光学脉冲的时域微分技术在时空测量领域有着重要应用，利用微分脉冲可使时空测量的精度达到或超越标准量子极限。分别利用双折射晶体和傅里叶脉冲整形系统两种方法对中心波长为813 nm、脉宽为130 fs的脉冲电场包络进行了一阶微分实验研究。利用双折射晶体得到的脉冲电场包络一阶微分能量转换效率为0.36%，电场强度的频谱分布只在中心频率附近的光谱半峰全宽范围内可与理论值较好地吻合，重合度达到91.36%，距离中心频率越远，与理论值差距越大。利用傅里叶脉冲整形系统得到的脉冲电场包络一阶微分能量转换效率达到11.10%，在空间光调制器的有效调制范围内，电场强度与理论值的重合度超过98.37%。与基于双折射晶体的脉冲微分方法相比，基于傅里叶脉冲整形系统的脉冲微分方法具有更高的能量转换效率，与理论值吻合的光谱范围更大，且能方便地产生任意阶数的微分脉冲，能更好地满足高精度时间同步领域的应用需求。

光神经拟态系统能以比生物大脑快几百万至十亿倍的运行速度模拟神经拟态算法, 优于电神经拟态硬件系统, 且其可胜任比传统光计算更复杂的计算任务。光神经拟态计算探索超快光脉冲信号的自适应性、稳健性和快速性, 能够避免传统数字光计算的芯片集成及模拟光计算的噪声积累等问题。本文报道了光子神经拟态信息处理的发展历程, 并从光子神经元, 光脉冲学习算法以及可集成光学神经拟态网络框架等方面介绍了光神经拟态计算的关键理论和技术。阐述了光神经拟态计算研究的必要性及存在的问题, 展望了其潜在的应用前景。

We investigate the angular distribution and average kinetic energy of ions produced during ultrafast laser ablation (ULA) of a copper target in high vacuum. Laser produced plasma (LPP) is induced by irradiating the target with Ti:Sapphire laser pulses of ～50 fs and 800 nm at an angle of incidence of 45o. An ion probe is moved along a circular path around the ablation spot, thereby allowing characterization of the time-of-flight (TOF) of ions at different angles relative to the normal target. The angular distribution of the ion flux is well-described by an adiabatic and isentropic expansion model of a plume produced by solid-target laser ablation (LA). The angular width of the ion flux becomes narrower with increasing laser fluence. Moreover, the ion average kinetic energy is forward-peaked and shows a stronger dependence on the laser pulse fluence than on the ion flux. Such results can be ascribed to space charge effects that occur during the early stages of LPP formation.

We design and demonstrate an all-optical temporal differentiator based on a simple Moire fiber grating operated in reflection. The simulation results prove that a single Moire fiber grating with only one \pi-phase shifted point can act as the first-order temporal differentiator and that a Moire fiber grating incorporating two symmetrical -phase shifted points can act as the second-order temporal differentiator. A practical Moire fiber grating is fabricated, thereby proving that such a grating can act as the first-order temporal differentiator. Our results verify the feasibility, flexibility, and accuracy of the proposed method.