A pulse repetition frequency scaling law for the high repetition rate neutral barium laser

The variations in the output energy per pulse and in the average power output of the neutral Ba cyclic metal vapor laser as a function of the pulse repetition rate have been analyzed. At constant input power, the output energy per pulse is found to vary inversely as the two-thirds power of the pulse repetition frequency and so the average output power varies as the pulse repetition frequency to the one-third power up to the point where the Ba metastables do not have sufficient time to relax between pulses. Since the experiments which have been analyzed were conducted with a constant value for the laser discharge capacitance, these results imply that the output energy per pulse of this laser varies as the four-thirds power of the input voltage.     

高重复频率锁模单脉冲选择器

本文报道了一个分别用电触发和激光触发的冷阴极管和Blumlein线路构成的锁模脉冲选择器,用纵向Z切割的LiNbO_3晶体做普克耳盒,获得了约50％的开关效率,消光比大于1000:1,选取单脉冲几率100％,半波电压3.2千伏,开关延迟时间30～60毫微秒,抖动小于2毫微秒。器件在10次/秒的重复率下经长时间运转,工作稳定可靠。     

一种大功率高重频脉冲激光电源的研究

基于半导体激光器的用电需求,针对传统BUCK恒流源技术和储能电容线性放电输出技术的不足,提出了一种新的大功率高重频脉冲激光电源实现方案.通过对相关电路及结构进行的电性能及热仿真分析以及两台工程样机与激光器负载的对接实验,表明所研究的脉冲激光电源具有高重频、大功率、高动态响应、高同步精度等特点,输出的脉冲电流宽度、重复频...     

Compression of periodic optical pulses using temporal fractional Talbot effect

Recently, a novel method for compression of periodic optical pulses based on a superposition of replicated and time-delayed original pulse trains was proposed. In this paper, we experimentally demonstrate that the phase shift of these replicas, as occurs in the temporal fractional Talbot effect, leads to compression without repetition-rate multiplication, which is inherent in the previous method. Simple and compact devices based on fiber Bragg gratings or fiber/or waveguide splitters/combiners, used for implementation of the present method can be considered as an equivalent of dispersive delay lines for periodic optical pulses. The proposed devices will also be available, for instance, for pulse generation, pulse-chirp compensation, temporal imaging, and real-time spectrum analysis for periodic optical pulses.     

Tunable passive all-optical pulse repetition rate multiplier using fiber Bragg gratings

We demonstrate a tunable passive all-optical pulse repetition rate multiplier based on the fractional temporal Talbot effect. The multiplier comprises a series of identical linearly chirped fiber Bragg gratings (LCFBGs) interconnected via two multiport (N/spl times/N) switches. Discrete multiplication factors are obtained by simply using the switch to set the optical path of the input pulse train to be reflected by the required number of gratings, and hence, corresponding dispersion, to satisfy the Talbot condition. In our demonstration, we reflect an 8.62-GHz input pulse train from a cascade of one to four LCFBGs, resulting in discrete repetition rate multiplication factors of 12, 6, 4, and 3, respectively. We obtain output repetition rates exceeding 100 GHz; the multiplied train exhibits excellent signal stability with low amplitude ripple and timing jitter, and the output pulses are of similar duration to those at the input.     

超宽带无线通信中超高重复频率亚纳秒窄脉冲的生成方法

本文针对目前超宽带(UWB:Ultra Wideband)无线通信系统中窄脉冲信号产生存在的问题,面向未来高速无线个域网通信的需求,设计了一种适于CMOS集成的超高重复频率亚纳秒持续时间的超宽带脉冲信号实现的原理电路;其创新点在于从频域角度通过滤波来设计高重复频率的亚纳秒窄脉冲,而不是传统的从时域和器件角度来设计超宽带窄脉冲信号。文中给出了理论分析和电路测试结果。     

电子侦察脉冲列中重频信息提取与应用综述

脉冲重复间隔（PRI）或脉冲重复频率（PRF）是雷达辐射源最稳健的特征参数之一,体现了雷达辐射脉冲的时序规律。在功能上,重频既决定了雷达单值测距范围,又影响不模糊测速区域大小。现代雷达常采用多个重频值和多种调制类型以满足不同功能的需求。在非合作机制的电子侦察领域,PRI指2个连续脉冲上升沿的间隔,是重要的脉冲描述字（PDWs）之一。由PRI衍生的雷达重频信息包括典型重频值集、重频调制类型、重频参数时序模式,均需要从复杂的电子侦察脉冲列中提取之后才能应用至分选、识别等数据处理任务。从电子侦察系统中重频信息提取与应用的体制与技术难点出发,综述了3种重频信息提取与应用的研究现状,并对重频信息提取与应用的进一步发展做出了展望。     

