高频半导体激光器组件及其特性的研究

本文使用ＤＣ－ＰＢＨ型激光二极管芯片，设计制作了实用化封装形式的激光器组件；在理论上和实验上研究了组件的封装模型和小信号频率调制特性，其光响应３ｄＢ带宽大于１．８ＧＨｚ。该器件可满足六次群的光通信系统的带宽要求，也可用于ＧＨｚ级的微波副载波光通信系统。     

A method of making a true color stereoscopic hologram

A true color stereoscopic hologram is made with one-wavelength laser. Under illuminating incandescent lamp, a true color stereoscopic image can be seen from the hologram. A diffused reference light and a project object light are used in the recording of the hologram. The three primary color images of natural scenery are encoded on a white-and-black film. With the help of the encoded film, a true color hologram is recorded on a plate by single exposure and a true color stereoscopic by two exposures. The simplification of this method is apparent. Further more, it largely decreases the scattering noise of the hologram and averts the problem of color lack fidelity of the holographic image.     

Modeling and experimental investigation of short pulse Raman microchip laser

The results of experimental and theoretical investigations of passive Q-switch Raman microchip lasers based on Nd³⁺:LSB active medium and Ba(NO₃)₂ Raman crystal are presented. It has been demonstrated that intracavity Raman conversion in the microchip lasers is a simple and efficient method, capable of delivering high power pulses with sub-100 ps duration. Intracavity generation of the 1st Stokes pulses with duration from 180 down to 48 ps and a peak power of 48 kW has been performed and studied. High peak power and short duration of the 1st Stokes pulses in microchip laser with Ba(NO₃)₂ Raman crystal allows to easily perform extracavity harmonic generation and frequency sum mixing in LBO, BBO, and KTP crystals with discrete-tunable wavelength from ∼1200 down to ∼240 nm. We have developed a generalized model of Q-switched Raman microchip lasers, that takes into account spatial inhomogeneity of pump, laser, and Stokes beams, thermalization within the upper and lower multiplets of activator ions in laser medium, and saturable absorber bleaching and recovery. For the microchip lasers with different saturable absorbers, the model achieves very good agreement with the presented experimental results in a wide range of pump powers.     

High efficiency long pulse FIR Raman conversion in ammonia

Generally the quantum efficiency of FIR Raman generation in molecular gases is below the theoretical value. This disagreement is particularly evident in Raman scattering from pulsed sources with short pulse length, when the vibrational saturation limits the power conversion. Other nonlinear processes can overcome this saturation, but they require a very intense pump power for too short a time to use the FIR radiation in high sensitive experiments with heterodyne detection. This is the case, for instance, of RFWM. In this work we describe the experimental conditions to achieve a high efficiency 90 micron Raman conversion in ammonia, with both short and long pulses.     

Direct determination of gas velocity and gas temperature in an atmospheric-pressure argon-hydrogen plasma jet

Direct gas temperature and gas velocity measurements made in the exit plane of a subsonic argon-hydrogen thermal plasma jet from high-resolution lineshape analysis of laser light scattered by the plasma are reported. The lineshapes are in general a superposition of the ion feature of the Thomson-scattered light and the lineshape of Rayleigh scattered light. In the center of the jet Thomson scattering dominates while at larger radii Rayleigh scattering dominates. Because of the complexity of the lineshapes of light scattered by multicomponent plasmas, only those that are predominantly due to Thomson scattering can in practice be analyzed for gas temperature. Gas velocity can be determined from the Doppler shift of the lineshapes relative to the frequency of the incident laser if the velocity is greater than about 50 m s⁻¹. The maximum gas temperature measured was 14,500 K±5%. The maximum gas velocity measured was 1100 m s⁻¹±3%. Temperature values and the radial velocity profile are compared with those previously obtained from a subsonic all-argon plasma jet operated under similar conditions.     

激光溅射Cu等离子体与气相CH3CN团簇的反应

用激光溅射 -分子束技术研究了Cu等离子体与乙腈团簇的气相反应 .观察到Cu+ (CH3 CN) n、CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 和CH3 CHCN+ (CH3 CN) n 四个种类的团簇离子 .考察了等离子体作用于脉冲分子束的不同位置 ,对团簇产物的种类和尺寸大小的影响 .实验结果表明 ,Cu+ (CH3 CN) n 是由Cu+ 与乙腈团簇直接缔合而成 ,CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 主要是激光等离子体中的电子与乙腈团簇碰撞电离产生的 ,而CH3 CHCN+ (CH3 CN) n 是由乙腈团簇离子内的离子 分子反应生成的 .     

Spectroscopy of nickel chloride: Identification of the [15.0] Π3/2 and [15.0] Δ5/2 states

Vibrational bands belonging to the [15.0] ²Δ_5/2-A²Δ_5/2, [15.0] ²Δ_5/2-X²Π_3/2, and [15.0] ²Π_3/2-X²Π_3/2 electronic transitions of NiCl have been observed in the 14 000-16 000 cm⁻¹ region. The [15.0] ²Δ_5/2 and [15.0] ²Π_3/2 states are identified for the first time. The observed bands have been recorded at high spectral resolution using several techniques, which include intracavity laser spectroscopy (ILS), Fourier transform emission spectroscopy (FTS), and laser induced fluorescence (LIF) spectroscopy. For the ILS absorption spectra, NiCl molecules were produced in a nickel hollow cathode operated with a small amount of CCl₄. For the FTS emission spectra, excited NiCl molecules were produced in a King-type carbon tube furnace loaded with NiCl₂ and heated to 1600 °C. In the LIF work, NiCl molecules were produced by reacting laser-ablated nickel with PCl₃ seeded in argon. Detailed analysis of rotational transition lines indicates that the observed [15.0] ²Δ_5/2 and [15.0] ²Π_3/2 states are only separated by 10 cm⁻¹ and are interacting with each other. Molecular constants for these newly observed electronic states are reported.     

Theoretical analysis on phase-locking properties of a laser diode array facing an external cavity

External coupling model has been used to describe the output field of a laser diode array (LDA) phase-locked with an external cavity. The analytical solution for the coupling matrix equation of the phase-locked system has been obtained. The dependencies of the threshold gain, g_j of the system mode on the residue reflection of the front facet, r_f and round trip external cavity lengths, L have been discussed. The working lengths of the external cavity for stably phase-locking the LDA of different residual reflectivities have been calculated.     

用激光驱动冲击波测量高压状态方程的初步实验

 本文扼要介绍了以激光状态方程实验为目的而开展的铝靶烧蚀参数测量和激光冲击波实验，报道了这些实验的结果。     

激光聚变主放大器能源系统述评

 评述了激光聚变主放大器能源系统的演变过程。在简要评述传统能源系统的基础上，重点指出目前正朝向建立大型的能源组件实现模块化的方向发展，以减少系统元件数目，降低造价。结合NIF和神光Ⅲ原型能源模块的设计思路，述评了减少元件数目、降低造价、建造大型储能模块，以及采用大容量转换开关所带来的技术挑战和解决办法。同时指出开展能源单元技术(包括性能、风险、价格)研究是十分必要的。