CN100394652C - Set-up method of high-efficient full solid-state quasi-white light laser using cascade ultra lattice as frequency-changer crystal - Google Patents

Abstract

The present invention relates to a setting method of a full solid state quasi-white light laser device using a cascaded super lattice as a frequency changing crystal. A full solid state laser device which can output quasi-white lasers by using an optical super lattice which is formed by cascade connection of two sections of different structures as a nonlinear crystal is adopted, a semiconductor laser device is used as a pumping light source, and a dual wavelength (such as 1342 and 1064 nm) laser resonant cavity is used for generating dual wavelength lasers to be output; red lasers, green lasers and blue lasers with proper proportion are generated through a multichannel cascaded optical super lattice which is inserted in a temperature controlling furnace to be mixed into quasi-white lasers. The nonlinear crystal is formed by cascade connection of two sections of super lattices; the super lattice of the first section simultaneously realizes quasi-phase matching frequency doubling for dual wavelength fundamental waves which are output by a fundamental wave light source to obtain red lasers and green lasers; the super lattice of the second section is serially connected with the super lattice of the first section, and the super lattice of the second section can finish sum frequency of frequency doubling red lasers and infrared lasers with long wavelengths to generate blue lasers; generally, a multichannel periodic structure is adopted by the super lattice of the second section to be convenient for obtaining maximum efficiency and adjusting the proportion of blue lasers, red lasers and green lasers.

Description

With the cascade connection superlattice is the method to set up of the full solid-state quasi-white light laser of frequency-changer crystal

Technical field

The present invention relates to a kind ofly carry out frequency multiplication simultaneously and with frequently to realize the device of accurate white laser output with the multichannel cascade connection optical superlattice.It particularly is the quasi-white light laser of frequency-changer crystal with superlattice such as lithium tantalates.

Background technology

The RGB luminous power of accurate white laser output requirement output simultaneously is proportioning according to a certain percentage, is the important means that realize the output of RGB laser and utilize superlattice.If dual wavelength was exported near laser crystal can be realized infrared band 1300 and 1060nm, then utilize second order nonlinear effect to realize that RGB output then should comprise three parametric processes, forefathers' related work has in this regard:

People such as Liu Zhaowei have delivered the article of " AScheme to realize three-fundamental-colors laser based on quasi-phase matching is based on the design of coupling realization paracycle tricolor laser " on the Sold of calendar year 2001 VOl12 State Communications, reported with bi-period structure realized to the parameter of 532nm pump light and and process frequently, two cycles are respectively 1=11.9 μ m, L=8.74 μ m, the coupling temperature of design is 25 ℃.The power of ruddiness and blue light is respectively 0.38mW and 55.6 μ W.

People such as Liao Jun have delivered " Simultaneousgeneration of red; green; and blue quasi-continuous-wave coherent radiation based onmultiple quasi-phase-matched interactions from a single, aperiodically-poled LiTaO on the Applied Physics Letters of 2003 325 volumes ₃Aperiodic LiTaO ₃Output when superlattice are realized red, green, blue " article, reported and used output when having realized RGB light aperiodic.Use the semiconductor laser of launching 808nm as pumping source in the article, generation 1342 and 1064nm dual wavelength resonance, aperiodic, superlattice produced RGB light to while fundamental wave frequency multiplication and frequency tripling.Gross output was 18mW when pump power was 15W.Simultaneously referring to Chinese patent application: as Chinese patent and patent application 96117044,01108024,02138381,03112847.

People such as E.Cantelar have delivered " Red, green, and blue simultaneous generation in aperiodically poled Zn-diffusedLiNbO on the Applied Physics Letters of 2003 378 volumes ₃: Er ³⁺/ Yb ³⁺The LiNbO that nonlinear channel waveguide is acyclic polarized ₃: Er ³⁺/ Yb ³⁺Waveguide output when realizing RGB light " article.Use acyclic polarized LiNbO in the article ₃: Er ³⁺/ Yb ³⁺Waveguide realized RGB light time output.

First piece of article uses binary cycle cycle optical superlattice to realize the direct output of RGB light, is compared to green glow, ruddiness and blue light all a little less than; In second piece of article, used output when one aperiodic, superlattice were realized RGB; Then use acyclic polarized waveguide device to obtain the output of RGB light in the 3rd piece of article; Above scheme does not all relate to ratio how to control red, green, blue three coloured light and exports to obtain accurate white light.

