在相位编码量子密钥分发系统中, 单光子干涉可视度决定了系统的成码率。本文提出一种优化单光子干涉可视度的方法, 即利用遗传算法和四通道偏振控制器实时补偿单光子偏振漂移, 同时利用时分复用参考光连续无复位地补偿单光子相位漂移, 最终在25 km光纤中实时优化的单光子干涉可视度达到98.6%, 相位编码量子密钥分发系统成码率为2.2 kbit/s。

Photosensitive fluorescent probes have become powerful tools in chemical biology and molecular biophysics, which are used to investigate cellular processes with high temporal and spatial resolution. Accordingly, photosensitive fluorescent probes, including photoactivatable, photoconvertible, and photoswitchable fluorophores, have been extensively developed during the past decade. The photoswitchable fluorophores have received much attention because they highlight cellular events clearly. This minireview summarizes recent advances of using reversibly photoswitchable fluorophores and their applications in innovative bioimaging. Photoswitchable fluorophores include photoswitchable fluorescent proteins, photoswitchable fluorescent organic molecules (dyes), and photoswitchable fluorescent nanoparticles. Several strategies have been developed to synthesize photoswitchable fluorophores, including engineering combination proteins, chemical synthesis, polymerization, and self-assembly. Here we concentrate on polymer nanoparticles with optically switchable emission properties: either fluorescence on/off or dualalternating- color fluorescence photoswitching. The essential mechanisms of fluorescence photoswitching enable different types of photoswitchable fluorophores to change emission intensity or wavelength (color) and thus validating the basis of the fluorescence on/off or dual-color photoswitching design. Generally the possible applications of any fluorophores are to label biological targets, followed by specific imaging. The newly developed photoswitchable fluorophores enable super-resolution fluorescence imaging because of their photosensitive emission. Finally, we summarize the important area regarding future research and development on photoswitchable fluorescent nanoparticles.

本文提出一种基于声光延迟效应消除脉冲光信号中微弱背景光噪声的方法, 利用两个串联的声光调制器组成的光学开关有效地抑制了与信号光同频率的背景光, 信号背景改善比达 13 dB。其中, 第一个声光调制器的作用是利用其对脉冲光的非线性光学延迟效应实现信号光与背景光在时序上的分离。第二个声光调制器将时域上已经和脉冲信号光分开的背景光消除。这种方法适用于精密测量和信息处理等领域的脉冲光信号的高灵敏检测。