CN101232149A - Setting method of cascade connection superlattice laser and dual wavelength laser based on intermittent oscillation - Google Patents

Abstract

The configuration method of a all-solid state white light laser based on intermittent-oscillation double-wavelength laser and cascade superlattice comprises following steps: constituting a efficient and stable white light laser by selecting a Nd<3+>-doped intermittent-oscillation double-wavelength laser as the fundamental wave light source and by adopting an optical superlattice with two different cascade structures as a nonlinear crystal to output red, green and blue laser beams in proper proportions; and disposing the optical superlattice with cascade structure in a temperature control furnace, wherein the optical superlattice has two segments; the first segment has a multichannel structure to achieve 1,319 nm frequency doubling and frequency tripling to obtain a 660 nm red light output and a 440 nm blue light output; the second segment is a periodical structure to achieve 1,064 nm quasi-phase matching frequency doubling to obtain a 532 nm blue light output; and the power ratio between two IR lights can be adjusted by adjusting the delay of the intermittent-oscillation double-wavelength laser, thus controlling the ratio of the red, the green and the blue lights to obtain a quasi-white light output.

Description

Method to set up based on intermittent oscillated dual-wavelength laser and cascade connection superlattice laser

Technical field:

The present invention relates to a kind of all solid state white light laser, relate in particular to a kind of intermittent oscillated dual-wavelength laser of using, realize stablizing all solid state laser of white light output with the optical superlattice of cascade structure as frequency-changer crystal as the first-harmonic source.

Background technology:

The only natural three primary colors of redgreenblue, the visible light of all colours can be mixed in certain proportion by RGB and obtained.Utilize RGB laser to realize panchromatic demonstration, color is abundanter, and color saturation is higher, can show abundant, gorgeous, the most real color of nature.It can be the important means that realizes RGB output as frequency-changer crystal and utilize optical superlattice according to certain ratio proportioning that white light laser requires the power of the redgreenblue light of output.If laser crystal can produce 1300 and 1000nm near the output of infrared dual wavelength, use second order nonlinear optical effect then can realize redgreenblue output so, relevant work has:

Calendar year 2001, people such as Liu Zhaowei have delivered the article of " A Scheme to realizethree-fundamental-colors laser based on quasi-phase matching is complementary based on accurate position and realizes the design of tricolor laser " on Solid State Communication, in this piece article, the parameter and the frequency process of 532nm pumping have been realized with bi-period structure, two cycles are respectively l=11.9 μ m, L=8.74 μ m, the coupling temperature design is at 25 ℃.The power output of ruddiness and blue light is respectively 0.38mW and 55.6 μ W, adds remaining 532nm green glow, has constituted redgreenblue output.And with reference to Zhu Shining etc. " the accurate position of superlattice was complementary and realized the generation Shi-ningZhu of frequency tripled laser paracycle; Yong-yuan Zhu; Nai-ben Ming; " Quasi-Phase-Matched Third-Harmonic Generationin a Quasi-Periodic Optical Superlattice "; Science 278,843-846 (1997) ".

2003, people such as Liao Jun have delivered " Simultaneous generation ofred; green and blue quasi-continuous-wave coherent radiation based on multiplequasi-phase-matched interactions from a single, aperiodically-poled LiTaO on Applied Physics Letters ₃Aperiodic LiTaO ₃Output when superlattice are realized quasi-continuous red, green, blue " article.Reported and used the semiconductor laser of 808nm as Nd:YVO ₄Pumping source, use simple two chamber mirror resonant cavitys to produce 1342 and the dual wavelength resonance of 1064nm, with aperiodic superlattice fundamental wave is exported when frequency multiplication and frequency tripling obtain RGB simultaneously.When pump power obtains the gross output of 15mW during for 15W.

