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回顾并论述了光学相位共轭及四波混频技术的发展过程,介绍了四波混频相位共轭的原理、相关的介质材料、应用前景及技术发展趋势。 相似文献
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SHE Weilong 《Chinese Journal of Lasers》2000,9(3):249-254
Sincethediscoveryofmutualpumpedphaseconjugationinphotorefractivecrystals,anumberofdifferenttypesofmutualpumpedphaseconjugatorshavebeenfound,namely,thedualphaseconjugatemirror(PCM)[1],bridgePCM[2,3],incoherentbeamcoupler[4],birdwingPCM[5],froglegPCM[6],fishheadPCM[… 相似文献
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The generating mechanisms of nanosecond phase-conjugate (PC) signal and the time delay of a backward pump beam, at which the maximum diffraction efficiency of the PC signal can be obtained, are investigated using degenerate four-wave mixing in an erythrosin B-doped polyvinyl alcohol film. The influence of the coherence time of a pulse source on the measurement of the mechanisms of the PC signal generation is also examined. The population gratings due to saturable absorption of dye molecules mainly contribute to the PC signal generation rather than thermal gratings. The maximum diffraction efficiency is obtained at zero time delay of the backward pump beam, at which the coherence peak is observed. 相似文献
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We report on the simultaneous generation of phase-conjugate signals by degenerate four-wave mixing (DFWM) and holographic processes using a nanosecond pulse and a CW lasers in polyvinyl alcohol (PVA) films doped with four kinds of saturable absorbing dyes. For the pulse laser, of the four kinds of dye-doped PVA films, the erythrosine B-doped PVA and uranine doped-PVA films generate PC signals only by the DFWM process, while the other dye-doped PVA films generate PC signals simultaneously by not only the DFWM process but also the holographic process. Especially, the safranin T-doped PVA film generates strong PC signals by the holographic process. In contrast, all of the dye-doped PVA films generate the two types of PC signals for the CW laser. The fading of dye molecules is found to result in the generation of the holographic component of PC signals which governs the temporal behavior of the total PC signals. 相似文献
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Ce:KNSBN晶体中产生的双泵浦相位共轭 总被引:2,自引:0,他引:2
首次报道在Ce:KNSBN晶体中产生的“双”泵浦相位共轭现象,同时还观察到由同一“双”泵浦相位共轭光路所产生的自泵浦相位共轭和四波混频现象。 相似文献
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ZHONG Xiaoxia WU Jiada CHEN Shuchao WU Changzheng LI Fuming 《Chinese Journal of Lasers》1997,6(5):403-408
1.IntroductionOpticalphaseconjugationhasbeeninvestigatedextensivelybecauseofitswideapplicationsinimagingtechnology,phase--conjugationlasers,andopticalassociativememorysystems.Notedfortheirlargeopticalreorientationnonlinearities[IJ,nematicliquidcrystals(NLC)havebecomepromisingopticalmediaforapplicationsinthefieldofnonlinearopticsincludingnonlinearphaseconjugation.In1980,Feketectal.[2)firstrealizedphase--conjugationbydegeneratefour--wavemixing(DFWM)inNLCintheisotropicphase.Sincethen,thefie… 相似文献
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偶氮苯液晶薄膜相位共轭的光学记录研究 总被引:1,自引:0,他引:1
利用间并四波混频研究了一种偶氮苯液昌聚合物的相位共轭和光学记录特性,在近共振条件下,用低功率Nd:YAG倍频激光得到高效率的相位共轭光和高阶衍射光,当光强达到10W/cm^2量级时,薄膜显示出光记录效应,即在撒掉写入光之后,相位共轭波并不消失,进一步大光强到10^3W/cm^2量级时,出现三组分别只与前向泵浦光,后向泵浦光和信号有关的高阶衍射光。其中观察到第三阶衍射光,且在撒掉任两束光后,所剩一束 相似文献
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Phase conjugate matched filtering was performed with optical phase conjugation in Fourier-transforming backward degenerate four-wave mixing. A methyl-orange-doped polyvinyl alcohol (MO/PVA) film was used as a phase conjugator. The influence of the film thickness upon decay of a correlation signal due to phase mismatching was investigated. The thickness was varied from 15 μm to 90 μm. Reduction of the film thickness relaxes the tolerance for phase mismatching, which also occurs when a large reference picture is placed in a pump beam or when a reference picture shifts from the optical axis of the pump beam. Using a MO/PVA film of 15 μm thickness, we obtained allowable angles of 3.4° for a horizontally expanded reference picture and larger than 4.3° for a vertically expanded reference picture, assuming about 40% reduction of a correlation signal is allowable. 相似文献