Summary of the invention

The present invention seeks to: utilize multichannel cascade connection superlattice to realize 1342 and the frequency multiplication of 1064nm laser and the output of 1342nm frequency tripling, utilize the laser crystal such as the Nd:YVO that mix Nd ₄Generation 1342 and the output of the 1064nm double-basis glistening light of waves design the optical superlattice that two kinds of structure cascades are arranged, and wherein first segment structure can be realized accurate the frequency multiplication that is complementary, acquisition ruddiness and green glow simultaneously to the dual wavelength first-harmonic of first-harmonic light source output; Second section has multi-channel structure, connect with first section, this structure be used for infrared light and ruddiness with frequently produce blue light, different channel phases coupling temperature differences, phase place between the adjacency channel is joined temperature and is differed the 2-4 degree, and the red, green, blue export ratio can be by changing phase matching temperature and selection.We will be with the LiTaO of a binary cycle and periodic structure cascade among the present invention ₃Optical superlattice is an example.

According to LiTaO ₃, LiNbO ₃, KTP, the dispersion equation of crystal refractive indexs such as RTP can design the optical superlattice of specific binary cycle and periodic structure, and these superlattice can be to Nd:YVO ₄1342 and the 1064nm emission of lattice realizes frequency multiplication and frequency tripling efficiently, thereby constructs the small-sized all solid state laser that can realize efficient accurate white light output.

The present invention realizes the output of accurate efficiently white light in the following manner: by the semiconductor laser is pump light source, constitutes 1342 and the resonant cavity of 1064nm laser together with input mirror 3 and outgoing mirror 6; The frequency inverted device 9 of forming the output of above-mentioned dual wavelength with a multichannel cascade optical superlattice places the temperature control furnace 8 of pumping light path again, fundamental wavelength is 1342 and 1064nm, first section superlattice structure realized frequency multiplication simultaneously to two first-harmonics, obtain ruddiness and green glow, what second section different passage was corresponding different mates temperature with frequency, thereby can select suitable and passage frequency blue light according to the intensity of red, green glow, with proper proportion and the accurate white light output efficient, high stable that realizes red, green, blue.The present invention can select for use difference to mix the laser crystal of Nd, adopts theirs ⁴F _3/2-＞ ⁴I _13/2, ⁴F _3/2＞ ⁴I _11/2Two spectral lines excite, according to the emission wavelength of different crystal correspondence, design different multichannel cascade optical superlattices.

1. the present invention is applicable to that optical superlattice is pairing to the laser crystal that all contain the Nd ion ⁴F _3/2-＞ ⁴I _13/2, ⁴F _3/2＞ ⁴I _11/2Frequency multiplication and frequency tripling output are carried out in the spectral line emission.Such as Nd:YAG crystal and Nd:YAP crystal, the emission wavelength of their pairing this spectral lines is respectively 1319 and 1064nm and 1325 and 1053nm, and their available respectively this super crystal lattice materials obtain 660,532 and the accurate white light and 665 that red, green, blue constituted of 440nm wavelength, 527 and the accurate white light that red, green, blue constituted of 441nm wavelength.

2. the present invention comprises LiNbO ₃, KTP, RTP, LiTaO ₃Wait the optical superlattice of other nonlinear optical crystals, can realize according to the optical superlattice that above-mentioned laser crystal is designed ad hoc structure and structural parameters to the optical maser wavelength of correspondence the frequency multiplication and the frequency tripling of laser obtaining efficient accurate white light output according to the dispersion of refractive index of these crystal relation.

3. optical superlattice involved in the present invention can adopt different structures, comprises paracycle, binary cycle, aperiodic, cycle etc.Effective frequency multiplication that first section superlattice are wanted to finish the two spectral lines outputs of laser crystal in two superlattice of institute's cascade obtains ruddiness and green glow simultaneously, effectively the method for frequency multiplication is referring to existing method, as Chinese patent and patent application 96117044,01108024,02138381,03112847.Second section that want to finish second-harmonic red laser and long-wavelength infrared light with frequently produce blue light, second block of superlattice generally adopts the multichannel periodic structure so that obtain peak efficiency and adjustment blue light and ratio red, green glow.

4. white light is to mix with the red, green, blue three primary colors, and its ratio can be read from chromatic diagram (Fig. 3), and is different with the wavelength of three primary colors.For example when the red, green, blue wavelength was respectively 671nm, 532nm and 447nm, the only ratio of three should be 14: 1.5: 1.

