BaTiO_3晶体光折变效应振荡器和机理研究

在薄征Ce:BaTiO3晶体和体块Rh:BaTiO3晶体实现了光折变效应振荡器,利用前向二波耦合和相向二波耦合建立了光折变效应准线笥F－P腔模型,并从实验结果上进行了验证和分析,同时分析了光振荡现象对BaTiO3晶体的受激光折变散射自泵浦相位共轭的影响。     

Ce:Mn:LiNbO_3晶体光折变效应及应用

铌酸锂晶体非线性光学系数大,易于掺杂并能保证较高的光学质量,所以仍然是目前应用较广的光折变材料之一。本文报道铈锰双掺铌酸锂(Ce:Mn:LiNbo_3)的晶体的光折变效应及其在二波耦合和实时全息关联存储中的应用,并对实验结果进行了讨论和     

双掺杂LiNbO3晶体光折变效应研究

研究了系列不同掺杂、不同掺杂浓度、单掺杂和双掺杂以及不同后处理态(生长态、还原态和氧化态)铌酸锂晶体的透过率光谱和光折变二波耦合效应。实验结果表明，高掺杂铌酸锂样品的透过率光谱范围较窄；双掺杂样品比单掺铁样品的抗光折变效应增强，光折变效应降低。氧化态样品具有较大的透过率光谱范围；还原态样品具有较大的光折变二波耦合增益特性。     

光折变Bi12TiO20晶体中的波耦合性质

研究了光折变Bi12TiO20(TBO)晶体中的二波耦合矢量特性.对扩散记录全息求得信号光能量增益和偏振态改变的分析解,研究它们在3种制备可得的晶体切割面上随入射抽运光和信号光(不同)偏振方向、光栅取向以及晶体厚度的变化关系,并给出在任意光栅取向的取值范围.分析了信号光能量增益和偏振态改变量分别达到最大值时各向同性和各向异性耦合的作用,并研究旋光、压电及弹光效应在3种晶体切割面上对矢量波耦合的影响.     

双光子光折变晶体中全息屏蔽空间孤子

为了得到双光子光折变晶体中全息屏蔽空间孤子的结果,基于双光束耦合耗散系统和双光子光折变效应,证明了外加偏压的双光子光折变晶体中存在一种新的全息屏蔽空间孤子。此类孤子需要满足两种平衡,一是损耗与增益之间的平衡,增益由抽运光通过两波耦合为信号光提供;二是衍射与非线性之间的平衡,非线性包括外加电场的非均匀屏蔽和两波耦合对折射率的周期性调制。在信号光远小于抽运光的条件下得出了全息亮和暗孤子的解析表达式。研究了全息屏蔽孤子的演化特性。     

光折变的光学脉动现象及其非线性过程

报道了光折变LiNbO_3:Fe晶体中双光束耦合和四波混频的脉动现象。认为这种脉动现象起因于LiNbO_3:Fe晶体中的陷阱重复荷电波在光折变材料中感应出的运动折射率光栅。     

背向受激二波混频产生自泵浦相位共轭

本文讨论了在光折变晶体中,通过特殊的背向受激二波混频产生自泵浦相位共轭波的理论,并指出散射波的频偏是由于极化光折变晶体中的光生伏打效应引起相位栅的运动而产生的。     

掺铑钛酸钡晶体中温度增强的光折变性质

掺铑钛酸钡晶体是一种近年来生长成功的光折变晶体。人们对它的光折变性质如二波耦合、相位共轭、光致吸收等都做过很多研究。但关于其光折变性质随温度的变化尚未见报导。本文中我们对物理所生长的掺铑钛酸钡晶体的光折变性质对温度的依赖性进行了研究，发现其二波耦会强度及其相位共轭反射率随温度的升高而增加。在二波耦合实验中，我们用He－Ne激光器作光源，为消除强的扇光而采用o光偏振，两束对称入射（晶体外夹角2θ=18°）。泵浦光强度为0．36W／cm2，泵浦光与信号光的强度比为为20，测得二波耦合强度随温度线性增加，当温度从20℃…     

BaTiO_3相干光CW图象放大器

首次使用国产光折变晶体BaTiO_3利用两波耦合效应,成功地获得相干光CW图象(强度)放大。文中具体给出了放大率与泵浦功率,泵光与信号光比率,泵光与信号光相对晶体晶轴取回的依赖关系。     

BaTiO3相干光CW图象放大器

首次使用国产光折变晶体BaTiO3利用两波耦合效应，成功地攻得相干光CW图象（强度）放大。文中具体给出了放大率与泵浦功率，泵光与信号光比率，泵光与信号光相对晶体晶轴取回的依赖关系。     

Study on Fabry–Perot cavity consisting of two chirped fiber Bragg gratings

Combined the effective mirror surface model with the transfer matrix method, a detailed theoretical and numerical study on Fabry–Perot cavity consisting of two chirped fiber Bragg gratings is investigated. Results demonstrate that transmission responses of the Fabry–Perot cavity can be adjusted by changing the cascading sequences of the two gratings. When the two gratings are connected in the direction of same chirping, approximately uniform resonance and group delay are exhibited. However, some distinctive non-uniformity of the neighboring resonance peaks intervals is shown if the two gratings are cascaded in the opposite chirping sequences. In addition, for the Fabry–Perot cavity constructed by chirped-fiber-Bragg-gratings with different amplitudes or bandwidths, efficient resonances are achieved only in the common reflection range.     

