UNI-TRAVELLING CARRIER PHOTOMIXERS FOR THZ DETECTION

虽然太赫兹（THz）（每秒一千亿次振荡）在成像、传感和安全等应用方面显示出越来越大的潜力，但测量这种信号的技术解决方案的数量有限。此外，探测器，如戈莱电池和光声电池不能检测太赫兹功率的快速调制。该计划建议研究使用通常用于探测光的半导体设备探测太赫兹范围内振荡的电磁波的可能性。这种类型的设备对太赫兹探测很感兴趣，主要有三个原因；首先，作为一种半导体器件，它结构紧凑，成本效益相对较低；其次，它在室温下工作，而大多数其他太赫兹探测技术必须在非常低的温度下工作；第三，它已经被证明是高效的亚赫兹发射器。这项工作将集中于调查这样一个事实，即在感兴趣的半导体器件中，光探测结果载流子的速度强烈依赖于施加在器件上的电场。这种差异意味着，如果设备接收到天线产生的电场（待检测的太赫兹信号），它将影响其检测入射光信号快速变化的方式。这样的效应会导致产生频率低得多的中频输出，可以使用标准的电子测量设备进行分析。在计划结束时，预计制造的装置将能够用于室温下工作的太赫兹扫描系统。

Although terahertz (THz) (a thousand billion oscillations in a second) show growing potential for applications such as imaging, sensing and security, the number of technological solutions to measure such signals is limited. Further, detectors such as Golay cells and photo-acoustic cells cannot detect fast modulation of the THz power. This programme proposes to investigate the possibility of detecting electromagnetic waves that oscillate in the THz range using a semiconductor device that is normally used to detect light. This type of device is of interest for THz detection for three main reasons; first, as a semiconductor device it is compact and relatively cost effective, second, it operates at room temperature while most other THz detection technologies must be operated at very low temperatures and third, it has already proven to be efficient as aTHz emitter. The work will concentrate on investigating the fact that in the semiconductor device of interest the velocity of the carriers that are the result of light detection is strongly dependent on the electric field that is applied to the device. Such a difference implies that if the device receives an electric field generated by an antenna (the THz signal to be detected) it will affect the way it detect fast changes in an incoming light signal. Such an effect can result in the creation of an intermediate frequency output at a much lower frequency, that can be analysed using standard electronic measurement equipment. At the end of the programme it is expected that a fabricated device will be able to be used in a THz scanning system operating at room temperature.