Passive terahertz synthetic aperture imaging using optical processing method

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.