Development of Tera-Hertz Detector with extended over 1 digit frequency range

研制了一种新型宽带、高速、高灵敏度的太赫兹探测器。该探测器原型由抛物柱面反射镜、长线天线和肖特基势垒二极管组成。直接探测测量表明，对于1-2太赫兹，没有任何调整，灵敏度稳定在150±50V/W。将长线天线固定在抛物面柱面反射镜的焦点上，实现了操作步骤少，易于与外部太赫兹信号耦合，大大提高了系统的实用性。光学抛光反射镜和磨砂反射镜具有相当的灵敏度，因此该系统可以实现简单的抛光和低成本的反射镜制造。辐射方向图的最大辐射角约为23°，主瓣占主导地位，这归因于线天线的特性，证实了与经典天线理论的良好一致性。在CO2激光泵浦的2.0 mW太赫兹激光光源下，系统在5.2和6.3 THz处的灵敏度约为3.0V/W。这些性能至少达到了SBD与长线细天线相结合所观测到的先前记录的20倍以上。新开发的系统将在高速/宽带太赫兹光谱应用中发挥重要作用。最大偏差为2.5 mm的磨光镜没有灵敏度退化，抛物面镜易抛光，成本低，适用于该系统。

A new, wide-band, high-speed and high-sensitivity THz detector has been developed. The prototype detector consists of a parabolic cylindrical mirror, a long wire antenna and a Schottky barrier diode. Direct detection measurements have shown a stable sensitivity of 150 ± 50 V/W for 1-2 THz without any adjustments. The long wire antenna was fixed at the focus of parabolic cylindrical mirror then it has been realized less operation steps, easy coupling to the external THz signals and a dramatic enhancement in the practicality of this system. The optically polished mirror and frosted surface one showed comparable sensitivities, thus easy polishing and less cost mirror fabrication can be applied for this system. The radiation pattern showed a maximum radiation angle of approximately 23° with its dominant main lobe, which was attributed to the wire antenna character and confirmed good agreements with classical antenna theory.System sensitivities of about 3.0 V/W at 5.2 and 6.3 THz were also observed by using 2.0 mW THz-laser sources pumped by CO2 laser. These performances have reached at least more than 20 times values of previous records observed by SBD coupled with a long-wire thin antenna. Newly developed system will be much useful for the high-speed/wide band THz-spectroscopy applications. The frosted surface mirror with maximum deviation of 2.5 mm showed no sensitivity degradations, thus easy polishing, less cost, parabolic mirror is applicable in this system.