Scanning Laser Two-Dimensional Terahertz Emission Imaging System

Abstract

We have proposed and developed a scanning laser two-dimensional (2D) terahertz (THz) emission imaging system for high-spatial resolution and high-speed measurement. To obtain 2D THz images of the sample, laser pulses are scanned over a 2D THz emitter plate by a galvano meter. In this system, THz wave pulses are locally generated at the laser irradiation spot and transmit through the sample displaced on the emitter. The amplitude of the transmitted THz wave pulse is detected by using a typical THz time-domain spectroscopic technique. Using this system, we have succeeded in obtaining THz transmission images of various samples with a spatial resolution of sub-wavelength order up to 27 μm at an imaging speed of about 47 seconds/image for 512 × 512 pixels. We also investigated the application of the system with metamaterial samples, and observed resonant frequency shifts in transmission spectra. This paper presents a review on the fabricated system.