基于光子混频的可调谐连续太赫兹波辐射系统

Tunable Continuous-Wave Terahertz Radiation System Based on Photomixing

基于光子混频原理及相干探测技术,利用外腔半导体激光器及一种蝶形交指结构低温砷化镓光电导天线,搭建了一个可调谐连续太赫兹波辐射探测系统。在室温条件下,实现了连续太赫兹波的产生及探测,其连续太赫兹波输出的线宽优于1 MHz。在频率小于0.70THz时,实验获得的系统信噪比均在50dB以上。在频率为0.50THz处,系统信噪比为64dB。另外,还实验研究了辐射太赫兹波电场强度与光电导天线偏置电场的关系,讨论了外腔半导体激光器模式对连续太赫兹波辐射的影响。

A room-temperature-operation tunable continuous-wave terahertz （THz） radiation and detection system, which consists of two external cavity semiconductor lasers and an interdigited finger bow-tie antenna on low temperature GaAs substrate, is established based on photomixing and coherent detection technology. The generation and detection of continuous-wave THz wave are realized, and the spectral purity of system is better than 1 MHz. The signal-to-noise ratio （SNR） of the system is better than 50 dB with frequency below 0.70 THz, and the maximum SNR of 64 dB is achieved at 0.50 THz. In addition, the relation between the electric field intensity of the radiated terahertz wave and the biased electrical field for the photoconductive antenna is experimentally given, and the impact of multi-longitudinal mode operation of the external cavity semiconductor laser on continuous-wave THz radiation is discussed.