; First outgoing mirror, 106 planes of incidence are coated with the anti-reflection film of fundamental frequency reflection of light film and frequency doubled light, and exit facet is coated with the anti-reflection film of frequency doubled light; The plane of incidence of the plane of incidence of first laser crystal 105 and first outgoing mirror 106 constitutes laserresonator; In like manner, second laser crystal 115, second frequency-doubling crystal 117 and second outgoing mirror 116 of second light path plated film with first laser crystal 105, first frequency-doubling crystal 107 and first outgoing mirror 106 of first light path respectively is identical, and speculum 108 is coated with the reflectance coating of pump light.First laser crystal 105 and second laser crystal 115 are subjected to s polarisation and the excitation of p polarisation respectively, and output fundamental frequency light, fundamental frequency light obtain frequency doubled light output by first frequency-doubling crystal 107 and second frequency-doubling crystal 117 respectively.
Specify the course of work of the laser head in this example below, with the ratio of s polarisation component in the pump light and p polarisation component be 100%: 0 be that example describes:
Polarised light conversion element 101 adopts KTP (KTP) electrooptic crystal, pumping source 112 adopts and produces centre wavelength is the GaAs semiconductor laser of 808nm laser, light splitting device 102 is PBS prism (Polarization Beam Splitter, polarization splitting prism), first laser crystal 105 and second laser crystal 115 are Nd-doped yttrium vanadate (Nd:YVO
4) crystal, first frequency-doubling crystal 107 and second frequency-doubling crystal 117 are lbo crystal, are coated with corresponding rete on each crystal.The GaAs semiconductor laser produces linearly polarized light, incides the s polarisation component of pump light of KTP electrooptic crystal and the power percentage of p polarisation component and is respectively 100% and 0, and promptly pump light has only the s polarisation.After the KTP electrooptic crystal carries out polarization conversion, via the PBS prism light is divided into s polarisation component and p polarisation component again, s polarisation component and p polarisation component difference end pumping are in the fundamental frequency light of first laser crystal 105 and second laser crystal 115 and difference outgoing 1064nm, the fundamental frequency light of first light path and second light path respectively through first frequency-doubling crystal 107 and second frequency-doubling crystal 117, is exported the frequency doubled light of 532nm respectively again.As shown in Figure 2, a of Fig. 2 has partly shown the voltage signal that is added on the KTP electrooptic crystal, and this voltage signal is the periodic signal of square wave with the duty ratio of preestablishing, and high level is V
M, low level is V
0, in each cycle of cycle square wave voltage signal, high level lasting time is T
1, low duration is T
2, duty ratio is 25% in the present embodiment, promptly
Be not difficult to draw, under the driving of above-mentioned voltage signal, s polarisation component in the emergent light of KTP electrooptic crystal accounts for total pump luminous power percent profile figure shown in the b part of Fig. 2, and the schematic diagram of p polarisation component is shown in the c part of Fig. 2, and the voltage that wherein is applied on the KTP electrooptic crystal is V
MTime period in, revolve through the linear polarization polarization surface of KTP electrooptic crystal and to turn 90 degrees, revolve and turn 90 degrees so incide the plane of polarization of the s polarisation of KTP electrooptic crystal in this time, be converted to p polarisation (having only p polarisation component) from the light of KTP electrooptic crystal outgoing; The voltage that is applied on the KTP electrooptic crystal is V
0Time period in, linear polarization polarization surface through the KTP electrooptic crystal does not rotate, the plane of polarization rotation does not take place in the s polarisation that incides the KTP electrooptic crystal in this time period, do not change from the light of KTP electrooptic crystal outgoing, still be s polarisation (having only s polarisation component), the duty ratio of the output light of KTP electrooptic crystal is corresponding with the duty ratio of square wave voltage signal like this, wherein the power of s polarisation component in the output light of KTP electrooptic crystal and p polarisation component accounts for the interlaced in time distribution of percentage of total pump luminous power, the power percentage that is s polarisation component is maximum (corresponding present embodiment, be 100%) time, the power percentage of p polarisation component is minimum value (corresponding present embodiment, be 0), otherwise when the power percentage of s polarisation component was minimum value, the power percentage of p polarisation component was maximum.When the ratio of s polarisation component in the pump light and p polarisation component was 100% and 0, then the KTP electrooptic crystal replaced outgoing s polarisation and p polarisation.
