衍射光学元件的反应离子束蚀刻研究

本文提出了一种制作衍射光学元件的新方法——-反应离子束蚀刻法.对此技术研究的结果表明:反应离子束蚀刻法具有高蚀刻速率、蚀刻过程各向异性好、蚀刻参数控制灵活等特点,对于衍射光学元件和微光学元件的精细结构制作十分有利.本文详细总结了反应离子束蚀刻过程中各工艺参数对蚀刻速率的影响,并在红外材料上制作了Dammann分束光栅.     

三维形貌检测的自动参考栅象法研究

本文提出了一种用于曲面形貌检测的傅里叶变换法中的参考栅象图的自动产生及误差修正方法,通过对实际测量图象的处理,证明该方法具有很好的使用效果,从而大大提高了傅里叶变换法检测曲面形貌的精度和实用性。     

The effects of different dispersion compensation ratios on nonlinear single channel and WDM systems

The effects of the compensation ratio with dispersion post-compensation on nonlinear single channel and WDM systems with 10 Gb/s per channel are numerically investigated. When the transmission signal per channel is 10 Gb/s RZ pulse and the amplifier span is 50 km, proper undercompensation can enhance the performance of the nonlinear single channel system and the nonlinear WDM system. But the enhanced distance of the nonlinear WDM system is not as obvious as that of the single channel system, because the cross-phase-modulation effect plays an important role in the nonlinear WDM system.     

A novel quasi-phase-matching frequency doubling technique

A new quasi-phase-matching technique for efficient second-harmonic generation is reported. It is based on the spatial periodic modulation of the light intensity along the propagation direction, rather than the conventional spatial periodic modulation of the nonlinear optical coefficients. It can be realized by using a novel dual-channel waveguide frequency doubler structure for the desired light intensity distribution. This dual-channel waveguide device has major advantages including very small beam size, high light intensity within long nonlinear-waveguide interaction length, highly efficient second-harmonic generation, ease in fabrication of the nonlinear channel waveguides without any spatially periodic poling, and low waveguide propagation losses. The new quasi-phase-matching technique can also be applied to third-harmonic generation and other nonlinear optics processes.     

(e,2e)反应三重微分截面的计算

给出了利用BBK模型计算电子碰撞电离H,He⁺,He和Li⁺三重微分截面的通用方法,适用于中、高入射能量下的各种几何条件。计算结果与其它理论结果和实验数据进行了比较,符合得很好。     

块二级多分裂预条件迭代方法

提出一种块二级多分裂PE迭代算法(TSMPE),可以克服M^-1r^(s)并行化处理的困难。     

Steady-state populations of a driven three-level atom in a broad-band squeezed vacuum

A theoretical study is made of the steady-state populations of a three-level atom in a ladder configuration, driven by a superposition of a monochromatic laser wave with a broad-band squeezed vacuum. The master equation for the system and the atomic Bloch equations are derived. The steady-state populations are calculated numerically and shown graphically as functions of two-photon detuning for various cases of the squeezed vacuum. It is shown that, the atomic populations depend strongly on the relative phase of the driving field and the squeezed vacuum. When the phase matching condition is fulfilled, there will be a strong two-photon resonant absorption from the squeezed vacuum, a characteristic different from absorption of photons from a classical field. Received: 28 May 1997 / Revised and Accepted: 10 December 1997     

New Far-Infrared Laser Lines and Frequency Measurements of Acetaldehyde and Vinyl Fluoride

Eight far-infrared laser lines have been obtained by optically pumping acetaldehyde (CH₃CHO) and nine by pumping vinyl fluoride (CH₂CHF) with a cw CO₂ laser. The far-infrared laser structure used a metal-dielectric waveguide cavity. This is the first reported observation of four of the laser lines in acetaldehyde. In this work, we measure the frequency, optimum pressure of operation, relative intensity, relative polarization, and pump offset from CO₂ laser-line center.     

GRAIN SIZE DEPENDENT MAGNETISM IN GRANULAR MANGANESE PEROVSKITE La0.82Sr0.18MnO3

La_0.82Sr_0.18MnO₃ have been investigated. With grain growth, both an evident decrease of magnetization and the lattice distortions have been simultaneously observed. The phenomenon suggests a structure-coupled change of magnetism in the hole-doped manganese perovskite.     

光交叉连接节点的功能结构

光交叉连接(OXC)是未来波分复用光传送网实现交换与选路功能的核心部件.目前,OXC节点的物理结构得到深入研究,已经提出了一些采用不同光子器件的OXC实现方案.本文从描述光交叉连接功能的角度出发,给出一种分析OXC节点功能结构的模型,并比较各种OXC方案在功能结构上的差异。