To be how the example explanation realizes accurate white laser output below with one section seven channel period structure of one section bi-period structure cascade:

Bi-period structure is a kind of structure between cycle and paracycle, and this structure is subjected to the modulation in two kinds of cycles.This structure can provide two independently two of reciprocal lattice vector couplings parametric processes independently.We define two cycles that bi-period structure comprises and are respectively l, L (l＜L), the reciprocal lattice vector of bi-period structure superlattice can be written as:

$G_{m,n}=m\frac{2\mathrm{\π}}{l}+n\frac{2\mathrm{\π}}{L},$ M, n are integer.

The optical superlattice of periodic structure only is used for the frequency inverted of frequency multiplication and single parametric processes such as frequency and difference frequency usually.The reciprocal lattice vector of periodic structure superlattice can be expressed as:

$G=m\frac{2\mathrm{\π}}{\mathrm{\Λ}},$ Wherein the people is the cycle, and m is an integer.

In order to realize pro rata red, green, blue output by three parametric processes, we can use the binary cycle and the Periodic Superlattice of cascade.Effective frequency multiplication that first section binary cycle superlattice are finished the two spectral lines outputs of laser crystal obtains ruddiness and green glow simultaneously, second section Periodic Superlattice finish second-harmonic red laser and long-wavelength infrared light with frequently produce blue light, second section Periodic Superlattice generally adopts multi-channel structure so that obtain the blue light of proper strength.

In order to utilize maximum effective nonlinear coefficient, we have used (1,1) and (1 ,-1) rank reciprocal lattice vector of bi-period structure to compensate two position phase mismatches in the first-harmonic frequency multiplication process respectively.Bi-period structure two modulation period l, L respectively can under establish an equation and obtain:

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_1}({2n}_2-{2n}_1)=2\mathrm{\π}(\frac{1}{l}+\frac{1}{L})$

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_1}({2n}_2^{\′}-{2n}_1^{\′})=2\mathrm{\π}(\frac{1}{l}-\frac{1}{L})$

λ wherein ₁, λ ₂Be respectively fundamental wavelength 1342 and 1064nm, n ₁, n ₂And n ' ₁, n ' ₂Be respectively the refractive index of corresponding two groups of fundamental waves and frequency doubled light.

Second section periodic structure is used for compensating and the position of process frequently mismatch mutually, gets the single order reciprocal lattice vector equally, promptly

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_1}({3n}_3-{2n}_2-n_1)=\frac{2\mathrm{\π}}{\mathrm{\Λ}}$

Design for multichannel, can with the theoretical value periodic quantity of central passage, it is that central value increases progressively on one side that the cycle size of two wing passages can be worth with this like this, successively decrease on one side, the phase matched temperature of adjacency channel can differ some degree, such multi-channel structure can make the phase matching temperature broadening of frequency multiplication to 10-30 degree (is example with seven passages), guarantees to realize simultaneously and output frequently with frequency multiplication, and can control red, green, blue three's ratio by regulating working temperature and selector channel.。

We calculate refractive index with following dispersion equation

$n_e^2(\mathrm{\λ},T)=A+\frac{B+b\left(T\right)}{{\mathrm{\λ}}^2-{[C+c\left(T\right)]}^2}+\frac{E}{{\mathrm{\λ}}^2-F^2}+D{\mathrm{\λ}}^2$

Parameter wherein is:

A＝4.5284

B＝7.2449×10 ^-3

C＝0.2453

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

Have two variable λ and T in the above-mentioned equation, λ is the wavelength of first-harmonic, and T is the coupling temperature, and the coupling temperature is proper between 100 ℃ to 200 ℃ in practicality.According to above formula, for first section bi-period structure that is used for frequency multiplication, the coupling temperature is 110 ℃, and two cycle l and L are respectively 10.09 μ m and 32.3 μ m; Be used for realizing and frequently periodic structure that we have adopted seven passages for second section, the coupling temperature serve as that the interval increases progressively successively from 95 ℃ to 125 ℃ with 5 ℃.Calculating the corresponding cycle is 4.849 μ m, 4.854 μ m, 4.860 μ m, 4.868 μ m, 4.873 μ m, 4.873 μ m, 4.888 μ m.

