Terahertz imaging using an optical frequency comb source

Optical frequency combs, which are generated by the cascade of a phase modulator and a Mach–Zehnder intensity modulator, are used as a polychromatic signal source in the terahertz imaging system to improve imaging quality. The interference effect caused by the monochromatic wave has been greatly suppressed.The required optical power in the presented system is as low as～30% of that in the system using the Er-doped fiber amplifier as a source, which can reduce cost and protect photodiodes from damage. This work provides an effective, low power consumption, low cost, and easy way to realize terahertz imaging with high quality and can be used in future security inspections.     

跨阻放大器低温性能及其对THz光电信号的放大应用

随着太赫兹技术、低温电子学和射电天文学的发展,对可低温环境下工作的集成封装式跨阻放大芯片的需求增加。本文针对一种Ge-Si基底型跨阻放大器,主要研究了其深低温环境下的电学性能,获得了8 K温度下放大器芯片的典型端口电流-电压特性曲线和增益曲线,得到了在0.1～3 GHz频带内较为平坦的增益效果;为了验证其对太赫兹光电信号的放大功能,将该跨阻放大器与太赫兹量子阱探测器集成封装,并搭建了太赫兹脉冲激光探测系统,在8 K温度下实现了对脉宽2μs太赫兹光电探测信号的有效放大,跨阻增益约560Ω,电流放大增益为1.78 mA/V。上述研究成果首次验证了商用跨阻放大器在深低温环境下应用的可行性,为太赫兹高速探测与高频通信领域的集成跨阻放大提供了一种有效技术手段。