采用光学处理方法的被动太赫兹波综合孔径成像

Passive terahertz synthetic aperture imaging using optical processing method

综合孔径技术对于提高被动太赫兹(THz)成像系统的分辨率、减小系统体积有着重要的意义。研究了一种基于电光调制和空间光干涉成像的THz综合孔径成像技术。在该成像方法中,天线阵列接收目标辐射的THz信号,通过混频和电光调制将信号振幅和相位信息加载到激光载波上,由光纤传输该激光信号并在光纤末端形成天线缩比阵列结构,最终利用光纤阵列输出光束的空间互相干在透镜焦平面上获得目标成像。分析了该成像方法的原理,以及成像中的信号变换与光学干涉处理的关键技术,并利用0.5THz超导体-绝缘体-超导体(SIS)接收机进行了电光调制和干涉实验。结果表明:该方法能够应用于被动THz综合孔径成像。

Synthetic aperture imaging technique is valuable for improving the resolution and reducing the system size of passive terahertz （THz） imaging systems. A passive THz synthetic aperture imaging method using electro-optical modulation and optical interference imaging technique was presented. The THz signal of target was received by the antenna array, the amplitude and phase information of the signal were transferred to laser carrier by mixer and optical modulator. The output of the modulators was routed by a fiber. The mimic THz antenna array format was formed at fiber ends. The laser beams emerging from the fiber array formed an image in the focal plane of lens through interference among the optical beams. The principle of this synthetic aperture imaging method and the key technology of signal transform and optical interference processing were analyzed. An electro-optical modulation and interference experiment was carried out using a 0.5 THz Superconductor-Insulator-Superconductor （SIS） receiver. The results show that this method is effective for passive THz synthetic aperture imaging.