具有OLED显示的智能化条纹相机(英文)

为了使条纹相机在一些特殊情况下能够使用良好,设计了一种基于PC-104、单片机8051和有机电致发光显示的智能化紫外皮秒条纹相机。相机的控制系统由数字化多扫速扫描电路、工作状态设置电路、像增强器选通电路和可程控化的高压供电系统构成。嵌入式PC-104通过控制I/O、A/D和D/A等接口来实现这些电路。该相机在自动调整参数、远程控制和系统自检方面都优于传统的相机。实验结果表明:控制系统稳定,时间分辨率优于100 ps,扫描非线性低于5%。     

Streak camera study of ultrashort pulse propagation in a weakly multimode optical fibre

A mode-locked dye laser in conjunction with a synchronously operating streak camera has been used to study ultrashort light pulse propagation in a weakly multimode optical fibre. Measurements of the intermodal temporal dispersion allowed the effective core radius a, the refractive index difference ? and the cutoff wavelengths of the LP21 and LP11 mode groups to be determined. The LP21 cutoff wavelength was experimentally verified and the temporal dispersion of the LP01 and LP11 mode groups investigated as a function of the fibre length.     

超短行波放大自发辐射的研究

用泵浦能量具有梯度分布的横向同步泵浦方案,产生超短行波自发辐射光脉冲。以N_2激光为泵浦源,获得约50ps的染料光脉冲输出,以锁模Nd:YAG倍频光作泵浦源,获得8～15ps光脉冲。用条纹照相机和光学多道分析器测量了脉冲波形和光谱。 计算机模拟了行波放大自发辐射的瞬态行为,计算结果与实验结果相符合。     

阴极门控光学条纹相机

为满足惯性约束聚变（ICF）物理实验诊断中对高信噪比低噪声光学条纹相机的需求,基于六电极同轴型扫描变像管发展了一种阴极门控光学条纹相机。该相机通过阴极预置直流高压叠加门控脉冲电压的方法,使相机变像管电压只有在门控脉冲加载时间内处于正常工作状态,才能对阴极发射的电子进行正常聚焦扫描,而在非加载门控脉冲时间内,变像管的第二聚焦电极处电压低于阴极电压,从而使阴极发射的光电子被反向截止,因此相机只对在门控脉冲加载时间内到达的有用信号进行测量,从而有效抑制了光学条纹相机受环境光辐照而引入的背景噪声,提升了相机的信噪比。验证实验表明,通过在阴极上加载幅度?5.5 kV、脉宽203 ns的门控脉冲电压,即可较大程度降低相机噪声,同时可维持相机的空间分辨率。     

Measurement of 1.3 and 1.55 ?m gain-switched semiconductor laser pulses with a picosecond IR streak camera and a high-speed InGaAs PIN photodiode

Gain-switched semiconductor laser pulses at 1.3 and 1.55 ?m were measured both with a high-speed InGaAs PIN photodiode and an IR synchroscan streak camera. Gain-switching characteristics and their bias dependence observed with both detection schemes are consistent with each other. Laser pulses of 24?30 ps duration are observed. Picosecond pulses from a gain-switched 1.55 ?m DFB laser are found to be chirped but not transform-limited.     

Picosecond optical pulse generation from an r.f. modulated AlGaAs d.h. diode laser

AlGaAs d.h. lasers with relatively low d.c. bias were demonstrated to be quite feasible for generation of a train of 30 ps optical pulses at a modulated frequency of below the GHz range. The pulse envelope width was measured by an s.h.g. correlation method as well as an ultrafast streak camera; the results agreed fairly well.     

Investigation of the characterstics of a mode-locked Nd:Glass laser with the aid of a picosecond streak camera

An infrared-sensitive streak camera, capable of resolving optical pulses of durations of ∼3 ps, has been used to analyze the temporal development of the individual picosecond pulses in a mode-locked pulse train. A progressive increase in the duration of the individual pulses throughout the pulse train is observed, the rate of increase in the pulse duration being an approximate quadratic function of the optical field. In addition, temporal analysis of the laser output signal, dispersively delayed with the aid of a grating pair, confirms the existence of phase-modulation effects during the development of the mode-locked pulse train.     