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D. K. Mansfield J. F. Federici 《International Journal of Infrared and Millimeter Waves》1988,9(5):419-442
Using the results of Rogovin, the C. W. submillimeter phase conjugate reflectivities and response times of various prototype suspensions have been calculated for the degenerate four-wave mixing geometry. Assuming realistic liquid and particle optical constants as well as realistic submillimeter laser pump powers it is demonstrated that phase conjugate reflectivities approaching or exceeding unity could be expected in the strong pump limit for a wavelength of 100 microns. For longer wavelengths phase conjugation is not practical because the grating formation time exceeds the particle fall time hence no spatial grating can be formed. However, it is shown that if the particle buoyancy could be increased, phase conjugation could proceed with high efficiency at longer wavelengths. 相似文献
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Mn:KNSBN晶体中弱入射光高反射率四波混频相位共轭 总被引:1,自引:0,他引:1
功率为1mW左右的He-Ne激光束在Mn:KNSBN晶体中实现四波混频相位共轭。入射光相对于晶体主光轴的取向及入射光偏振组态对相位共轭反射率都有很大的影响。当物光近于布儒斯特角入射时,反射率可达60%。建立时间约为60sec的光折变光栅具有18hr左右的寿命。晶体中观察到诱导四波混频相位共轭。 相似文献
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A real-time detection of a moving object was demonstrated by taking the subtraction between cross-polarized phase conjugate waves with fast and slow response times with two kinds of dye-doped phase conjugators. One consists of superposed films of an erythrosin-B-doped film and a methyl-orange-doped film, and the other is a film dispersed with both dyes. The relative phase between cross-polarized phase conjugate waves by the both dye-dispersed films was stable. 相似文献
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非线性光学相位共轭及其在激光工程中的应用 总被引:2,自引:0,他引:2
非线性光学相位共轭是现代光学一个有生命力的分支,文章简单介绍了它的原理和产生相位共轭波的几种基本途径,重点介绍了它在激光工程中的可能应用与进展,并指出有待研究解决的问题。 相似文献
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分析了谱共轭技术用于补偿光纤色散和非线性的基本原理。通过对超高斯脉冲的数值计算表明,谱共轭技术(SPC)较时域相位共轭技术(TPC)能更好地恢复波形失真。为了弥补SPC不能补偿脉冲内拉曼散射的缺点,提出将SPC和TPC结合使用的方法。将其作用于光孤子串脉冲,不仅进一步优化了整形效果,而且还能有效抑制孤子自频移。 相似文献
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1IntroductionAconsiderableresearcheforthasbeenmadeduringthepastfewyearstodevelopopticallogicoperationsbasedonphotorefractivem... 相似文献
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The beam quality of a single-rod Nd: YAG laser with wavelength of 1.06 m was improved almost up to the diffraction limit by using a phase-conjugating mirror (PCM) based on stimulated Brillouin scattering (SBS) with acetone as the SBS medium. The new start cavity, which is the concave-convex cavity operating near the limit of stability in the g diagram, and the phase conjugation cavity of the SBS oscillator were designed. The thermal lens of the material with focal lengths of less than 140 m at pump powers of 60 J was compensated by the PCM. The laser is Q-switched by the nonlinear reflectivity of the PCM and the system works with an average repetition rate of about 5 kHz and single Q-switch pulse showed a width of 10 ns. It is demonstrated that if the start cavity is fit for SBS and the SBS phase conjugation mirror can be optimized, the beam quality of solid laser can be surely enhanced because of this technology of nonlinear optics. 相似文献
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Properties of a few saturable absorbers as candidates for low power optical phase conjugation (OPC) are examined. The specific
systems studied are the dyes eosin, erythrosin B and Rose Bengal, doped in gelatin, polyvinyl alcohol and boric acid glass
films. A method for quickly checking saturated absorption is suggested and demonstrated. Examples for OPC with these systems
are cited and limitations are briefly discussed.
An erratum to this article is available at . 相似文献