STTR PHASE I: Electro-Optic Field Sensors for Far-Infrared Imaging Applications

*9632181斯图尔特我们计划研究和开发一种基于超宽带电场传感器的成像系统。该装置将基于一种新的光电设计，能够在从近直流到几太赫兹的频率范围内进行时间域远红外光谱。基本上，电场传感器系统是基于电光晶体中的线性电光效应(Pockel效应)，其中脉冲微波信号充当瞬时偏置，在传感器晶体中诱导瞬时偏振。然后用同步脉冲激光探测这种偏振，激光将空间和时间上的电场分布投射到一台CCD摄像机上。我们之前对这些成像传感器的研究表明，这些成像传感器具有亚波长空间分辨率、飞秒时间分辨率、近DC-THz带宽、亚mV/cm场灵敏度、高达100 Hz的扫描速率和优于10,000：1的信噪比。电光探测器具有平坦(非共振)光谱响应率(从近DC到几个THz)、大探测器面积(1 Cm2)和扩展的动态范围(1,000,000)。该系统结构简单、光学并行处理能力强、信噪比高，适合于实时、二维相干远红外成像应用。***

*** 9632181 Stewart We propose to investigate and develop an imaging system based on ultra-wideband electric-field sensors. The proposed device will be based on a new optoelectronic design which is capable of timedomain far-infrared spectroscopy across a frequency range extending from near DC to several THz. Fundamentally, the electric-field sensor system is based on the linear electro-optic effect (Pockel's effect) in electro-optic crystals where a pulsed microwave signal acts as a transient bias to induce a transient polarization in the sensor crystal. This polarization is then probed by a synchronously pulsed laser beam, and the spatial and temporal electric-field distribution is projected onto a CCD camera by the laser. Our previous studies of these imaging sensors has demonstrated a sub-wavelength spatial resolution, femtosecond temporal resolution, near DC-THz bandwidth, sub-mV/cm field sensitivity, up to 100 Hz scan rate, and a signal-to-noise ratio better than 10,000:1. The electro-optic detection has a flat (nonresonant) spectral responsivity (from near DC to several THz), a large detector area ( 1 cm2), and an extended dynamic range ( 1,000,000). The simplicity of the detection geometry, capability for optical parallel processing, and excellent signal-to-noise ratio make this system suitable for real-time, 2-D coherent far infrared imaging applications. ***