Simultaneous determination of the spectral and temporal properties of tunable, single, picosecond pulses from a short cavity dye laser

We report simultaneous quantitative spectral and temporal measurements of the output pulses from a single-axial mode rhodamine 6G short cavity (1-8 mum) dye laser. The dye laser was pumped at 10 Hz with single second harmonic (532 nm) pulses from a mode-locked Nd⁺³:YAG laser. Spectral measurements made with a high resolution spectrograph and temporal measurements made with an ultrafast streak camera indicate the production of Fourier transform limited pulses for near threshold operation. Output pulses of 7-14 ps (FWHM) are observed from the short cavity dye laser when pumped with 15-30 ps duration 532 nm pulses. The output pulse delay and jitter are also investigated. A theoretical model for the temporal evolution of the pulses is presented and compared with the experimental results.     

"星光Ⅱ"驱动铝靶产生热波、冲击波和稀疏波测量

在“星光Ⅱ”上 ,使用三倍频激光打三种厚度 (6 ,10和 2 0 μm)的铝介质平面靶 ,采用光学条纹相机记录冲击波图像 ,对热波和稀疏波进行测量 ,同时开展冲击波、热波和稀疏波三波相互作用规律的初步研究 ,采取多种措施成功地观测到冲击波在前、辐射热波在后、稀疏波更晚的三波物理图像     

InGaAs/GaAs单量子阱的瞬态光荧光特性(英文)

We used the time-resolved equipment consisting of a streak camera and normal photoluminescence set-up to measure the transcient behavior of the PL from the InGaAs/GaAs single quantum well sample, and thus obtained both the temporal resolution and the spectral resolution of the photoluminescence. A rapid decay of PL signal from the GaAs layer and the slow PL decay from the InGaAs well have beed found. From the experimetal results, the trapping efficiency of the carriers by the well is estimated to be about 80%.     

Generation of picosecond optical pulses with highly RF modulated AlGaAs DH laser

AlGaAs DH lasers with strong RF modulation superimposed on the relatively low dc bias below the oscillation threshold were demonstrated to be feasible for generation of a train of approximately 30 ps optical pulses at a repetitive frequency of sub-GHz range. The pulse envelope width was measured by three different methods: a fast response photodetector, the second-harmonic generation (SHG) correlation method, and an ultrafast streak camera. The results of the SHG correlation and the streak camera agreed fairly well. In order to explain the generation mechanism and the characteristics of these ultrashort optical pulses in a highly RF modulated semiconductor diode laser, the rate equation analysis was performed and the results were generally in good agreement with the experiment. Furthermore, from the computer simulation for the analysis of the SHG correlation traces, it was inferred that an individual ultrashort optical pulse has internal substructures made of fluctuating fields whose spike widths were of the order of subpicoseconds, due to the randomness of the phases among lasing modes.     

电子俘获材料的红外最小可激发阈值

在对撞脉冲锁模ＮｄＹＡＧ激光器产生的１．０６４μｍ超短红外脉冲激光激励下,采用参考光和测量光同时入射的测量方案,利用一台可见光条纹相机进行了电子俘获材料ＣａＳＥｕ,Ｓｍ的红外最小可激发阈值的研究,结果表明：在可见光条纹相机最小可探测能量密度Ｊｍｉｎ＝８．３×１０－１０Ｊ／ｍｍ２的条件下,测得电子俘获材料ＣａＳＥｕ,Ｓｍ的红外最小可激发阈值优于４．８×１０－９Ｊ／ｍｍ２。     

用于标定条纹相机的对撞脉冲锁模激光器

报道了一种被动皮秒对撞脉冲锁模Nd: YAG激光器的腔型及应用情况。用这样的对撞锁模脉冲激光器来标定皮秒条纹相机的非线性、触发晃动等得到了很好的结果。同时用条纹相机探测激光脉冲宽度也可以得到比示波器等设备准确的结果，最后得到输出脉冲宽度为10ps左右，比通常的反射式被动锁模脉冲宽度要窄3~5倍。     