Chinese patent application 200510038121 is that the applicant wishes that generation rather waits people's " is the method to set up of the high-efficient full solid-state quasi-white light laser of frequency-changer crystal with the cascade connection superlattice ".This application adopts the optical superlattice of two sections different structure cascades to produce accurate white light output as frequency-changer crystal, is pump light source by the semiconductor laser, adopts the dual-wavelength laser resonant cavity to produce dual-wavelength laser output; Produce a certain proportion of redgreenblue laser by a multichannel cascade connection optical superlattice of inserting in the temperature control furnace, be mixed into accurate white light.Used cascade structure optical superlattice, first section two wavelength to the first-harmonic source realized accurate the frequency multiplication that is complementary, and obtains ruddiness and green glow; Connect with first section for second section, major function be realize the infrared light of 1.3um and ruddiness with frequently produce blue light, second section ratio that adopts multi-channel structure to obtain blue light output efficiently usually and can adjust blue light and red-green glow.This patent only relates to the cascade structure optical superlattice and produces accurate white light output as the frequency-changer crystal of dual laser, does not mention intermittently dual laser and obtains stablize white light as the first-harmonic light source and export.

Chinese patent application 200510043830 is patents that people's application " a kind of intermittent oscillated dual-wavelength full-solid-state laser " is very waited in what capital.Mix Nd as common use of the dual laser in first-harmonic source ³⁺The laser crystal of ion ⁴F _3/2- ⁴I _11/2With ⁴F _3/2- ⁴I _13/2These two spectral lines (corresponding respectively to the emission wavelength of 1.0um and 1.3um) are realized, but these two spectral lines have common last energy level, brought the gain competition of dual wavelength output, thereby output are unstable.This patent as pumping source, is mixed Nd with semiconductor laser ³⁺The laser crystal two ends are provided with mirror after the optical path conversion mirror resonant cavity respectively, comprise that respectively Q-opens the light and two relatively independent public Nd of mixing of acousto-optic accent-Q resonant cavity of chamber mirror ³⁺Mirror behind laser crystal, what resonant cavity of optical path conversion mirror, two radiofrequency signals that the Q-switch driver is identical by repetition rate, have delay switching time drive two Q-switches respectively, mix Nd ³⁺Laser crystal only participates in a kind of laser generation of wavelength at every turn and amplifies.Thereby eliminated the laser output unsteadiness that the dual wavelength competition brings.This patent only relates to a kind of dual laser of intermittent oscillation, does not relate to optical superlattice and realizes efficient white light output as frequency-changer crystal.

Summary of the invention:

The objective of the invention is: adopt the semiconductor pumped Nd of mixing ³⁺The intermittent oscillated dual-wavelength laser is as the first-harmonic light source, and the cascade structure optical superlattice makes up all solid state white light laser of efficient stable as the frequency inverted crystal.

Purpose of the present invention can realize in the following way: based on the method to set up of all solid state white light laser of intermittent oscillated dual-wavelength laser technology and cascade connection superlattice, to mix Nd ³⁺The intermittent oscillated dual-wavelength laser (mix Nd ³⁺The emission wavelength of laser crystal is generally near 1.3um and 1.0um, for the crystal Nd:YAG that determines, wavelength is 1319nm and 1064nm) as the first-harmonic light source, optical superlattice with two sections different structure cascades produces the suitable redgreenblue laser output of ratio as nonlinear crystal, thereby makes up the white light laser of efficient stable.The optical superlattice of cascade structure places temperature control furnace, the optical superlattice of cascade structure has two sections, first segment structure is that a multichannel structure is used for realizing that the frequency multiplication of 1.3 μ m and frequency tripling obtain ruddiness and blue light output, and red blue power ratio can be by choosing different passages and adjusting crystal temperature effect and realize; Second segment structure is that periodic structure is used for realizing that accurate the frequency multiplication that is complementary of 1.0 μ m obtains green glow output.Regulate the time-delay of intermittent oscillated dual-wavelength laser and can regulate two power proportions between the infrared light, thus the ratio between the control RGB.

First section of optical superlattice has multi-channel structure, between the adjacency channel and the coupling temperature that frequently produces blue period differ 2 degree, thereby can be by changing temperature and allowing fundamental wave obtain blue light output efficiently and can regulate ratio between the red blue light by different passages.The structure of superlattice comprises paracycle, aperiodic, binary cycle, cycle etc., and the host material of optical superlattice comprises lithium tantalate, lithium niobate (comprising congruent, stoichiometric proportion and doped crystal) and KTP etc.

