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

研制了一种新型的宽带、高速、高灵敏度的太赫兹探测器。原型探测器由抛物柱面镜、长线天线和肖特基势垒二极管组成。直接探测测量表明，在1-2 THz范围内，无需任何调整，灵敏度稳定在150 ± 50 V/W。将长线天线固定在抛物柱面镜的焦点处，实现了操作步骤少，易于与外界THz信号耦合，大大增强了系统的实用性。光学抛光的反射镜和磨砂表面的反射镜显示出相当的灵敏度，因此容易抛光和较低的成本反射镜制造可以应用于该系统。在5.2和6.3THz波段，利用CO2激光泵浦的2.0mW太赫兹激光源，系统灵敏度分别为3.0V/W左右。这些性能至少达到了与长线细天线耦合的SBD所观察到的先前记录的20倍以上的值。新开发的系统将是非常有用的高速/宽带太赫兹光谱应用。磨砂镜面最大偏差为2.5mm，不影响灵敏度，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.