In the present embodiment, the PBS prism of light splitting device 102 can be separated into two-way light with s polarisation component from the light of KTP electrooptic crystal outgoing and p polarisation component from the space, therefore for present embodiment, s polarisation that separates by the PBS prism and the distribution in time of p polarisation also respectively as the c of the b part of Fig. 2 and Fig. 2 partly shown in, be the s polarisation and be alternately distributed mutually on the p polarisation time, and duty ratio is corresponding with the signal of telecommunication on being applied to the KTP electrooptic crystal.For present embodiment, under the perfect condition, incide on first laser crystal 105 the s polarisation with incide second laser crystal 115 on the b part of the distribution in time of p polarisation and Fig. 2 and the c of Fig. 2 partly show the same.First light path is at the laser of output 532nm under the excitation of s polarisation, second light path is exported 532nm under the excitation of p polarisation laser, the Output optical power of being not difficult to draw first light path and second light path is distribution schematic diagram in time, as the e of the d part of Fig. 2 and Fig. 2 partly shown in.This shows that for first light path s polarisation of pump light is the cycle square-wave pulse of 75% duty ratio, first light path is subjected to the excitation of s polarisation, exports the pulse laser of 75% duty ratio, in the interval between each pulse output, and the Nd:YVO in first light path
4Crystal can shed the heat of just exporting the laser generation effectively; Equally with s polarisation time of above-mentioned pump light under the interlaced p polarisation excitation, second light path is exported the pulse laser of 25% duty ratio, the Nd:YVO in same principle second light path
4Crystal also can will be exported the laser generation effectively in the interval of pulse output heat sheds, and has reduced the thermal effect of laser crystal preferably, has reduced the thermal gradient of laser crystal, makes the uniform absorption of laser crystal to pump light, has improved Output optical power; Thereby the thermal effect that reduces laser crystal that reached this device improves the electro-optical efficiency of whole device and reaches the purpose of the time availability that improves whole device pumping source simultaneously.Particularly point out, laser crystal in the present embodiment in first light path and second light path and frequency-doubling crystal adopt identical crystal, in other cases, certainly can also select to adopt different laser crystals and/or different frequency-doubling crystals, can export the laser of identical or different wavelength this moment from two light paths respectively, if two-way light path output different wavelength of laser can also be with synthetic one tunnel output of two-way laser.
In addition, the plated film mode of laser crystal, frequency-doubling crystal and outgoing mirror can suitably be adjusted as required in the present embodiment.In addition, the light path in the present embodiment includes frequency-doubling crystal, is frequency doubled light output, also can remove frequency-doubling crystal output fundamental frequency light.Adopt outgoing mirror in the present embodiment, also can remove outgoing mirror, the plated film that is used on the corresponding crystal is realized resonant cavity.Certainly, the plated film of each optical element is according to specifically light path is and different in the light path, and this it will be appreciated by those skilled in the art that.
In addition, in the foregoing description of present embodiment, the pump light that pumping source generates is the s polarisation, but understand easily, the pump light that pumping source generates also can be the p polarisation, when semiconductor laser not during line of departure polarised light, can adopt polarisation element etc. to make semiconductor laser line of departure polarised light earlier.And pumping source can also adopt the solid state laser that is formed by the gain media with birefringent characteristic, for example neodymium-doped yttrium-fluoride lithium (Nd:YLF) solid state laser and neodymium-doped yttrium aluminate (Nd:YAP) solid state laser etc. except that adopting semiconductor laser.