The first-harmonic source is semiconductor pumped intermittent oscillated dual-wavelength laser, and laser medium is that the laser crystal of mixing the Nd ion (comprises Nd:YAG, Nd:YVO ₄, Nd:YLF, Nd:GdVO ₄, Nd:YAP etc.), with Nd ^{3+ 4}F _3/2- ⁴I _13/2With ⁴F _3/2- ⁴I _11/2The wavelength that transition excites is a first-harmonic, and the laser crystal two ends are provided with mirror after the optical path conversion mirror resonant cavity respectively, comprises two relatively independent shared Nd of mixing of acousto-optic Q modulation resonant cavity of Q-switch and chamber mirror respectively ³⁺Mirror after laser crystal, the optical path conversion mirror resonant cavity, two radiofrequency signals that the Q-switch driver is identical by repetition rate, have delay switching time drive Q-switch and Q-switch respectively, mix Nd ³⁺Laser crystal only participates in a kind of laser generation method of wavelength at every turn, realizes the dual wavelength intermittent oscillation laser output of 1.3 μ m and 1.0 μ m.Dual wavelength takes the mode of intermittent oscillation to export to eliminate the problem of the unstable and pattern difference of power output that mode competition brings, realize redgreenblue output by accurate the mode that is complementary, thereby by regulate the Q-switching delay time regulate two infrared fundamental radiation optical output power ratios control red bluish-green between ratio, realize all solid state laser of efficient stable white light output.

Beneficial effect of the present invention: realize RGB than three blocks of laser crystals of traditional usefulness, three blocks of nonlinear crystals, with mixing Nd ³⁺Dual laser add optical superlattice, can realize realizing the output of RGB/white light with a laser crystal, an optical superlattice, make structure compact more, if three coloured light power of output can reach several watts respectively, will very wide application prospect arranged aspect the laser projection demonstration.The present invention as the first-harmonic light source, has eliminated the power output instability that mode competition brings with the intermittent oscillated dual-wavelength laser, can control the power proportions of two infrared lights by regulating time-delay simultaneously; With the optical superlattice of two sections different structure cascades as frequency-changer crystal, first section multichannel quasi-periodic structure, binary cycle, frequency multiplication, the frequency tripling of perhaps realizing 1.3 μ m aperiodic obtain red blue light output, by choosing suitable passage and coupling temperature, can control the power proportions of red blue light; Second section is adopted periodic structure to realize the output of frequency multiplication green glow.Like this, we can obtain stable well-proportioned RGB laser, thereby have realized all solid state white light laser of efficient stable.

Description of drawings:

Fig. 1 is a structural representation of the present invention

Fig. 2 is the TTL signal schematic representation that is used for controlling two Q-switching delay times

In Fig. 1: 1064nm front cavity mirror 1, modeling aperture 2,1064nm acoustooptic switch 3, polarizer 4, optical path conversion mirror 5, polarizer 6,1319nm acoustooptic switch 7, modeling aperture 8,1319nm front cavity mirror 9,1064nm acousto-optic driver 10,1319nm acousto-optic driver 11, TTL signal controlling 12, LD side pump Nd:YAG laser module 13, total outgoing mirror 14, condenser lens 15, the temperature control furnace 16 of two-way laser cavity, be used for tuning temperature, the superlattice crystal places and produces the efficient stable white light in the stove; Filter 17, the remaining infrared light of elimination becomes redgreenblue laser 19 so that measure white light power, spectro-prism 18, output white light after prismatic decomposition.

Embodiment:

1, the present invention is applicable to that all contain Nd ³⁺Laser crystal ⁴F _3/2- ⁴I _13/2With ⁴F _3/2- ⁴I _11/2Article two, the intermittent oscillated dual-wavelength laser of spectral line uses optical superlattice to realize the output of frequency multiplication frequency tripling RGB/white light as the first-harmonic light source.Such as Nd:GdVO ₄Crystal and Nd:YVO ₄Crystal, the emission wavelength of their pairing spectral line is respectively 1313 and 1053nm and 1342 and 1064nm, can realize 657,527 and the white light and 671 that constitutes of the RGB light of 438nm, 532 and the white light that constitutes of the RGB light of 447nm respectively with the cascade structure optical superlattice.Chromatic diagram according to standard is mixed into white light with red-green-blue, and its ratio is different because of the three primary colors wavelength.Such as when the RGB wavelength is respectively 660nm, 532nm and 440nm, the only ratio between three coloured light is: 7.1: 1.5: 1.

