放电激励重复频率HF激光器稳定输出实验研究

在放电激励重复频率气体激光研究中,激光器重复频率运行能量稳定输出是提高其输出平均功率及其实用化的基础。利用实验室已建立的单脉冲输出能量焦耳级的放电激励重复频率脉冲HF激光装置,通过调节气体介质循环速率及优化实验条件,开展激光器重复频率运行稳定输出实验研究,获得激光器重复频率运行时能量稳定输出的最佳工作条件。研究结果表明,随着运行频率的上升,激光输出能量衰减较快;增大气体介质循环速率有利于改善放电稳定性,提高激光器重复频率运行时输出能量稳定性。当混合气体工作介质以3.5m/s的流速循环时,激光器可实现1～50Hz重复频率激光输出,在重复频率50Hz运行时稳定输出能量约130mJ,能量波动约5%。     

管板式横流10kWCO_2激光器的实验研究

本文叙述一台具有重复脉冲辅助放电的横向流动连续CO_2激光器。实验研究了放电特性,并给出激光器增益和输出功率的实验和计算结果。激光器最大输出功率12600W。在输出功率10200W条件下一次充气连续运行超过8h,功率不稳定度±1.5％。     

TEACO2激光器比脉冲输出能量与预电离电子密度间的关系

本文从TEA CO_2激光器高压强脉冲辉光放电的简化放电模型出发,借助于放电形成时间,建立了TEA CO_2激光器输出的比脉冲能量与预电离电子密度间的关系式。依据前人的实验条件进行了具体计算,所得结果和前人的实验数据基本一致。     

紫外预电离TEA CO2激光器放电特性研究

结合电路分析了TEA CO2激光器的动态放电过程．综合考虑了气体放电中发生的电离、吸附及复合等碰撞过程,建立详细的参数模型,得到了电子密度、放电电流及放电电压随时间变化的波形,并将模拟结果与实验结果进行了对比;模拟并分析了放电回路中部分参量对放电特性的影响,获得了有利于激光器稳定放电的条件。     

望远镜谐振腔在高功率化学氧碘激光器上的应用

分析和实验研究了腔内放置的望远镜在高功率化学氧碘激光器上降低输出光束发散的应用，基于ＡＢＣＤ矩阵理论建立了一套用于分析望远镜谐振腔的理论公式，以放大倍数在２－４间的伽利略望远镜和我们的化学氧碘高功率激光器作为分析模型进行了理论计算。将望远镜放大光轴上适当位置，整个望远镜谐控腔就能方便地装到该模型激光器上，该激光器输出光束的发散和腔的稳定即能同时得到改善，在计算的一种条件下了实验研究，测得的发散角和     

1500W高频放电CO2激光器控制模型的研究

高频激励CO2激光器是目前正发展和研究的新一代工业用高功率CO2激光器,它具有很多优点:可实现大面积均匀稳定放电,有利于提高注入功率并有利于工作物质的激发,光束质量好,输出功率可调制,使激光器在连续、间断、脉冲方式下运行. 1500 W高频放电CO2激光器的控制模型由三部分组成:高频放电系统、激光谐振腔系统、气体循环冷却系统.本文结合这种激光器,讨论了影响CO2激光器的输出功率和输出光束质量的主要因素,分析了控制模型各部分的可控和可观测参数以及这些参数之间相互关系,探讨了建立控制模型方法和理论.通过分析已经取得的大量的实验数据和实验曲线,获取一个符合实际的高频放电CO2激光器的控制模型.(OE39)     

连续波超音速氧碘激光器小信号增益数值模拟研究

氧碘激光器是目前波长最短的化学激光器,受到了人们的普遍关注,近年来发展迅速.氧碘激光器的研究涉及气动力学、化学反应动力学和高能激光物理等众多学科.作者曾采用预混模型,对氧碘激光器的光腔流场和小信号增益进行了数值模拟,研究了不同化学配比条件对光腔流场和小信号增益的影响.本文在此研究基础上,根据氧碘激光器的实际混合过程,建立二维数值模拟模型,对氧碘激光器的光腔流场和小信号增益进行了计算,比较了两种混合模型对计算结果的影响,研究了不同化学配比条件对计算结果的影响.(PC2)     

