摘要
本文选用相同光电响应灵敏度的高性能PIN光电二极管,将探测激光信号转换为电流信号,再通过低噪声电流-电压转换将电流信号转换为电压信号,通过采用具有很强共模信号抑制能力的差分放大器,不仅极大地抑制了太赫兹信号本身携带的噪声,也避免了探测激光强度扰动引起的测量误差.差分最后经过带通滤波器控制工作带宽和进行降噪处理,经由主放大器实现太赫兹信号输出.实验表明,该探测器具有高灵敏度、高信噪比、宽工作带宽等显著特点,完全满足了太赫兹时域光谱系统研究的需要.
An electro-optic terahertz（THz） detector with a newly-designed circuit was investigated.A pair of high-quality PIN photodiodes and a low-noise current-voltage conversion circuit were applied to convert the modulated probe laser to voltage signal.These two voltage signals were subsequently sent to a specially-designed differential amplifier with high common-mode-rejection-rate（CMRR） that largely restrain the noise of terahertz signal and avoid the disturbance of probe laser intensity.Then a band-pass filter was employed to control bandwidth and restrain noise of the detected signal.Finally,the weak THz signal was detected via a main amplifier.Experimental results show that the THz detector has high signal-to-noise-ratio（SNR）,teeny distortion and wide bandwidth,which fully satisfy the requirement of terahertz time-domain spectroscopy（THz-TDS）.
出处
《电子学报》
EI
CAS
CSCD
北大核心
2012年第9期1705-1709,共5页
Acta Electronica Sinica
基金
国家高技术研究发展计划(863计划)项目(No.2011AAxxx2008A)
中国科学院百人计划基金项目(No.J08-029)
中国科学院知识创新工程重要方向性项目(No.YYYJ-1123-4)
国家重点基础研究发展计划(973计划)项目(No.2007CB310405)
关键词
太赫兹波
电光探测
信噪比
灵敏度
太赫兹时域光谱
terahertz（THz）
electro-optic detection
signal-to-noise-ratio（SNR）
sensitivity
terahertz time-domain spectroscopy（THz-TDS）