Figure 3 shows that the light light conversion efficiency figure that first light path (s polarisation light path) of embodiment one is obtained under different duty, the first light path light light conversion efficiency is the ratio of the pumping light power of the Output optical power of first light path and first light path.In experiment, the total pump power power of s polarisation and p polarisation (be and) is taken as 4W, and electrooptic crystal is the KTP electrooptic crystal, and laser crystal is Nd:YVO
4Crystal, frequency-doubling crystal are three lithium borates (LBO) crystal, and outgoing mirror is the plano-concave mirror, and two light paths are all exported the 532nm frequency doubled light.Fig. 3 has provided 50Hz in the 2KHz frequency range, and duty ratio is continuous light from 20% change curve that is increased to 100% light light conversion efficiency gradually when duty ratio is 100%.As seen from Figure 3, the light light conversion efficiency of continuous light is less than 5%, and when frequency when 50Hz is in 1KHz, duty ratio surpasses the light light conversion efficiency of 25% square wave all more than or equal to 5%, promptly this moment first light path the light light conversion efficiency all be higher than the light light conversion efficiency of continuous light, because the output of the laser of first light path and second light path is complementary in time, so can infer, duty ratio 25% in 75% and frequency when 50Hz is in 1KHz, the light light conversion efficiency of first light path and second light path is all more than or equal to 5%, so, after this moment, two light path Output optical power merged, the inevitable light light conversion efficiency that also is higher than continuous light of its light light conversion efficiency can obtain higher Output optical power.When duty ratio is 50%～75%, the light light conversion efficiency obviously improves, especially duty ratio was got 60%～70% o'clock, the light light conversion efficiency reaches between peak region, generally can reach more than 9%, at this moment, under the prerequisite that total pump luminous power (be the s polarisation with the power of p polarisation and) equates, even the present invention only considers a road of s polarisation, its Output optical power also can reach 4W * 60% * 9%=0.324W, the Output optical power of exporting light continuously then is 4W * 5%=0.2W, therefore one tunnel optical output power of first light path has surpassed the power output of continuous light, therefore behind first light path of the present invention and second light path output combiner, then can obtain bigger power output.
Pump light can not be a linearly polarized light also, as long as the s polarisation component of this pump light and the power percentage of p polarisation component differ more than 40%, and duty ratio satisfies certain ratio, can realize also that system's electro-optical efficiency height, system time utilance are high and reduce the purpose of laser crystal thermal effect, be that example is described in detail with embodiment two below.
Embodiment two:
Fig. 4 shows the structural representation of the laser head of present embodiment.As shown in Figure 4, laser head comprises pumping source 412, polarised light conversion element 401, light splitting device 402, first coupled lens 403 and second coupled lens, 413, the first laser crystals 405 and second laser crystal, 415, the first outgoing mirrors 406 and second outgoing mirror 416, first speculum 408 and second speculum 407, light combination mirror 404.First laser crystal, 405 place light paths are defined as first light path, and second laser crystal, 415 place light paths are second light path, and light combination mirror 404 planes of incidence and exit facet are coated with the anti-reflection film of first light path output light and second light path output reflection of light film.Polarised light conversion element 401 adopts the KTP electrooptic crystal, and pumping source 412 is the GaAs semiconductor laser of 808nm laser for emission center wavelength, and light splitting device 402 is PBS prism (Polarization Beam Splitter, a polarization splitting prism).The plane of incidence of first coupled lens 403 and second coupled lens 413 and exit facet all are coated with the anti-reflection film of 808nm; First laser crystal 405 is neodymium-doped vanadic acid gadolinium (Nd:GdVO
4) crystal, its plane of incidence is coated with the reflectance coating of 1341nm and the anti-reflection film of 808nm, and its exit facet is coated with the anti-reflection film of 1341nm; The plane of incidence of first outgoing mirror 406 is coated with the reflectance coating of 1341nm; Second laser crystal 415 is neodymium-doped yttrium-aluminum garnet (Nd:YAG) crystal, and the Nd:YAG crystal plane of incidence is coated with the reflectance coating of 1064nm and the anti-reflection film of 808nm, and its exit facet is coated with the anti-reflection film of 1064nm; The part that the plane of incidence of second outgoing mirror 416 is coated with 1064nm sees through film; First speculum 408 is coated with the reflectance coating of 808nm; Second speculum 407 is coated with the reflectance coating of 1064nm.Especially, laser head in the present embodiment also is provided with light combination mirror 404, the plane of incidence of light combination mirror 404 and exit facet all are coated with the anti-reflection film of 1341nm and the reflectance coating of 1064nm, by utilizing light combination mirror 404 that the output of first light path and second light path is swashed the combiner utilization, pulse laser is changed into continuously or quasi-continuous lasing output like this.