2, the present invention uses the host material of optical super lattice material, comprises congruent LiTaO ₃(CLT), congruent LiNbO ₃(CLN), stoichiometric proportion LiTaO ₃(SLT), stoichiometric proportion LiNbO ₃(SLN), mix the lithium niobate of MgO, the lithium tantalate of mixing MgO, KTP, RTP, etc. nonlinear optical crystal.Emission wavelength according to the dispersion of refractive index of different crystal material relation and different laser crystal can calculate the structural parameters of particular optical superlattice, thereby realizes the output of efficient stable white light.

3, the first of cascade optical superlattice involved in the present invention can use different structures, comprises paracycle, binary cycle, aperiodic, the cycle etc.But the frequency multiplication frequency tripling that will be able to realize 1.3 μ m spectral lines obtains red indigo plant and exports simultaneously, will adopt multi-channel structure to obtain efficient blue light simultaneously and export and regulate red blue power proportions.

To be the first-harmonic source with semiconductor pumped Nd:YAG intermittent oscillated dual-wavelength laser below, the optical superlattice of one section periodic structure of one section five-way road quasi-periodic structure cascade be a frequency-changer crystal, illustrates how to realize the output of efficient stable white light:

Experimental provision as shown in Figure 1.The first-harmonic light source is semiconductor pumped Nd:YAG intermittent oscillated dual-wavelength laser, and output wavelength is 1319 and 1064nm.Laserresonator is a Y die cavity, and two arms are respectively to 1319 and 1064nm wavelength export resonance, but shares the Nd:YAG laser module of a LD side pump.The acousto-optic Q modulation switch of two-way resonant cavity is controlled by Transistor-Transistor Logic level, but there is certain time-delay identical switching time in repetition rate, can allow two kinds of wavelength intermittent oscillations export like this, laser crystal only participates in a kind of laser generation of wavelength at every turn and amplifies, thereby has eliminated because the laser output that mode competition brings is unstable and the problem of pattern variation.Because the emission cross section of 1064nm approximately is 3.5～5.25 times of the 1319nm emission cross section, so allow the 1319nm spectral line prior to the vibration of 1064nm spectral line, as shown in Figure 2.Also as can be seen, the power output of 1319nm can reduce along with the increase of time-delay from the figure, and the power output of 1064nm increases simultaneously.

Introduce the structural design of superlattice below.Zong institute is known, so-called superlattice, be exactly in ferroelectric crystal non linear coefficient by periodic modulation, thereby the wave vector mismatch that can provide reciprocal lattice vector to come compensating non-linear to bring because of chromatic dispersion in interacting.Common structure has cycle, paracycle, aperiodic, binary cycle or the like.

Periodic structure is generally used for the frequency inverted of single parametric process, such as frequency multiplication and frequency, difference frequency etc.The reciprocal lattice vector of periodic structure can be expressed as follows:

$G=\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="S2007101910127E00011.png"\; state="\{\{state\}\}">m</figure-callout>}\frac{2\mathrm{\&pi;}}{\mathrm{\&Lambda;}},$ Wherein A is the cycle, and m is an integer, the exponent number of representing the position to be complementary.

For a plurality of parametric processes, produce blue light such as the frequency tripling process, must provide two reciprocal lattice vectors compensate respectively frequency multiplication with and the mutually mismatch in the process frequently, we use quasi-periodic structure to realize the frequency tripling of 1319nm here.The one dimension quasi-periodic structure can be regarded the cubic dot matrix projection point-blank of two dimension as, and common quasi-periodic structure is exactly the Fibonacci sequence, asks for an interview list of references [1] about the detailed introduction of quasi-periodic structure.The reciprocal lattice vector of quasi-periodic structure can be written as:

G _{M, n}=2 π (m+n τ)/D, wherein D is the average structure parameter, and m, n are integer, and τ=tan θ is the sine value of projected angle.

