连续Nd:YAG激光高重复率电光调Q研究

研究了连续Ｎｄ：ＹＡＧ激光器中由于热效应使ＹＡＧ棒产生的双折射引起传输的线偏振光退偏为椭圆偏振光的退偏现象所产生的输出不稳定和多模的原因。电光调Ｑ技术被应用于连续氪灯抽运的Ｎｄ：ＹＡＧ激光器件。为了获得稳定、单模的输出,在谐振腔内放置了一对λ／４波片。通过实验研究,实现了重复频率１～６ｋＨｚ的窄脉冲激光输出,这将为连续抽运的Ｎｄ：ＹＡＧ激光器提供一种新的电光调Ｑ技术。     

Generation of 17-TW 23-fs Pulses with a Two-Stage Ti：Sapphire Amplifier at Repetition Rate 10 Hz

We have developed a two-stage Ti：sapphire amplifier system which can produce 17- TW/23-fs pulses at a repetition rate 10Hz. A birefringent plate is used in the regenerative amplifier to alleviate gain narrowing, while an all- reflective cylindrical-mirror-based pulse stretcher and an acousto-optic programmable dispersive filter （AOPDF） are used to compensate for the higher order dispersion of the system.     

Conductively cooled 250-Hz single frequency Nd：YAG laser

A conductively cooled, laser diode （LD） end-pumped, injection-seeded single frequency Nd：YAG laser is designed and impleinented. The laser utilizes Nd：YAG rod as gain medium and compact dual-endpumping arrangement using two fiber-coupled LDs with a maximum output of 150 W. The optimized ramp-fire technique is applied to build reliable single longitudinal mode oscillating. The laser is capable of producing a 10-raJ Q-switched pulse with 13-ns pulse width at 1064 nm at a pulse repetition rate of 250 Hz. The output beam qualities M2 of approximately 1.19 and 1.22 in horizontal and vertical directions are detected, respectively.     

325 MHz and near transform-limited pulse output directly from an Er：fiber ring laser

A compact Er:fiber ring laser operated at a fundamental repetition rate of 325 MHz is reported.Two gain fibers with opposite dispersion are employed to shorten the fiber laser cavity for high repetition rate and soliton-like pulse generation without losing gain and compactness.The spectral bandwidth of the output pulse is 24 nm and the direct pulse duration is 123 fs without extra-cavity compression,which are values near the transform-limited range.     

250 kV，1 MHz重复率方波三脉冲源

 阐述了一种新的实现高功率高重复率方波脉冲源的技术途径，利用高压快恢复整流硅堆把三个独立的方波脉冲合成为一个MHz重复率的方波三脉冲。通过合理的串并联设计，可以提高硅堆在高频脉冲下的反向耐压，并使硅堆通过的正向脉冲电流达到kA量级。方波三脉冲源输出指标达到了电压250 kV，脉冲电流10 kA，峰值功率2.5 GW，重复率1 MHz，脉冲上升时间约40 ns，脉冲平顶宽度50 ns。     

被动调Q激光器输出特性的实验研究

被动调Q晶体Cr∶YAG对激光器的性能起着重要的作用。对Cr∶YAG被动调Q Nd∶YAG激光器进行了实验研究。着重研究了抽运功率、腔长、输出镜透过率以及初始透过率等因素对激光输出脉冲序列的重复率、脉冲宽度以及输出功率的影响。实验结果表明，抽运功率是影响重复率的最大因素，抽运功率的增大可以提高重复率，并减小脉冲宽度；它对腔长的影响效果刚好相反；存在一个可使输出功率最大的最佳输出镜透过率；不同的初始透过率对输出有一定的影响。分析表明被动调Q技术适用于DPL。     

一种新的基于正则化协方差矩阵特征值的角点检测算法

作为模式识别和图像处理领域的基本研究课题之一,角点检测在图像匹配与配准、目标识别与追踪、运动估计等方面都扮演着非常重要的角色.最小特征值方法(Eigenvalue)是一种有效的角点检测算法,但分析表明其对一致尺度变换不具有不变性.针对该问题,提出一种新的基于正则化协方差矩阵最大和最小特征值的角点检测方案(ERCM).该...