用于激光聚变的X射线条纹相机阴极检测系统

研制了一套X射线条纹相机光电阴极检测系统,用于激光惯性约束聚变中阴极的快速标定和检测。通过三位一体的条纹变像管设计,条纹变像管电子光学系统的优化,真空室、控制系统的制备,系统的装调、集成和测试,研制了光电阴极检测系统。组建了阴极系统静态测试平台,标定了其静态特性,测试结果显示:3条条纹像中心的偏移率在狭缝方向为2.8%,在垂直于狭缝方向为6.6%,平均放大倍率1.29,误差在0.8%,边缘空间分辨率大于10 lp/mm。该系统可以满足激光聚变诊断研究对于X射线条纹相机光电阴极的检测需求。     

Direct measurement of chromatic dispersion in single-mode fibres using streak camera

For the first time the dispersion characteristics in a single-mode fibre in the 1 ?m-wavelength region is directly measured using a streak camera with a synchroscan streak tube having an S-1 photocathode.     

X射线扫描相机的标定

激光与等离子体相互作用过程都直接或间接参与激光等离子体发射的X射线.其标尺长度为几微米到几百个微米,特征时间为几个微微秒到几百个微微秒.因此诊断X射线时间分辨过程的仪器装置必须有微微秒到几百个微微秒的时间分辨率.X射线扫描相机就是专门为此目的设计研制的.X射线扫描相机正式使用前,应进行时间分辨率、动态范围、扫描线性、触发抖动并和反射镜、滤光片等谱分辨装置结合进行定量强度、线性输出范围的标定.1.时间分辨率标定X射线扫描相机的时间分辨率定义为δX光源输入,相应接收讯号最大值一半处的宽度(FWHM)     

A single-photon sensitive synchroscan streak camera for room temperature picosecond emission dynamics of adenine and polyadenylic acid

It is experimentally verified that a synchroscan streak camera, incorporating a microchannel plate and synchronizing with UV picosecond pulses generated inside the cavity of a mode-locked CW ring dye laser, has enough sensitivity to detect picosecond emission phenomena in the region of a single-photon event. To demonstrate the usefulness of the synchroscan streak camera, the first measurement of time- and wavelength-resolved emissions in the picosecond region is successfully carried out for adenine and polyadenylic acid aqueous solutions at room temperature, and shows that their shortest lifetimes, due to the monomer fluorescence, are 6 and 8 ps, respectively.     

Observation of sustained self-pulsation in CW operated flaredY-coupled laser arrays

The time evolution of the near-field radiation patterns of CW operated inphase locked flared `Y' coupled diode laser arrays has been observed with a streak camera. The arrays exhibit sustained self-pulsation at frequencies as high as 4 GHz     

Multi-frame de-raining algorithm using a motion-compensated non-local mean filter for rainy video sequences

This paper proposes a rain detection and removal algorithm that is robust against camera motion. The proposed algorithm initially detects possible rain streaks by using spatial properties, such as the luminance and structure of rain streaks. Then, the rain streak candidates are selected based on a Gaussian distribution model. Finally, these detected regions are improved with an advanced temporal property in a block-matching process. After the rain detection step, a non-rain block-matching algorithm for each block is performed between adjacent frames to find blocks similar to the block that has rain pixels. If similar blocks are obtained, the rain region of the block is reconstructed by spatio-temporal non-local mean filtering using similar neighboring regions. Finally, a specific post-processing is performed for visibility enhancement and flickering artifact removal. Experiment results show that the proposed algorithm uses only five temporally adjacent frames for rain removal but outperforms previous methods in terms of subjective visual quality.     

用条纹相机研究ps染料激光器的锁模动力学

本文在文献[1,2]，刁的基础上，结台激光器的实际腔型参数，在快和慢两种泵浦速率和不同染料浓度下计算了激光器的动态增益和脉冲特住。给出了染料激光器从不稳定状态到稳定锁模，再到不稳定运转的全过程。 