Singlemode passive Q-switched ruby laser

Results are reported on a passiveQ-switched ruby laser utilizing a special rooftop prism cavity. With a 40 cm long resonator, a single transverse and longitudinal mode has been obtained. With a 3 meter long resonator, a single transverse mode self-locked beam has been obtained.     

高功率Q开关双脉冲红宝石激光器

本文叙述了双脉冲激光器的基本原理及调试方法，这个方法原则上可适用于其他类型KDP—Q开关高功率双脉冲激光器的研制（如钕玻璃，Nd：YAG双脉冲激光器）。     

Energy losses in a passive Q-switched ruby laser

An experimental investigation has been performed in order to explain why the output energy from a ruby laser is always reduced when passing from normal laser operation toQ-switching operation. A saturable absorber was used as the switching element; however, the discussion about the energy losses is valid for everyQ-switching system. Experimental data allow one to evaluate the decrease of the output energy due to the reduced pumping efficiency, to the losses in the optical switch, and to the incomplete depletion of the inversion arising from the spatial inhomogeneity of the standing wave in the resonator and from the relaxation processes in the ruby line.     

基于CPLD设计实现单横单纵激光器种子注入纵模锁定

基于自滤波非稳腔、种子激光注入及CPLD控制的干涉法纵模锁定技术,研制出一套单横单纵激光器系统；对激光器的工作原理及纵模锁定电路设计进行了说明。该设计具有输出光束质量好,工作稳定,抗干扰性强的特点。该激光器经历了在强干扰环境中长时间的“烤机”实验,单纵模锁定概率达100%。     

染料调Q红宝石激光视网膜损伤阈值研究

本实验用染料调Q红宝石激光照射青紫蓝灰兔60只眼,求得视网膜凝固出血损伤阈值和单纯出血阈值分别为361μJ/cm2和481μJ/cm2,95%置信限分别为330μJ/cm2～394μJ/cm2和451μJ/cm2～514μJ/cm2。     

单纵模被动调Q脉冲激光频率稳定性研究

采用脉冲波形观察、干涉条纹成像和角度光强扫描3种方法相结合,设计并建立了进行单纵模(SLM)被动调Q脉冲激光频率稳定性测量的实验装置,同步获得光滑的脉冲波形、面阵CCD上的多光束干涉图像和角度扫描F-P标准具的激光透射强度曲线,通过比对分析实验结果表明,该脉冲激光的长期频率稳定性为10-7量级。     

单模ns双脉冲红宝石激光器

提出了一种以Q红宝石激光器为基础的腔内剪切方案.     

A continuously pumped repetitively Q-switched ruby laser and applications to frequency-conversion experiments

A repetitivelyQ-switched ruby laser with 30-kW 30-ns pulses, suitable for many nonlinear optics experiments, is described. Using this laser SHG in KDP located outside the laser cavity yielded ≳ 4-kW pulses at 3472 Å with conversion efficiencies of ∼16 percent at the peak. A correction to existing SHG theories accounting for pump depletion (important at high conversions) has been calculated with the resulting improvement in agreement between theory and experiment. Experiments involving stimulated Raman scattering and vacuum UV generation from laser-produced plasmas are briefly described.     

Modulation and mode locking of the continuous ruby laser

The continuous ruby laser is operated with an external mirror; a modulating crystal (KDP) and a Brewster plate as polarization switch are used in the inner beam path. Coupling of the axial laser modes occurs if the frequency of a voltage applied to the KDP crystal equalsc/2L(=30 MHz). Instead of assuming equal mode intensities, these intensities are calculated from the condition of a minimum of the total losses in the resonator. It is found that these intensities differ largely in their magnitudes. A curve calculated for six locked modes corresponds exactly to the measured emission curve. If a modulating frequency other than the frequency separationc/2Lbetween adjacent longitudinal modes is chosen, the effect of the modulation on the stored energy within the laser averages out. Nevertheless, the intensity coupled out at the Brewster plate is modulated according to the term(varphi_{1} + varphi_{0} cosOmega t)^{2}. Some results of this coupling modulation are presented.     

