种子场对单池受激布里渊散射脉冲波形保真的影响

受激布里渊散射(SBS)产生池中引入种子光场，在种子场诱导下产生SBS，这不但可以降低SBS阈值，更可以获得最小的SBS脉冲形变，确保与抽运光波形基本一致，获得高波形保真.从理论和实验两方面研究了种子光强弱对脉冲波形保真的影响. 关键词： 受激布里渊散射 脉冲波形保真 注入种子     

受激布里渊放大光脉冲波形的研究

利用瞬态包含抽运抽空的SBS理论模型对布里渊放大器进行了数值模拟，给出了脉冲波形随 抽运光功率密度和种子光与抽运光能量比的变化规律，并用实验进行了验证，理论与实验符合得较好. 关键词： 布里渊放大器 脉冲波形 脉宽     

双级受激布里渊散射压缩获得高质量窄脉冲波形

针对受激布里渊散射(SBS)脉冲压缩系统中经常出现的波形调制现象,提出一种抑制调制、改善窄脉冲波形质量的新方法——双级SBS脉冲压缩结构。此方法以"两次压缩,子峰能量主峰提取"为控制手段,能够解决输出脉冲的多峰调制问题,有望成为获得高压缩比、高质量窄脉冲的一种新途径。提出并建立双级SBS脉冲压缩系统物理模型和数值计算模型,并利用典型SBS介质CCl4和FC-72开展了实验研究,获得无调制单峰结构的压缩脉冲,并与理论模拟结果符合较好。     

受激布里渊散射光脉冲波形的研究

从实验和理论上研究了受激布里渊散射(SBS)光脉冲波形.在Nd∶YAG调Q激光器中实验研究了SBS光脉冲波形随抽运光参数、结构参数和介质参数的变化规律，并利用SBS理论模型进行了数值模拟，实验与数值模拟结果的变化趋势基本一致.结果表明，抽运光能量越小，透镜焦距越短，镜-池间距越长，介质声子寿命越长，SBS光脉冲波形就越不容易出现调制现象.分析和讨论了抽运光参数、结构参数和介质参数对SBS光脉冲波形的影响机理. 关键词： 受激布里渊散射 脉冲波形 抽运光参数 结构参数     

高功率激光脉冲光纤取样的实验研究

光纤取样可以降低高功率激光脉冲时间波形测量成本，并提高测量系统抗干扰能力。光纤耦合效率、信号保真度、信号获取率是采用光纤取样测量高功率激光脉冲时间波形的难点。针对大型高功率激光脉冲宽度窄、光束口径大以及输出光束远场漂移量大等特点，设计了一套激光脉冲光纤取样系统，在全口径取样和不降低信号保真度的条件下有效解决了测量系统信号获取率低下的问题，充分保证了测量系统的可靠性。     

双布里渊放大池放大控制脉冲波形的研究

提出一种主放大池与修整放大池相结合的双布里渊放大池放大控制脉冲波形的新方法.在主放大池中，通过调节抽运光与种子光的延迟时间，完成对脉冲波形的整体控制；而在修整放大池中，通过调节双池间距，完成对脉冲波形、尤其是对脉冲前沿的微调.实验研究了双池间距对脉冲波形的影响，得到脉冲波形随双池间距的变化规律.结果表明：相遇时间及双池间距是控制脉冲波形最重要的参数.此双布里渊放大池系统可以方便地控制脉冲波形，尤其可以微调脉冲前沿. 关键词： 受激布里渊散射 布里渊放大 脉冲波形控制     

气体放电中纳秒脉冲波形的实验研究

在利用示波器测试交流电弧发生器的一级放电回路的振荡波形时,在主振荡波形中观测到纳秒脉冲振荡波形.针对纳秒脉冲振荡波形进行了实验研究和初步的理论分析,所采用的实验方法能够为气体放电的纳秒脉冲研究提供一种新的实验依据.     

抽运光对双布里渊放大池放大控制脉冲波形的影响

在传统的独立双池结构的受激布里渊相位共轭镜中,引入修整放大池,采用主放大池与修整放大池相结合的双布里渊放大池结构控制脉冲波形,主放大池控制脉冲的整体波形,而修整放大池对脉冲波形进行微调. 研究了抽运光功率密度对双布里渊放大池放大控制脉冲波形的影响,得到了不同抽运光功率密度下,脉冲波形随双池间距的变化规律. 研究表明,抽运光功率密度决定了种子光的放大效率,是控制脉冲波形的重要参数. 关键词： 受激布里渊散射 布里渊放大 脉冲波形控制     

脉冲激光在光纤中时间波形传输特性研究

给出了光纤传输激光脉冲波形特性测试的实验光路图，对比测量了经过空气传输和光纤传输两种方式的脉冲波形。实验测试了光束耦合到不同长度的单模和多模光纤与经空气传输后的时间脉冲波形，得到了激光脉冲波形的精细结构。实验结果表明，所选的多模和单模光纤经数百米传输后的脉冲展宽在容许误差范围之内，说明所选用的光纤可以作为纳秒激光时间脉冲波形测试的理想传输介质。     

超短光脉冲波形研究

本文讨论了光脉冲技术发展中的脉冲波形测量问题。介绍了一种通用的光脉冲波形测量新方法,该方法可以给出光脉冲的波形、脉宽以及光脉冲内含的频率啁啾信息。这种测量方法已应用于半导体激光器产生ps光脉冲的实验研究,其可行性得到了验证。     

Stimulated Brillouin scattering with high reflectivity and fidelity in liquid-core optical fibers

The characteristics of stimulated Brillouin scattering (SBS) in a liquid-core optical fiber (LCOF) contained CS₂ with 10?ns pulses at 532?nm wavelength are investigated experimentally. The threshold, reflectivity, pulse-shape (PS) fidelity, and phase-conjugation (PC) fidelity of LCOFs with different core diameters and lengths are measured. Threshold energy is as low as 2.5???J, and the SBS reflectivity, the PS fidelity, and PC fidelity exceed simultaneously 90?% when the input energy is over 20 times threshold.     