小型化高重频窄脉冲声光Q开关DPL

介绍了小型化高重频声光Q开关DPL研制过程中的一些实验进展和相关产品样机。实验中,通过参数的优化选择,在激光二极管的泵浦峰值功率5 W,重复频率2 500 Hz下得到脉冲能量为81.5 μJ,脉冲宽度约为7.4 ns的激光输出,此时激光器的峰值功率为11 kW,光光转换效率14%,光束质量因子M2约为2.1。     

基于高SBS阈值的HNLF产生高重复频率超短光脉冲

基于光纤中的四波混频(FWM)产生高重复频率超短光脉冲的原理,并为抑制光纤中的受激Brillouin散射(SBS),采用非均匀掺杂高SBS阈值非线性光纤,通过FWM对双拍频信号进行整形压缩,实验上获得了100GHz的高重复率超短光脉冲序列,进而分析了入纤功率对输出光脉冲的影响。     

Design and characteristics of high pulse repetition rate and highaverage power excimer laser systems

The authors describe the design and the performance characteristics of an X-ray preionized discharge pumped XeCl laser system operated at very high repetition rate frequency and high average power (200 W). The laser system is mainly composed of a fast flow subsonic closed cycle wind tunnel, a laser head, a high average power electrical excitation system, and an X-ray preionization source. The laser head design and the damping of acoustic waves induced by fast electrical energy deposition of 50 J/L bar allows this device to be operated at repetition rate frequencies of up to ≈1700 Hz     

Generation of customized ultrahigh repetition rate pulse sequences using superimposed fiber Bragg gratings

We propose and experimentally demonstrate the use of superimposed fiber Bragg gratings (FBGs) as amplitude or phase filtering stages for generating ultrahigh-repetition-rate optical pulse bursts from a single ultrashort pulse. This approach offers the advantages of a compact all-fiber solution and provides high flexibility in tailoring the temporal features of the generated pulse sequence, namely, the repetition rate, as well as the shape and duration of both the individual pulses and the temporal envelope of the burst. To demonstrate the capabilities of the proposed approach, we generate near-flat-topped optical pulse bursts with repetition rates as high as /spl ap/170 GHz at a wavelength of 1.55 /spl mu/m using uniform and linearly chirped superimposed FBGs. We show that superimposed linearly chirped FBGs are more energetically efficient and provide increased design flexibility than superimposed uniform FBGs. Our experimental results also show the robustness of the technique to imperfections in the grating structures and to variations in the input pulse quality.     

Complete characterization of terahertz pulse trains generated fromnonlinear processes in optical fibers

The measurement technique of frequency-resolved optical gating (FROG) is used to characterize the intensity and phase of terahertz pulse trains generated from nonlinear and dispersive interactions in optical fibers. We show that existing FROG retrieval algorithms are easily adapted to allow the retrieval of periodic pulse characteristics and, using synthetic pulse trains generated from numerical simulations, we demonstrate how FROG can differentiate between periodic pulse trains with fundamentally different intensity and phase characteristics, yet qualitatively similar autocorrelation functions and spectra. Experimental results are presented for the FROG characterization of a 0.3-THz sinusoidal beat signal from a dual wavelength laser source, a 2.5-THz train of dark solitons generated in a high-birefringence fiber, and a 0.6-THz bright polarization domain wall soliton train generated in an ultra-low birefringence fiber. These results are shown to be in good agreement with nonlinear Schrodinger equation simulations     

High repetition rate CW fundamental soliton generation using multisoliton pulse compression in a varying dispersion fibre

A new method is proposed for fundamental soliton train generation from a CW double-frequency signal. This scheme uses multisoliton precompression in a fibre with sharply increasing dispersion followed by adiabatic compression in a dispersion decreasing fibre.<>     

The effect of CO2 laser pulse repetition rate on tissueablation rate and thermal damage

The ablation rate and thermal damage in skin produced by a superpulsed CO2 laser operating at pulse repetition rates between 1 and 900 Hz was measured. When delivering a fixed number of pulses (20 or 30) of equal energy, a 55-60% increase in the amount of tissue ablated was observed when the pulse repetition rate rose from 10 to 200 Hz. At pulse repetition rates greater than 200 Hz no further increase was seen. Under identical conditions, an 80% increase in the zone of thermal damage was observed when the pulse repetition rate was increased from 1 to 60 Hz. The large increases in tissue ablation and tissue damage may indicate the existence of a layer of mixed-phase (i.e., liquid and vapor) or metastable liquid which can store significant amounts of thermal energy between pulses. The data suggest that CO2 lasers should be operated at relatively low repetition rates for optimal performance.     

