TRANSVERSE MODULATION OF BEAM PROFILES IN PUMP-PROBE CONFIGURATIONS WITH BaTiO3:Ce

Transverse spatial modulation of beam profiles for a probe beam counterpropagating to a pump beam in a 45°-cut BaTiO₃:Ce crystal with an externally applied electric field is studied numerically studied. For the case that the direct ion of the external field makes an angle of 45° with the c-axis of the crystal, the probe beam, which propagates in the direction perpendicular to the external field and has a waist wider than that of the pump beam, can acquire deep spatial modulation. In contrast, the pump beam shows no spatial modulation but diffracts only. For the case the external field is directed opposite to the direction mentioned above, the probe beam shows much stronger spatial modulation as compared to the pump.     

BaTiO3∶Ce晶体中两相干光束的相位共轭

从实验方面研究了两束相干光入射到BaTiO₃ ∶Ce晶体的相位共轭情况 .与一束光入射的自泵浦相位共轭相比 ,此相位共轭建立快 ,光强阈值低两个量级以上 ,易于实现 ,且在某些情况下相位共轭反射率大于前者 .利用四波混频理论 ,对其机制进行了数值研究 ,结果与实验吻合 .     

Fe:LiNbO_3晶体简并四波混频(DFWM)在光学图象处理中的应用

本文介绍Fe:LiNbO_3晶体在波长为6328A的低功率激光下的简并四波混频(DFWM)现象。给出了在不同泵浦功率下,共轭波强度随照射时间变化的实验曲线。验证了共轭波的位相补偿特性,并利用该特性校正了位相畸变的图象,得到了与理论相一致的实验结果。     

OPTICAL BISTABILITY IN A RING CAVITY WITH A PHOTOREFRACTIVE TWO-WAVE MIXER

We observed the phenomenon of optical bistability in a ring cavity with a photorefractive two-wave mixer. The experimental results are in agreement with those of theory.     

液晶混合光学双稳装置中的分叉、混沌和暂态行为

本文以时延弛豫微分方程为出发点,计算和分析了具有反馈时间延迟(feedbacktime-delay)t_R的液晶混合光学双稳系统中的分叉和混沌。还发现在双稳区内存在一种周期为t_R的暂态振荡。 关键词：     

利用胶片非线性特性提取密度切片

本文叙述了一种利用胶片非线性特性和正负片互补条件实现图象密度切片的新方法,提出了特性曲线的数学模型,讨论了密度切片反衬,γ和曝光量之间的关系,介绍了实验结果,方法的优点是使用非相干光,设备十分简便。 关键词：     

TRANSIENT BEHAVIOR OF THE SELF-PUMPED PHASE CONJUGATE BEAM BY THE CHANGE OF INCIDENT BEAM INTENSITY

We have studied the transient behavior of thc self-pumped phase conjugation when the incident beam is below the saturation intensity. We found that, when the incident beam intensity is changed abruptly, the intensity of the conjugate beam always decreases at first and then gradually increases to its stable value. This is due to the fact that the positions of the two coupled interaction regions are changed.     

微处理机在光学双稳态不稳定性研究中的应用

一、前 言 当前理论物理学一个活跃的课题,是研究流体、等离子体、非线性电路、Josephson结、化学、光学等系统中的湍流(chaos,turbulence)是通过什么途径产生的.当某一外界参数变化时,系统的行为将从有序状态(例如周期T)经过倍周期(period doubling)2T,4T,8T,…发展到无序(chaotic)状态.这是一种非线性现象,是非线性系统的普遍特征,不管该物理系统的内部细节如何,几乎都可以用同样的数学模型来描述. Ikeda在关于环行腔中非线性介质的光学双稳及其上肢不稳定性理论[1,2]里首先提出,当信号在腔内的反馈时间 tR》τ或tR《τ[3](τ是非线性…     

外加电场作用下BaTiO3:Ce晶体对Gauss光束的空间调制

从数值计算和实验两方面的研究表明,当一束Gauss光束通过处于外加电场中的BaTiO₃:Ce晶体时,在异常光偏振面内(或外加电场方向上)表现出很强的空间调制和自聚焦效应. 数值结果和实验观察完全一致.