太赫兹光热电探测器读出方法

Readout method of terahertz photothermoelectric detectors

摘要:

太赫兹光热电探测器基于热生载流子在温度梯度驱使下迁移的原理实现太赫兹波探测，具有快响应、超宽带、自供电、室温工作及结构简单等优势，受到广泛关注。目前，探测器读出主要采用调制-解调方法，通过电流放大器与锁相放大器级联实现测量，集成度低，成本高，难以实现阵列读出。为满足光谱测量、成像感知等应用需求，本文对光热电阵列探测器单元读出方法进行研究。从探测器机理出发，对输出信号进行建模分析；在此基础上设计板级专用读出电路，实现前置放大与锁相放大功能。测试表明，该方法可以在强噪声背景环境下对太赫兹光热电探测器进行高精确度读出，增益达到140.7 dB，信噪比改善了38.3 dB。

Abstract:

Terahertz photothermoelectric detectors are based on the principle of thermogenerated carriers migrating under the influence of a temperature gradient to achieve terahertz wave detection. They have advantages such as fast response, ultra-wideband, self-powered, room temperature operation, and simple structure, which have attracted widespread attention. Currently, the readout of detectors mainly adopts a modulation-demodulation method, realized by cascading a current amplifier with a lock-in amplifier for measurement, which has low integration, high cost, and is difficult to achieve array readout. To meet the application requirements of spectral measurement and imaging perception, this paper studies the readout method of the photothermoelectric array detector unit. Starting from the detector mechanism, the output signal is modeled and analyzed; based on this, a board-level dedicated readout circuit is designed to achieve front-end amplification and lock-in amplification functions. Tests show that this method can achieve high-precision readout of terahertz photothermoelectric detectors in a strong noise background environment, with a gain of 140.7 dB, and the signal-to-noise ratio is improved by 38.3 dB.