We use the paracycle of cascade and the output that Periodic Superlattice realizes RGB.First section five-way road quasi-periodic structure is used for realizing the frequency multiplication of 1319nm, and output when frequency tripling obtains red indigo plant is adopted five-way road structure can obtain blue light output efficiently and can be regulated power output ratio between the red basket; Second section periodic structure is used for realizing that the 1064nm frequency multiplication obtains the output of 532nm green glow.

In order to obtain maximum effective nonlinear coefficient, (1,1) and (3,4) two reciprocal lattice vectors that we choose quasi-periodic structure compensate the mutually mismatch in 1319nm frequency multiplication and 1319nm+660nm and the frequency process.Quasi-periodic structural parameters D and τ can obtain by following equation group:

$\frac{4\mathrm{\&pi;}{n}_{1s}}{{\mathrm{\&lambda;}}_1}-\frac{4\mathrm{\&pi;}{n}_{1f}}{{\mathrm{\&lambda;}}_1}=2\mathrm{\&pi;}(1+\mathrm{\&tau;})/D$

$\frac{2\mathrm{\&pi;}{n}_{1t}}{{\mathrm{\&lambda;}}_1/3}-\frac{2\mathrm{\&pi;}{n}_{1s}}{{\mathrm{\&lambda;}}_1/2}-\frac{2\mathrm{\&pi;}{n}_{1f}}{{\mathrm{\&lambda;}}_1}=2\mathrm{\&pi;}(3+4\mathrm{\&tau;})/D$

λ wherein ₁=1319nm, n _1f, n _1s, n _1tBe respectively the refractive index of 1319nm fundamental wave, 660nm frequency doubled light and 440nm frequency tripling light correspondence.

Five passages are used for realizing that the position phase matching temperature of frequency multiplication process generation ruddiness all designs at 140 ℃, and the coupling temperature of blue light serves as to launch on 140 ℃ of both sides of central temperature at interval with 2 ℃, can select suitable passage to realize that blue light is exported and can be regulated red blue export ratio efficiently like this.Utilize the dispersion equation of lithium tantalate to calculate refractive index

${\mathrm{<figure-callout\; id="2"\; label="n\; e"\; filenames="S2007101910127E00011.png"\; state="\{\{state\}\}">n</figure-callout>}}_e^{}=(\mathrm{\&lambda;},T)=A+\frac{B+b\left(T\right)}{{\mathrm{\&lambda;}}^2-{[C+c\left(T\right)]}^2}+\frac{E}{{\mathrm{\&lambda;}}^2-{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="S2007101910127E00011.png"\; state="\{\{state\}\}">F</figure-callout>}}^2}+D{\mathrm{\&lambda;}}^2$

A＝4.5284

B＝7.2449×10 ^-3

C＝0.2453

Parameter wherein is: D=-2.3670 * 10 ^-2

E＝7.7690×10 ^-2

F＝0.1838

b(T)＝2.6794×10 ^-8(T+273.15) ²

c(T)＝1.6234×10 ^-8(T+273.15) ²

Can obtain the quasi-periodic structure parameter such as the following table of five passage correspondences, wherein D _AAnd D _BBe the width of two constituent elements, l is the width (width of generally getting positive farmland equates) on positive farmland among two component As and the B:

	D A(μm)	D B(μm)	l(μm)	τ＝tanθ
					CH1(136℃)	9.19	14.952	4.59	0.209205
CH2(138℃)	9.19	14.946	4.59	0.207826
					CH3(140℃)	9.18	14.941	4.58	0.206441
CH4(142℃)	9.18	14.934	4.58	0.205056
					CH5(144℃)	9.17	14.930	4.58	0.203 667

Realize the 1064nm frequency multiplication for second section periodic structure equally, get the single order reciprocal lattice vector, 140 ℃ of coupling temperature, can obtain the corresponding cycle is 7.63 μ m.