紫外预电离TEA CO2激光器放电过程的数值模拟

建立了一数值模型模拟紫外预电离TEACO2激光器的放电过程。结合放电电路分析了激光器的动态放电过程,综合考虑了气体放电中所发生的电离、吸附、复合等粒子反应,得到了电子密度、放电电流及放电电压随时间变化的波形,并将模拟结果与实验结果进行了对比。此外,还模拟并分析了放电回路中部分参量对放电特性的影响,获得了有利于激光器稳定放电的条件。     

CO激光器Δν＝2受激跃迁小信号 增益系数的计算

本文对CO激光器的稳 态动力学模型作了修正和补充,通过计算机数值求解描述电子能量分布的Boltzman n方程和CO分子动力学方程,得到了CO分子电子基态中各个振动能级的粒子数分布,并首次 计算出不同放电参数下泛频受激跃迁(Δν＝2)的小信号增益系 数。计算结果对泛频CO激光器的设计和运行参数优化有指导意义。     

准分子激光器温度控制系统设计

设计了一种应用于准分子激光器的高精度温度控制系统,可对准分子激光器放电腔的温度进行实时采集、显示、控制,达到维持激光器腔体温度恒定的目的,从而改善激光器的工作性能如能量稳定性和使用寿命等。系统采用飞思卡尔单片机,以比例阀作为控温执行器件,并且设计了软硬件和优化的控制算法。实验结果表明：在三种不同PID控制方式下,系统控制精度皆能达到±0.2℃;在改进的智能PID控制下,系统超调变小、调节时间减少;在100Hz和500Hz不同重频条件下,系统采用智能PID控制时,运行稳定。因此,本系统可为激光器的运行提供良好的温度控制环境。     

External cavity controlled single longitudinal mode laser transmitter module

A GaInAsP/InP laser transmitter module incorporating an external cavity is described. It is shown that the cavity produces stable tunable single longitudinal mode operation of the laser even under high speed modulation conditions.     

High-power 1.02 mu m InGaAs/AlGaAs strained quantum well lasers with GaInP buried waveguides for pumping Pr/sup 3+/-doped optical fibre amplifier

High power 1.02 mu m single spatial mode laser diodes with low-loss (3.3 cm/sup -1/) GaInP buried waveguides have been developed for pumping Pr/sup 3+/-doped optical fibre amplifiers. A maximum CW light output power of 415 mW and an optical fibre output of 71 mW at 200 mA have been achieved. A preliminary lifetest showed stable operation for over 2300 h under 100 mW CW conditions at 50 degrees C.<>     

混沌控制双环掺铒光纤激光器的不稳定性输出

研究了双环掺铒光纤激光器的混沌控制问题,采用线性反馈控制对双环掺铒光纤激光器混沌系统进行了稳定控制,得到了双环掺铒光纤激光器具有稳定输出的充要条件.通过控制使双环掺铒光纤激光器不再有超混沌现象,并使双环掺铒光纤激光器系统具有任意所希望的稳定输出.     

Emission frequency stability in single-mode-fibre optical feedback controlled semiconductor lasers

A newly designed semiconductor laser emitter with adjustable linewidth by controlling the coupling to a single-mode fibre is described with emphasis on thermal requirements to obtain a high-frequency stability. A stable operation has been achieved during more than 1 h using an AlGaAs laser diode with optical feedback from a 50 cm-long single-mode fibre resulting in a 50-fold reduction of the spectral linewidth.     

