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

研制了一种新型的宽带、高速、高灵敏度太赫兹探测器。原型探测器由一个抛物面柱面反射镜、一个长线天线和一个肖特基势垒二极管组成。直接检测测量表明，在1-2太赫兹下，无需任何调整，灵敏度稳定在150±50 V/W。将长丝天线固定在抛物面柱面镜的焦点处，实现了操作步骤少、与外界太赫兹信号耦合方便、系统实用性大大提高的特点。光学抛光镜与磨砂表面镜具有相当的灵敏度，因此该系统可以采用简单的抛光和较低的制造成本。辐射方向图显示出以主瓣为主导的最大辐射角约为23°，这归因于线天线的特性，与经典天线理论相吻合。采用CO2激光器泵浦的2.0 mW太赫兹激光源，在5.2和6.3太赫兹下，系统灵敏度约为3.0 V/W。这些性能至少达到了SBD与长线细天线耦合观察到的先前记录的20倍以上。新研制的系统对高速/宽带太赫兹光谱的应用具有重要意义。最大偏差为2.5 mm的磨砂面镜灵敏度无下降，抛光方便，成本低，抛物面镜适用于该系统。

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.