Pulse stretching and shape control by compound feedback in a Q-switched ruby laser

Feedback control is employed to stabilize the output of aQ-switched ruby laser. A computational model of the rate equations plus feedback terms is used to examine pulse shapes with changing feedback parameters. It is shown that a lengthened flat-top pulse cannot be obtained with negative feedback alone, a compound feedback arrangement is suggested to facilitate this. A practical laser system is constructed with an associated feedback loop, good agreement is found between theory and experiment. Pulses flat to within ±5 percent are obtained with durations up to 600 ns and are amplified with no apparent saturation. Output powers of 15 MW are achieved for hundreds of nanoseconds with a divergence of 7 mrad and a spectrum consisting of transform-limited lines separated by the axial mode spacing.     

Simple single longitudinal mode Q-switched Nd:YAG oscillator

A simple three-mirror resonator is considered for longitudinal mode control in a passivelyQ-switched Nd:YAG laser. This configuration provides temporally smooth output pulses with duration determined by dye concentration and continuously variable from 300 to 10 ns. Previous problems with spatial beam quality can be minimized by careful arrangement of cavity components.     

561 nm全固态单纵模激光器

报道了一台激光二极管端面泵浦的全固态、单纵模561 nm黄光激光器。采用镀制窄带反射膜的方法来抑制增益较大波长的起振,并通过I类临界相位匹配LBO晶体腔内对1123 nm 基频光倍频及V型腔结构,选择单一波长运转,进一步通过F-P标准具选频方法,获得 561 nm 单纵模激光的稳定输出。在泵浦功率为2.4 W时,获得了80 mW的561 nm单纵模激光,光-光转换效率为3.3%,纵模线宽为24.1 MHz。该激光器在人眼黄斑病变治疗仪及流式细胞仪等生物医学领域,具有很高的实用价值,是近年全固态激光器的研究热点之一。     

Amplification properties of a tunable single transverse mode laser diode

The amplification properties of a tunable single transverse mode laser diode can be exploited to be used as ann times 1wavelength division switch. This kind of switch is expected to play an important role in telecommunications systems, especially when signals are not synchronous or when signal bit rates are various. The light amplification ratio between a desired main-mode wavelength and undesired submode wavelengths are improved by decreasing injection light power, and a ratio of 8.5 dB is achieved. This experimental result is in good agreement with theory. It is predicted theoretically using rate equations that the ratio is also improved by increasing the laser cavity mirror loss difference between the main mode and the submodes. A light amplification ratio of more than 11 dB is obtained when the cavity mirror loss difference is more than 50 cm^-1.     

Single high-order transverse mode surface-emitting laser with controlled far-field pattern

Single transverse mode vertical-cavity surface-emitting lasers (VCSELs) with high output power are important for high-speed data links, optical recording, laser processing, and so on. We demonstrate a single high-order transverse mode VCSEL with narrow trenches formed on its top surface by using a focused ion beam. The formation of four straight cross trenches resulted in the selection of a stable LP/sub 41/ mode oscillation. A large far-field angle of the LP/sub 41/ mode, which causes a low coupling efficiency even with a multimode fiber, was drastically reduced by loading a phase shift layer. A single-lobe far-field pattern with low scattering loss was realized by loading a spatial phase shift of SiO/sub 2/. We evaluated a coupling efficiency with a single-mode fiber including its alignment tolerance. The controlled far-field pattern enables lens-free direct coupling with a single-mode fiber even for large active-area VCSELs.     

关于非均匀性对单横模激光振荡特性的影响

考虑到激光的横模分布、介质增益及腔损失的横向不均匀性后,给出了不同激光模式振荡的速率方程,并讨论上述不均匀性对振荡条件、增益饱和特性、频率牵引、振荡功率等的影响。     

采用纵模匹配技术的短脉冲注入锁定染料激光器

本文报道了采用纵模匹配技术的短脉冲注入锁定染料激光器系统及实验结果.     

光纤激光器共腔法纵模选择技术

复合腔法光纤激光器谐振腔结构灵活,可以根据需要构成各种结构实现纵模选择.但稳定性差是制约其应用的主要原因,为提高光纤激光器纵模选择的稳定性及抗干扰能力,在复合腔基础上提出“共腔结构”光纤激光器这一概念.分别采用传输矩阵和自由光谱范围(FSR)两种方法详细分析了“共腔结构”光纤激光器的特性,理论分析证明:共腔结构可有效增...