大信号布里渊增强四波混频理论研究

 针对高功率激光相位共轭装置的应用需求，阐述了布里渊增强四波混频（BEFWM）在这一领域的应用潜力，并就该大信号强相互作用条件下BEFWM的作用机理及输出特征进行了系统的理论研究，揭示了BEFWM瞬态响应速度、共轭光波形保真度及稳定性、能量转换效率均随注入信号光的增强而提高的作用特点，为该技术在中高强度激光相位共轭系统中的实际应用提供了理论依据。     

受激布里渊散射光限幅输出波形控制研究

数值模拟了种子场诱导受激布里渊散射光限幅过程的限幅输出波形特性.得到利用种子场控制限幅脉冲波形的规律：选取种子场脉冲宽度为抽运脉冲宽度的五倍，抽运脉冲相对于种子脉冲的延迟时间控制在与抽运脉冲宽度相当时，限幅输出波形最佳.限幅输出波形同时受抽运光功率影响，随抽运能量的增加，限幅脉冲功率不断下降，直至趋于0. 关键词： 受激布里渊散射 限幅输出波形 注入种子     

Deceleration and shape-transformation of light pulses during?phase conjugation in photorefractive media

We have theoretically investigated the main features of pulse deceleration and pulse-shape transformations during phase conjugation in photorefractive nonlinear media. The main attention in article is paid to the critical features which occur near the threshold of mirrorless oscillation. It is shown that the effects of critical enhancement when approaching the threshold do not lead to superior light slowing down characteristics as compared to the case of two-beam coupling. At the same time, essentially new features of pulse-shape transformation occur above the threshold.     

Generation of displaced squeezed superpositions of coherent states

We study the method of generation of states that approximate superpositions of large-amplitude coherent states (SCSs) with high fidelity in free-traveling fields. Our approach is based on the representation of an arbitrary single-mode pure state, and SCSs in particular, in terms of displaced number states with an arbitrary displacement amplitude. The proposed optical scheme is based on alternation of photon additions and displacement operators (in the general case, N photon additions and N − 1 displacements are required) with a seed coherent state to generate both even and odd displaced squeezed SCSs regardless of the parity of the used photon additions. It is shown that the optical scheme studied is sensitive to the seed coherent state if the other parameters are unchanged. Output states can approximate either even squeezed SCS or odd SCS shifted relative to each other by some value. This allows constructing a local rotation operator, in particular, the Hadamard gate, which is a mainframe element for quantum computation with coherent states. We also show that three-photon additions with two intermediate displacement operators are sufficient to generate even displaced squeezed SCS with the amplitude 1.7 and fidelity more than 0.99. The effects deteriorating the quality of output states are considered.     

Single-frequency high-energy Yb-doped pulsed all-fiber laser

A single-frequency pulsed all-fiber laser with a master oscillator power amplifier configuration is presented. While maintaining the properties of single mode, linear polarization, and narrow linewidth, a single-pulse energy of 260 μJ and over 500-W peak power is experimentally demonstrated at 1 kHz by employing tensile strain gradient and pulse-shape control methods. In addition, approximately 55 dB of optical signal to noise ratio is also achieved.     

Femtosecond pulse-shape modulation at kilohertz rates

We demonstrate a new scanning femtosecond pulse-shaping technique that allows pulse shapes to be modulated at kilohertz rates. This technique is particularly useful for lock-in measurements in which the signal is synchronized with the alternating pulse shapes. The pulse-shape lock-in technique is demonstrated in resonant coherent anti-Stokes Raman scattering, where it is shown to significantly improve the ratio of the resonant signal to both the nonresonant background and to noise.     

基于DRS4测试板的数字波形分析方法（英文）

使用不同的方法来确定La Br3晶体信号的到达时间。在文中信号经过光电倍增管的放大之后由DSR4测试板进行数字采集,其中DRS4是由瑞士PSI研究所生产的高带宽、低功耗以及快读出时间的开关电容阵列。这些优势使得DRS4很具有吸引力,很多实验将传统的ADC与TDC替换为DRS4。采集的波形可以通过不同的方法进行后续处理。其中包括:(1)恒分甄别、(2)波形拟合、(3)PMT脉冲模型法以及(4)均值过滤法。文中实现的恒分甄别的时间分辨与使用模拟电路获取的平均时间分辨相比没有提高。高斯波形拟合法虽然与数字CFD的结果相当,但是却更加耗时。均值滤波法虽然容易实现,但是通过这个方法得到的时间分辨与采样时间在一个量级。而PMT脉冲模型法得到的平均时间分辨为195.4 ps,优于模拟信号的恒分甄别的时间分辨254.7 ps。     

Characterization of sub-6-fs optical pulses with spectral phase interferometry for direct electric-field reconstruction

We demonstrate spectral phase interferometry for direct electric-field reconstruction (SPIDER) as a novel method to characterize sub-6-fs pulses with nanojoule pulse energy. SPIDER reconstructs pulse phase and amplitude from a measurement of only two optical spectra by use of a fast noniterative algorithm. SPIDER is well suited to the measurement of ultrabroadband pulses because it is quite insensitive to crystal phase-matching bandwidth and to unknown detector spectral responsivity. Moreover, it combines highly accurate pulse-shape measurement with the potential for online laser system diagnostics at video refresh rates.