Micro Fabry Perot light modulator for flat panel display

A new type of Fabry Perot light modulator for displays based on micro-electro-mechanical system technology is proposed. Multiple beam interference theory is used to design the modulator and analyze its characteristics. If Fabry Perot cavity length is one-quarter of the incident wavelength, the transmitted light is blocked by the modulator, and the modulator, which is illuminated from its backside, appears black. If the Fabry Perot cavity length is 0 or one-half of the incident wavelength, light may transmit the Fabry Perot modulator from its backside, and the modulator appears bright. Hence, the modulator may be used for flat panel displays. In this paper one Fabry Perot light modulator based on surface microma-chining technology is introduced. The designed modulator has a contrast ratio of 150 and can theoretically be driven by a voltage of 2.4 V.     

外赋式光纤F—P腔实现光学选频

本文利用外赋式全光行Ｆ－Ｐ腔进行光学选频，工对此器件的基本性质，特别是作为选频器的一些特性参数进行了分析与研究，设计了外赋式Ｆ－Ｐ腔的基本结构及结构参数，并分析了此选频器在不同腔长时的输出谱线特怀。     

基于可调谐珐珀滤波器的光纤珐珀传感解调系统研究

在光纤法珀（Fabry Perot.简称F-P）传感解调系统中，获取传感器反射信号的光谱成分是一种实用的方法，论文从可调谐珐珀滤波器波长选择特性的原理出发，提出使用可调谐珐珀滤波器获取传感器反射信号的光谱，从而实现光纤珐珀传感器的腔长信息解调，并在此基础上使用DSP为控制核心搭建了该系统，实验证明了方案的可行性。     

基于 Parylene 膜的法 珀干涉型光纤超声水听器

针对高强度聚焦超声(HIFU)声场测量,提出并研究了一种基于Parylene膜的法-珀干涉型光纤水听器。采用真空气相沉积法在光纤的端面蒸镀Parylene膜构成光纤水听器的法-珀腔,分析了光纤水听器的传感原理和解调原理,建立了HIFU声场检测的实验系统。实验结果表明,基于Parylene膜的法-珀干涉型光纤水听器能准确传感超声信号,其输出与换能器驱动电压的非线性度小于0.01,且与聚偏氟乙烯(PVDF)针式水听器的测量结果基本一致。     

光纤光栅F—P腔特性分析

本文以传输矩阵为基础,研究了光纤光栅Fabry-Perot腔的传输特性,导出了反射率、透射率和时延的理论表达式,讨论了腔长以及光栅的参数对其特性的影响。     

用可调谐法布里-珀罗腔测量光纤光栅波长

提出了一种利用压电陶瓷构成的可调谐法布里 -珀罗腔测量光纤光栅反射波长的方案 ,该方案可以直接将波长转换为电信号。阐述了该方案的基本原理 ,并讨论了在设计法布里 -珀罗腔时应考虑的几个问题。     

多外腔自混合干涉现象的理论与实验

考虑激光器外有多个反射体时所产生的自混合干涉现象，运用薄膜干涉理论，对弱光反馈条件下的多外腔自混合干涉理论进行了研究。基于复合腔激光器结构，建立了理论模型。理论分析构造了一个含有五个反射面的自混合干涉模型，模型是由三个外腔构成的多外腔自混合干涉。对模型进行了理论分析及数值仿真，得出在弱光反馈条件下，多外腔自混合干涉信号类似于传统的自混合干涉信号，为一类正弦波(外部反射率较小时)或类锯齿波(外部反射率较大时)。设计了实验系统，给出了实验结果并进行了验证。如果忽略多外腔的结构，理论所得结果与简单的三镜腔自混合干涉结构所得结果一致。     

Optically-Pumped Far-Infrared Laser Lines in Hydrazine, Methanol, Heavy Water, and Ammonia: New Laser Lines and Frequency Measurements

A far-infrared laser cavity designed to favor short-wavelength laser lines was used to generate optically-pumped far-infrared laser radiation. New far-infrared laser lines were discovered in hydrazine, heavy water, ammonia, and several short-wavelength lines previously discovered in methanol were observed. Wavelength, frequency, and relative intensity measurements were performed on laser lines in the wavelength range 42.4 to 253.7 μm. Each far-infrared frequency measurement was obtained by mixing the far-infrared radiation with radiation from two reference CO₂ lasers and from a microwave synthesizer in a metal-insulator-metal diode. The pump laser was a high-Q Fabry Perot resonator oscillating on 275 grating-selected laser lines including regular, sequence, and hot band lines.     

Studies of photorefractive properties of a novel dye‐doped nematic liquid crystal system

We examine here photorefractive and dielectric properties of a novel system: nematic liquid crystal mixture doped with 1‐(5‐methylfuran‐2‐yl)‐3‐(4‐dimethylaminophenyl)‐propenon dye. Kinetics of formation of refractive index gratings induced by light in a two‐wave mixing experiment in this dye‐doped nematic liquid crystal together with dielectric relaxation and ionic conductivity are investigated. We perform a degenerate four‐wave mixing experiment, enabling us to observe the generation of an optical phase conjugation signal by the studied system, and report on some optical microscope observations of hydrodynamic instabilities related to charge injection from the electrodes and ionic current flow through liquid crystal layer. We discuss the results in reference to other similar liquid crystalline materials. Copyright © 2000 John Wiley & Sons, Ltd.