Fundamental wave focuses on the superlattice inside of cascade structure through lens F, and the superlattice crystal is placed in the temperature control furnace to be heated to suitable coupling temperature, and temperature-controlled precision is 0.1 ℃.By the suitable passage of adjustment incident light process, and regulate suitable coupling temperature and the time-delay of Q-switch, can obtain stable efficient white light output.Emergent light is used the prism beam split behind the mating plate elimination infrared light after filtration, can obtain redgreenblue light.

Claims (4)

1. based on the method to set up of all solid state white light laser of intermittent oscillated dual-wavelength laser and cascade connection superlattice, it is characterized in that with the Nd that mixes of operation wavelength at 1064nm and 1319nm ³⁺The intermittent oscillated dual-wavelength laser as the first-harmonic light source, optical superlattice with two sections different structure cascades produces the suitable redgreenblue laser output of ratio as nonlinear crystal, make up the white light laser of efficient stable: the optical superlattice of cascade structure places temperature control furnace, the optical superlattice of cascade structure has two sections, first segment structure is that a multichannel structure is used for realizing that the frequency multiplication of 1319nm and frequency tripling obtain 660nm ruddiness and the output of 440nm blue light, and red blue power ratio is by choosing different passages and adjusting crystal temperature effect and realize; Second segment structure is that periodic structure is used for realizing that accurate the frequency multiplication that is complementary of 1064nm obtains the output of 532nm green glow; The power proportions between two infrared lights is regulated in the time-delay of adjusting intermittent oscillated dual-wavelength laser, thus the ratio between the control RGB.

2. the method to set up of all solid state white light laser based on intermittent oscillated dual-wavelength laser and cascade connection superlattice according to claim 1, it is characterized in that the optical superlattice structure that realizes the output of frequency tripling blue light is provided with five passages, different passages are to the coupling temperature difference of blue light, coupling temperature between the adjacency channel differs 2 degree, allows the incident fundamental wave obtain the output of blue light efficiently by different passages and regulates power output ratio between the red basket.

3. the method to set up of all solid state white light laser based on intermittent oscillated dual-wavelength laser and cascade connection superlattice according to claim 1 is characterized in that the first-harmonic source is semiconductor pumped intermittent oscillated dual-wavelength laser, and laser medium is Nd:YAG, Nd:YVO ₄, Nd:YLF, Nd:GdVO ₄Or Nd:YAP, with Nd ^{3+ 4}F _3/2- ⁴I _13/2With ⁴F _3/2- ⁴I _11/2The wavelength that transition excites is a first-harmonic, and the laser crystal two ends are provided with mirror after the optical path conversion mirror resonant cavity respectively, comprise Q-switch and chamber mirror respectively, two shared Nd that mix of relatively independent acousto-optic Q modulation resonant cavity ³⁺Mirror after laser crystal, the optical path conversion mirror resonant cavity, two radiofrequency signals that the Q-switch driver is identical by repetition rate, have delay switching time drive the Q-switch respectively, mix Nd ³⁺Laser crystal only participates in a kind of laser generation method of wavelength at every turn, realizes the dual wavelength intermittent oscillation laser output of 1.3 μ m and 1.0 μ m.

4. the method to set up of all solid state white light laser based on intermittent oscillated dual-wavelength laser and cascade connection superlattice according to claim 3, it is characterized in that the first-harmonic light source is semiconductor pumped Nd:YAG intermittent oscillated dual-wavelength laser, output wavelength is 1319 and 1064nm, laserresonator is a Y die cavity, two arms are respectively to 1319 and 1064nm wavelength export resonance, share the Nd:YAG laser module of a LD side pump, the acousto-optic Q modulation switch of two-way resonant cavity is controlled by Transistor-Transistor Logic level, but there is certain time-delay switching time in the identical acousto-optic Q modulation of repetition rate, make two kinds of wavelength intermittent oscillation outputs, laser crystal only participates in a kind of laser generation of wavelength at every turn and amplifies, the 1319nm spectral line is vibrated prior to the 1064nm spectral line, the power output of 1319nm reduces along with the increase of time-delay, and the power output of 1064nm increases simultaneously.

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