Semiconductor laser radiating portion polarised light is as pump light, incide the s polarisation component of pump light of KTP electrooptic crystal and the power of p polarisation component and be respectively 80% and 20%, as shown in Figure 5, the a of Fig. 5 has shown that partly duty ratio is 40% square-wave signal, when the high level VM of square-wave signal is applied on the KTP electrooptic crystal, inciding polarization polarization surface on the KTP electrooptic crystal revolves and turn 90 degrees, so the percentage of s polarisation component from KTP electrooptic crystal emergent light and p polarisation component exchanges, promptly s polarisation component becomes 20% and p polarisation component becomes 80%; When the low level V0 of square-wave signal is applied on the KTP electrooptic crystal, polarization polarization surface through the KTP electrooptic crystal does not rotate, identical from the polarized state of light of KTP electrooptic crystal outgoing with the polarization of incident light state, as seen, under the driving of above-mentioned voltage signal, for present embodiment, s polarisation component in the emergent light of KTP electrooptic crystal and p polarisation component account for total output light power percentage the time distribution situation respectively as the c of the b of Fig. 5 part and Fig. 5 partly shown in.As a whole, the minimum value of corresponding p polarisation when output light is exactly s polarisation component maximum, the s polarisation is the maximum of hour corresponding p polarisation, and the maximum of s polarisation and p polarisation and minimum value are corresponding with the duty ratio of square wave voltage signal on being applied to the KTP electrooptic crystal.
Similar with embodiment one, the PBS prism can be separated into the light from the outgoing of KTP electrooptic crystal s polarisation component and p polarisation component.Therefore the s polarisation that separates by the PBS prism and the distribution in time of p polarisation respectively with the c of the b part of Fig. 5 and Fig. 5 partly show the same, it is the interlaced in time distribution of percentage that the power of p polarisation and s polarisation accounts for total luminous power, and p polarisation duty ratio is identical with the signal of telecommunication on being applied to the KTP electrooptic crystal, is 40%; S polarisation duty ratio is additional mutually with the signal of telecommunication on being applied to electrooptic crystal, is 60%.
Equally, similar with embodiment one, incide Nd:GdVO from the two-way partial poolarized light of PBS prism outgoing
4Crystal is consistent with s polarisation on the Nd:YAG crystal with isolated s polarisation of distribution in time of p polarisation and PBS prism and the distribution in time of p polarisation, and with the c of the b part of Fig. 5 and Fig. 5 partly show consistent.Under the excitation of incident s polarisation and p polarisation, first light path and second light path are exported the laser corresponding with the incident polarisation respectively like this, the Output optical power of first light path and second light path distribute in time respectively as the e of the d part of Fig. 5 and Fig. 5 partly shown in.
Especially, Nd:GdVO in light path
4The rear of crystal and Nd:YAG crystal can also be provided with a light combination mirror 404, is used for the sharp combiner with the output of first and second light paths, and two-way laser is utilized simultaneously, obtains continuous light output under the perfect condition.The optical element of adjusting direction of beam propagation also can be set between first light path, second light path and the light combination mirror 404 simultaneously, between second light path and light combination mirror 404, be provided with second speculum 407 in the present embodiment.
This shows that different with embodiment one is: in the present embodiment, Nd:GdVO
4Crystal and Nd:YAG crystal are subjected to the excitation of pump light always, and this excitation has maximum excitation value and non-vanishing minimum excitation value.Under the pumping of minimum excitation value, Nd:GdVO
4Crystal and Nd:YAG crystal can both carry out the heat that just output laser produces under maximum excitation value excitation situation release to a certain degree, so just reduced heat accumulation to a certain extent, thereby improved the gross power of output laser, and because Nd:GdVO
4The power waveform of the laser of crystal and the output of Nd:YAG crystal is complementary in time, so under the perfect condition, all the time all at output laser, improved the time availability of pumping source for whole system thus.Certainly, one of ordinary skill in the art will appreciate that, also can be in the present embodiment without the light combination mirror 404 and second speculum 407, this moment, laser head obtained the output of two-way light, and, can export the identical laser beam of two-way wavelength equally if the laser crystal of two-way is identical.
Particularly point out, the waveform shown in Fig. 2 and Fig. 5 is a schematic diagram all, can have certain error in the real work.
Utilization is divided into the scheme that two bundle square waves encourage with pump light, can reduce the thermal accumlation of laser crystal, reduces the laser crystal thermal gradient, has reduced the thermal effect of laser crystal effectively, thereby has improved the light light conversion efficiency of whole device greatly.Especially, the duty ratio of the modulation signal that electrooptic crystal adds in the device is in 25% to 75% scope the time, the light light conversion efficiency of two-way all obviously improves than the conversion efficiency of continuous light, and adopt this scheme can reduce the laser crystal thermal effect effectively, so the purpose that the present invention has realized improving the electro-optical efficiency of device simultaneously and improved the pumping source time availability.