Superiority of the present invention:

When realizing that with superlattice accurate white light is exported, subject matter is exactly how can be with the proportional control of red, green, blue three coloured light at a specific ratio, the introducing of any design and preparation error all will change two frequencys multiplication and one and the phase condition of process frequently, thereby influences the ratio of red, green, blue.The present invention adopts the cascade of two sections different structure superlattice, first section is adopted binary cycle, paracycle or other aperiodic structures frequency multiplication dual wavelength fundamental wave time on the spot, and the ratio that can regulate two frequency doubled lights by the Control work temperature, the superlattice of cascade adopt the multichannel periodic structure, blue light and phase matching temperature frequently differ some degree between the adjacency channel, thereby can regulate blue light and ratio red, green glow.The optical superlattice that adopts this thinking to design can obtain well-proportioned red, green, blue laser as the frequency inverted crystal, thereby obtains efficient, stable full solid-state quasi-white light output.

Description of drawings

Fig. 1 is a structural representation of the present invention

Fig. 2 is that the present invention is with cascade connection superlattice frequency-changer crystal structural representation

The C.I.E. standard chromatic diagram that Fig. 3 uses for the present invention

Embodiment

Provide experimental provision (Fig. 1) and cascade connection superlattice (Fig. 2) schematic diagram below:

In Fig. 1:

(1) semiconductor laser (LD), wavelength is 808nm;

(2) focusing system is generally set of lenses;

(3) input mirror is coated with multilayer film, HR@1342nm1064nm, HT@808nm;

(4) Nd:YVO4 crystal is used for producing 1342 and the laser medium of 1064nm wavelength;

(5) Q-modulating device;

(6) outgoing mirror is coated with multilayer film, T=4%@1342nm, T=72%@1064nm, HR@808nm;

(7) convergent lens;

(8) temperature control furnace is used for tuning temperature, wherein is placed with the superlattice crystal;

(9) cascade connection superlattice crystal is used for producing efficient accurate white light;

(10) condenser lens;

(11) the efficient accurate white laser of output;

Fig. 2 is the schematic diagram of multichannel cascade connection structure, and promptly 9 among Fig. 1 is bi-period structure for first section, is used for realizing two frequency multiplication processes; The periodic structure of second section seven passage is used for realizing and process frequently, in experiment, can select in seven passages one and fit adjustment working temperature to obtain the best proportioning of RGB luminous power and the accurate white light output of efficient stable.

Fig. 3 is the C.I.E. standard chromatic diagram, and the resulting RGB mixed lights of working temperature different shown in the figure all are in the accurate white light scope.

Claims (2)

1. with the cascade connection superlattice method to set up of the full solid-state quasi-white light laser of frequency-changer crystal, it is characterized in that adopting the optical superlattice of two sections different structure cascades is all solid state laser that nonlinear crystal produces accurate white light output, by the semiconductor laser is pump light source, and employing 1342 and 1064nm dual-wavelength laser resonant cavity produce dual-wavelength laser output; Insert by one that multichannel cascade optical superlattice produces the suitable red, green, blue three look laser of ratio in the temperature control furnace, be mixed into accurate white light; This nonlinear crystal is to be formed by two sections superlattice cascades, and first section superlattice realized accurate the frequency multiplication that is complementary simultaneously to the dual wavelength first-harmonic of first-harmonic light source output, obtains ruddiness and green glow; Connect with first section for second section, second section that want to finish second-harmonic red laser and long-wavelength infrared light with frequently produce blue light, second section superlattice adopts the multichannel periodic structure so that obtain peak efficiency and adjustment blue light and ratio red, green glow; Second section superlattice has multi-channel structure, differ the 2-4 degree with frequency phase matched temperature between adjacency channel, the ratio of red, green, blue realizes by different blue channel with light by changing working temperature, the structure of superlattice comprises cycle, paracycle or aperiodic, super crystal lattice material comprises lithium tantalate, lithium niobate or KTP, laser medium is for mixing Nd ion Nd:YAG, Nd:YLF or Nd:YAP, and the optical superlattice crystal is with the Nd ion ⁴F _3/2-＞ ⁴I _13/2, ⁴F _3/2-＞ ⁴I _11/2The wavelength that transition excited is a first-harmonic, realizes the clear full solid-state quasi-white light laser of semiconductor laser pump of accurate white light by accurate the mode that is complementary.

2. described by claim 1 is the method to set up of the full solid-state quasi-white light laser of frequency-changer crystal with the cascade connection superlattice, it is characterized in that designing for multichannel, with the theoretical value is the periodic quantity of central passage, it is that central value increases progressively on one side that the cycle size of two wing passages is worth with this, successively decrease on one side, the phase matched temperature of adjacency channel differs the 2-4 degree, multi-channel structure can make the phase matched temperature broadening of frequency multiplication to the 10-30 degree, can realize simultaneously with frequency multiplication and output frequently, and control red, green, blue three's ratio by regulating working temperature and selector channel.

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