1.5 µm range InGaAsP/InP distributed feedback lasers

Lasing characteristics of InGaAsP/InP distributed feedback (DFB) lasers in the 1.5 μm range were studied theoretically and experimentally. Wave propagation in five-layer DFB waveguides were analyzed to estimate the effect of the structural parameters on threshold conditions. A brief consideration on designing a low threshold laser and its lasing wavelength was made. DFB buried heterostructure lasers with fundamental grating emitting at 1.53 μm were prepared by liquid phase epitaxial techniques. CW operation was confirmed in the temperature rangeof -20° to 58°C, and a CW threshold current was as low as 50 mA at room temperature. A stable single longitudinal mode operation was observed both in dc condition and in modulated condition by a pseudorandom pulse current at 500 Mbits/s. No significant increase in the threshold current was observed after 1400 h continuous CW operation at 20°C.     

Complementary self-aligned laser by metalorganic chemical vapour deposition

A complementary two-step MOCVD growth technique for the self-aligned laser is described which eliminates any possible difficulty associated with regrowth on a high composition AlGaAs layer by placing the regrowth interface outside the stripe region. Single-longitudinal-mode operation with stable near and far-field patterns has been obtained to more than twice the laser threshold current.     

激光二极管抽运Nd:YAG晶体间歇振荡双波长激光器

报道了激光二极管(LD)侧面抽运Nd:YAG晶体间歇振荡1064 nm和1319 nm双波长激光器。采用间歇振荡技术,可有效地控制上能级的反转粒子数,避免激光振荡谱线之间的双波长竞争效应,而且对输出镜镀膜精度的要求大大降低,稳定的间歇振荡双波长激光输出较容易获得。两声光间的延迟时间连续可调,因此可以通过调节延迟时间来改变双波长激光的输出功率之比。在抽运电流为22 A,声光重复频率为4 kHz,延迟时间为10 μs时获得1319 nm激光偏振输出功率6.2 W,1064 nm激光偏振输出功率5.1 W。根据间歇振荡双波长激光器的四能级速率方程模型进行了数值计算和分析,理论结果与实验相符。     

Characterization and Studies on Hydro Dynamically Stable Operation of an Angular Jet SOG for COIL

Chemical oxygen-iodine Laser (COIL) is one of the fast emerging high power laser source for near Infrared (λ=1.315μm) laser generation. The heart of the system is the singlet oxygen generator (SOG) which is a pumping source for this laser. A Jet type SOG with a novel approach was designed and fabricated. Singlet oxygen was taken out of the SOG at an angle of 40° thus avoiding the carry over of droplets, which is one of the major drawbacks of horizontal system. The preliminary results have been reported in our earlier publication. The present paper discusses the performance of this generator for various operational conditions viz. diluent's gas nitrogen / helium, basic hydrogen peroxide composition, generator pressure and gas velocity. Further, conditions for the stable operation from generator as well as chlorine injection point of view have been identified.     

New instabilities of free-electron laser with an axial guide magnetic field

In this paper, the unperturbed orbits, their stable conditions and the single-pass gain of a free-electron laser have been treated with a single-particle theory to show the existence of a couple of new instabilities and moreover, to discuss their effects. Numerical analyses reveal that the new instabilities will probably affect the operation of free-electron laser when the guide field increases and get into the vicinity of its stability boundary.     

Sensitivity and stability of a radiation-balanced laser system

It has been previously shown that it is theoretically possible to build a solid-state laser that generates no internal heat. This is accomplished through a detailed balance of the stimulated and spontaneous emission. Such a device is called a radiation-balanced laser. Here, we analyze laser operation when conditions deviate from perfect balance. Sensitivity and stability analyses are presented for perturbations in the field parameters and temperature. We show that the radiation balance is a stable equilibrium under both transient and steady-state perturbations. Limits are derived on the magnitude of allowable spatial perturbations, and techniques for spatial mode matching are discussed. Numerical simulations of 1-/spl mu/m laser operation of Yb-doped potassium gadolinium tungstate are provided as an example.