LD单端泵浦Nd:GdVO4声光调Q高重频窄脉宽激光器

激光二极管(LD)泵浦的Q调制高频率、窄脉宽、高峰值功率的固体激光器在激光雷达、激光加工等领域日益得到广泛的应用,而更高调制频率的固体激光器在将来会更受青睐.分析了泵浦功率和输出透过率两个因素在10～100 kHz调制频率下对脉宽的影响程度.研制了LD单端泵浦Nd:GdVO4声光调Q激光器,实现了重频100 kHz下窄脉宽激光输出.在重频为80 kHz时,获得脉宽17.7 ns,平均输出功率3.49 W,峰值功率2.46 kW和在重复频率为100 kHz时,获得脉宽19.6 ns,平均输出功率3.52 W,峰值功率1.79 kW的效果.     

基于SOS的高重频高压纳秒脉冲源设计

依据高重频高压纳秒脉冲输出的要求,基于半导体断路开关(SOS)的工作特点,设计了高重频高压纳秒脉冲源脉冲发生器线路。分析发生器线路的工作原理,对输出脉冲幅度50 kV/100 Ω、脉宽约10 ns~20 ns和重复频率100 kHz脉冲源的线路中关键器件的参数进行了计算。分析关键器件SOS、饱和脉冲变压器、副开关要求,给出了关键器件的选型参考。     

改进型多周期极化门产生高强度的阿秒脉冲

为了产生高强度单个阿秒脉冲,采用多周期极化门方案,利用空间非均匀极化门调控谐波辐射,在蝴蝶型纳米结构下产生高强度阿秒脉冲。结果表明,由于纳米结构表面的等离子共振增强现象,激光强度在空间呈非均匀性,导致高次谐波截止能量得到延伸,长量子路径对谐波的贡献被减弱;在极化门控制下,谐波平台区的贡献只来源于单一的谐波辐射能量峰,形成一个140eV的平台区;适当引入一束超短紫外光源,谐波强度增强2个数量级;通过叠加平台区的谐波,可获得一个持续时间在27as的超短脉冲,该脉冲强度比利用单一极化门方案获得的脉冲强度增强2个数量级。该研究对阿秒脉冲的产生以及阿秒科学的发展是有帮助的。     

Time-resolved two-photon excitation fluorescence spectroscopy and microscopy using a high repetition rate streak camera

We present a time-resolved two-photon excitation fluorescence spectroscopy and a simultaneous time- and spectrum- resolved multifocal multiphoton microscopy system that is based on a high repetition rate picosecond streak camera for providing time- and spectrum- resolved measurement and imaging in biomedicine. The performance of the system is tested and characterized by the fluorescence spectrum and lifetime analysis of several standard fluorescent dyes and their mixtures. Spectrum-resolved fluorescence lifetime images of fluorescence beads are obtained. Potential applications of the system include clinical diagnostics and cell biology etc.     

高重复率脉冲可调谐染料激光器在光谱学上的应用

本文报道利用高重复率脉冲可调谐激光器作光源所进行的光谱实验,获得脉冲激光作用下Ne的敏化荧光光谱、Ne-Cu灯的光电流信号的时间积分谱及Kr-U灯的光电流光谱。     

高重频脉冲激光对CMOS相机饱和干扰效果研究

激光干扰是对抗成像观瞄设备和精确制导武器,保护己力目标的重要方式。为了评估激光对CMOS像传感器的干扰效果,利用1.06μm高重频激光开展了对CMOS相机的饱和干扰实验研究,实验中计算了CMOS图像饱和激光功率密度阈值,并分析了CMOS相机干扰有效面积、饱和干扰面积、干扰前后图像相关度与激光入射功率之间的关系。实验结果表明．随着激光功率的增加。CMOS相机饱和像元数、干扰有效面积增加,图像质量下降,干扰效果明显提高