High-sensitive terahertz detection by parametric up-conversion using nanosecond pulsed laser

A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric upconversion.A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the upconversion from terahertz wave to NIR laser was realized in a lithium niobate crystal.The minimum detectable terahertz energy of 9 p J was realized with the detection dynamic range of 54 d B,which was three orders of magnitude higher than that of commercial Golay cell.The detectable terahertz frequency range of the detection system was 0.90 Thz–1.83 THz.Besides,the effects of pump energy and effective gain length on the detection sensitivity were studied in experiment.The results showed that higher pump energy and longer effective gain length are helpful for improving the detection sensitivity of parametric up-conversion detector.

光学太赫兹辐射源及其在脑创伤检测中的应用

太赫兹波因其具有独特的优势,在生物医学检测、安全检查、通信和雷达等多种领域具有重要的应用前景,而太赫兹辐射源是太赫兹技术的应用基础,近年来得到了快速发展。基于光学非线性频率变换技术的太赫兹参量辐射源和差频辐射源可以产生调谐范围宽、输出能量高和单色性好的太赫兹波。本文综述了基于受激电磁耦子散射技术的太赫兹参量辐射源以及基于非线性光学差频技术的太赫兹差频辐射源的研究进展,着重叙述了当前太赫兹参量辐射源和差频辐射源在输出频率范围拓展、能量提高和快速调谐等方面的研究进展,以及太赫兹技术在脑创伤检测中的应用研究进展,并分析了光学太赫兹辐射源及其在脑创伤检测应用的关键技术问题以及发展趋势。