提出一种新型的低截止电压环形阴极聚焦极控电子枪结构。在传统皮尔斯电子枪和杆控电子枪基础上，创新性地将球面阴极设计为环形发射区和不发射锥体区两部分，以实现更低的聚焦极截止电压，降低调制器单元的开关损耗，提升最大调制频率。研究表明，在导流系数为0.53 μP 的条件下，通过引入不发射锥形体，使阴极的截止电压降低一半，截止电压幅值由1 250 V降至600 V，对应电源调制器的等效调制损耗降低为1/4，可使最大调制频率提高4 倍，对电子对抗和雷达等应用系统的性能提升具有重要意义。

为实现弱信号对比度的高动态范围测量,基于二阶自相关理论,提出了一种实现纳焦级弱信号对比度高动态范围测量的方法。理论分析了能量(功率)、相位匹配和测量噪声对测量动态范围的影响,发现通过对测量噪声能量的光子计数进行探测、精确设置相位匹配过程中的非共线角,并采用聚焦和滤波方式对测量噪声进行抑制,可有效提升测量的动态范围。在此基础上,建立了一台弱信号高动态范围测量系统,利用神光II高能拍瓦激光种子源,实现了纳焦级弱信号1.0×10 11的高测量动态范围,这一数值与理论分析结果相符;同时,实现了种子源4.3×10 8对比度的准确甄别。研究结果对国内高能拍瓦激光系统对比度的提升具有重要意义。

在理论和实验上,分析了皮秒激光脉冲抽运所产生的参量荧光的时间相干特性。通过引入二阶复相干度,理论研究了在信号光与闲频光群速度走离存在的条件下,抽运功率和抽运脉宽对参量荧光时间相干性的影响。计算结果表明适当的抽运功率和较短的抽运脉宽是提升参量荧光时间相干性的重要条件,而过高的抽运功率或者较宽的抽运脉宽则会降低参量荧光的时间相干性。利用周期极化铌酸锂晶体,在实验上对理论结果进行了初步的实验验证。

Based on the premise that further improvements to the size and damage threshold of large-aperture optical components are severely limited, coherent beam combining (CBC) is a promising way to scale up the available peak power of pulses for ultrashort ultrahigh intensity laser systems. Spectral phase effects are important issues and have a significant impact on the performance of CBC. In this work, we analyze systematically factors such as spectral dispersions and longitudinal chromatism, and get the general spectral phase control requirements of CBC for ultrashort ultrahigh intensity laser systems. It is demonstrated that different orders of dispersion influence intensity shape of the combined beam, and high-order dispersions affect the temporal contrast of the combined beam, while the number of the channels to be combined has little impact on the temporal Strehl ratio (SR) of the combined beam. In addition, longitudinal chromatism should be controlled effectively since it has a detrimental effect on the combined beam at the focal plane, both temporally and spatially.

An attosecond precision and femtosecond range timing jitter measurement and control technique is proposed. It is based on the modulation of the combined pulse induced by relative time delay of individual pulses. The core of this timing jitter detection method is the integrated technique of optical cross correlation and electrical energy interferometry. To illustrate this technique, a proof-of-principle experiment is demonstrated based on two 237 fs pulses. The peak-to-valley timing jitter of the two pulses to be combined is less than 700 as in 1 h and the average efficiency of coherent beam combining could reach to 91.6%.

The capability of chirped-pulse compression and beam focusing of an object-image-grating self-tiling grating compressor is demonstrated in an optical parametric chirped-pulse amplification laser for the first time. Probe lasers for tiling error adjustments, which are generally required by the traditional tiled-grating compressor, are not needed in our demonstration any more. With the aid of the double-sized effective optical aperture of the second grating in the compressor, a 490 fs near-transform-limit pulse duration and a 90 μm near-diffraction-limit focal spot are obtained, synchronously, which are very close to the ones achieved by a non-tiled grating compressor with equal-sized individual gratings.

设计了一种用于替代现有商业化1053 nm飞秒锁模激光振荡器的方案。该方案通过光参量啁啾脉冲放大技术(OPCPA)实现能量放大和波长变换，产生作为基频光的3160 nm中红外激光脉冲，然后利用三倍频(THG)方式，实现高信噪比1053 nm脉冲输出。该方案的应用有望提升拍瓦激光装置的前端信噪比，进而改善整个装置的输出信噪比。

Object image grating self-tiling reduces difficulties of obtaining an ideal grating tiling condition by eliminating three tiling errors in six within a tiled grating. However, this may bring two potential problems: higher requirements of adjustment accuracy and maintaining stability. To examine the application values of this grating tiling configuration, the performance of object image grating self-tiling and traditional grating tiling configurations on accuracy and stability are compared theoretically and experimentally. Adjustment accuracy requirements of two grating tiling configurations are calculated, a comparative experiment of long-term stabilities is demonstrated, and relevant theoretical simulation analyses are developed to explain the experiment results.

拼接光栅技术是提高高功率激光器输出能量的一条可能途径，为保障高功率激光器光束时空光束质量，拼接光栅角度误差必须小于0.4 μrad，位移偏差小于20 nm。为了满足光栅拼接调整系统的高精度高稳定性要求，设计了光栅拼接旋转角度偏差检测方案用于测量两块相邻光栅之间的相对空间姿态。测量系统测量光束与压缩器主光束同轴，利用相移式干涉仪测量待测光，得到若干干涉图样，通过快速傅里叶变换还原波前得到相邻两块光栅相对空间角度偏差。通过实验验证了检测系统的理论可行性，目前在小口径光束下精度达到0.45 μrad。测量方案结合拼接光栅只需要测量波面倾斜误差的要求，简化了干涉测量光路及图像分析流程，有利于光栅拼接技术的工程化应用。