基于注入电流和工作温度的微小变化会引起半导体激光器输出光功率和光谱特性显著改变的特性, 研制了一种高稳定性半导体激光器控制电源。该电源利用场效应管和运算放大器组成恒流源为激光器提供高精度和高稳定的输入电流; 对感温电流源AD590或负温度系数热敏电阻采集的实时工作温度与预设温度的偏差进行比例积分微分运算, 控制半导体制冷器实现半导体激光器工作温度长期稳定。测试结果表明, 该电源输出电流0 mA～200 mA连续可调、电流精度0.01 mA, 0 ℃～50 ℃内温度控制精度±0.01 ℃, 长期稳定度10-5量级, 具有实时调节性能好、成本低、易实现等特点。

单光子数技术是量子光学领域中非常重要的一种技术,已被广泛应用于双光子符合探测及关联调控实验。通过一张单光子计数卡和一台路由器,利用双光子符合探测原理,采用分时复用的方法,构建了三光子符合测量的硬件系统,并基于LabVIEW实现了三光子符合计数系统的软件控制。该系统可以实现双光子符合计数和三光子符合计数、实时显示与存储。该系统对六波混频过程产生的3束光进行三光子符合探测,获得了较好的实验结果。该系统可应用于量子通信研究领域的经典光源,也可应用于非线性过程产生的具有时间-频率量子关联特性的其他非经典光源。

Fifth-order attosecond sum-frequency polarization beat (FASPB) is studied in a cascade three level system with the phase-conjugation fourth-order coherence function theory. An improved schematic diagram of geometry, which is different from that inducing fifth-order femtosecond different-frequency polarization beat (FFDPB), is used to obtain FASPB. By analyzing the cases that pump beams have either narrow or broad bandwidth, it is found that the temporal behavior of the sum-frequency polarization beat signal depends on the properties of the lasers and transverse relaxation rate of the atomic energy-level system. Finally, the cascaded four-wave mixing (FWM) processes and the difference between attosecond and femtosecond polarization beats have been discussed, it is found that cascaded or sequential lower processes can often obscure the direct fifth-order polarization beat processes.