Embodiment three:
Laser head of the present invention is applied in effectively eliminate laser speckle of laser display technology field.Present embodiment is the laser display light source that adopts the laser head of embodiment 1 or embodiment 2.Fig. 6 is the structural representation of the laser display light source of present embodiment, and described laser display light source comprises light source group 601, coupled lens group 602 and fiber bundle 603.Wherein light source group 601 is by 10 laser constitutions, and 10 lasers all adopt the laser head of structure shown in the embodiment of the invention one, and coupled lens group 602 comprises 20 coupled lens, and fiber bundle 603 comprises 20 optical fiber.10 lasers are all launched the two-way laser beam, and 20 road laser beams of outgoing are in 20 coupled lens are coupled to 20 optical fiber respectively, and the laser output of 20 optical fiber is fixed as one group with fixture.Do not have the coherence because of between each laser institute emitted laser bundle in the above-mentioned light supply apparatus, can reach dissipation spot effect preferably, the two-way laser beam of same in addition laser emission generally has certain optical path difference, when the optical path difference of the light of two fiber optic conduction during greater than coherence length, two bundle laser can not interfere, and can eliminate speckle better.And, as can be known, do not possess the coherence between general a plurality of LASER Light Source in the prior art, so adopt a plurality of LASER Light Source can realize the spot that dissipates to a certain extent as display light source, wherein the effect of many eliminations speckle is obvious more more for the laser beam number.And the light source of the display unit of existing this class formation of employing all is lasers of single channel output, 20 bundle laser then need 20 lasers, adopt light supply apparatus of the present invention then can realize utilizing less light source to realize the purpose of output than multiple beam, compare with the existing light source of the display unit of this class formation that adopts, this light supply apparatus has been saved the laser of half, the volume of the effective light source that reduces, the while has reached the effect of better dissipation spot again.
Laser crystal among the present invention also can be Nd:YLF, Yb:YAG or Nd:Cr:GSGG crystal etc., frequency-doubling crystal can also be KTP, BBO, BIBO, KN or LN crystal etc., and the laser crystal in the different light paths and frequency-doubling crystal can adopt laser crystal inequality and frequency-doubling crystal.In addition, the present invention not only can be used for fundamental frequency light and two frequency doubled lights, also can produce frequency tripling, laser of quadruple etc., can also be used for simultaneously difference frequency light path and light path and parametric oscillation light path frequently, it is different and correspondingly change to some extent that its light path and plated film also can be as the case may be certainly.Electrooptic crystal in the embodiment of the invention one can be KTP, LiNbO
3, RTP, KD*P or BBO etc.; Polarised light conversion element 101 also can adopt Faraday polarization apparatus.In addition, in embodiment one and embodiment two, when the close together of first light path and second light path, can also adopt a laser crystal to replace first laser crystal and second laser crystal, replace first frequency-doubling crystal and second frequency-doubling crystal with a frequency-doubling crystal, replace first outgoing mirror and second outgoing mirror with an outgoing mirror, this moment, outgoing mirror can be level crossing.In embodiment three, laser crystal, frequency-doubling crystal or outgoing mirror can adopt a laser crystal, a frequency-doubling crystal or an outgoing mirror in a laser head, also can adopt the shared laser crystal of a plurality of laser heads, a frequency-doubling crystal or an outgoing mirror, adopt the number of crystal or outgoing mirror mainly to decide according to the concrete condition of light path, if light path is at a distance of too far away, adopt a crystal or outgoing mirror then can cause the waste of crystal or outgoing mirror, the raising of cost.Pump light of the present invention also can be modulated to acyclic pulsed light, except that square wave, can also be modulated to the pulse laser of forms such as triangular wave, sine wave.Below all it will be appreciated by those skilled in the art that.
It should be noted last that above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although the present invention is had been described in detail with reference to embodiment, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is made amendment or is equal to replacement, do not break away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.
Claims (17)
1. laser head comprises:
Pumping source is used to produce continuous laser;
Light-dividing device is used for the continuous laser that described pumping source produces is divided into two beam pulse formula pumping lasers; And
Two laserresonators are respectively applied for the described two beam pulse formula pumping lasers of reception and alternately export pulse laser.
2. laser head according to claim 1 is characterized in that, described pulsed pumping laser is a recurrent pulses laser.
3. laser head according to claim 1 is characterized in that, described pulsed pumping laser is the pulse laser of square wave form.
4. according to claim 1,2 or 3 described laser heads, it is characterized in that, the duty ratio sum of described two beam pulse formula pumping lasers is that 100%, two beam pulse formula pumping laser alternately produces, and wherein arbitrarily the duty ratio of beam of laser all in 25% to 75% scope.
5. laser head according to claim 1 is characterized in that described light-dividing device comprises polarised light conversion element and light splitting device.
6. laser head according to claim 5 is characterized in that, described polarised light conversion element is electrooptic crystal or Faraday polarization apparatus.
7. laser head according to claim 2 is characterized in that, the frequency of described pulsed pumping laser is that 50Hz is to 2KHz.
8. laser head according to claim 1 is characterized in that, comprises separately all in two described laserresonators that a laser crystal or two described laserresonators comprise a shared laser crystal.
9. laser head according to claim 8 is characterized in that, comprises separately also in two described laserresonators that an outgoing mirror or two described laserresonators comprise a shared outgoing mirror.
10. laser head according to claim 8 is characterized in that, comprises separately also in two described laserresonators that a frequency-doubling crystal or two described laserresonators comprise a shared frequency-doubling crystal.
11. laser head according to claim 1 is characterized in that, all places a coupled lens before two described laserresonators separately.
12. laser head according to claim 1 is characterized in that, described laser head also comprises the speculum that is used to adjust optical path direction.
13. laser head according to claim 1 is characterized in that, described laser head also comprises and closes the bundle output device, is used for that bundle is closed in the output of described two laserresonators and handles.
14. laser head according to claim 13 is characterized in that, described to close the bundle output device be light combination mirror, is used for that bundle is closed in the output of two laserresonators and handle obtains continuous laser output; The output frequency difference of described two laserresonators.
15. a laser display light source comprises light source group, coupled lens group and fiber bundle, it is characterized in that, described light source group is made up of the described laser head of at least one claim 1; Coupled lens in the described coupled lens group is one by one corresponding to the output beam of described laser head, be used for the output beam of described laser head respectively shaping be coupled in the corresponding optical fiber of described fiber bundle.
16. laser display light source according to claim 15, it is characterized in that, the quantity of the coupled lens of described coupled lens group is the twice of the quantity of described laser head, and the number of fibers of described fiber bundle equates with the quantity of the coupled lens of described coupled lens group.
17. laser display light source according to claim 16 is characterized in that, the output of described optical fiber is fixed as a branch of with fixture.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102540470A (en) * | 2011-03-10 | 2012-07-04 | 北京国科世纪激光技术有限公司 | Laser flare plastic device and laser flare plastic method |
| CN104020566A (en) * | 2014-04-28 | 2014-09-03 | 中国科学院上海光学精密机械研究所 | Two-dimensional large-scale laser beam array duty ratio adjusting device |
| CN109301684A (en) * | 2018-11-14 | 2019-02-01 | 西南技术物理研究所 | The solid state laser that diode is pumped in advance-normally pumped |
Family Cites Families (3)
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|---|---|---|---|---|
| CN1659753A (en) * | 2002-04-03 | 2005-08-24 | 埃斯科绘图有限公司 | Laser system |
| CN100384033C (en) * | 2005-05-30 | 2008-04-23 | 中国科学院物理研究所 | Active or passive controlling synthesizer of laser coherent |
| CN201340962Y (en) * | 2008-12-05 | 2009-11-04 | 北京中视中科光电技术有限公司 | Laser head |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102540470A (en) * | 2011-03-10 | 2012-07-04 | 北京国科世纪激光技术有限公司 | Laser flare plastic device and laser flare plastic method |
| CN104020566A (en) * | 2014-04-28 | 2014-09-03 | 中国科学院上海光学精密机械研究所 | Two-dimensional large-scale laser beam array duty ratio adjusting device |
| CN104020566B (en) * | 2014-04-28 | 2017-01-04 | 中国科学院上海光学精密机械研究所 | Two-dimensional large-scale laser beam array duty ratio adjusting device |
| CN109301684A (en) * | 2018-11-14 | 2019-02-01 | 西南技术物理研究所 | The solid state laser that diode is pumped in advance-normally pumped |
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