Experimental Comparison of Terahertz Time-Domain and Frequency Domain Imaging Schemes at 1 THz

Abstract

Terahertz imaging has been established as a standard tool for Nondestructive evaluation (NDE) in recent years. While several studies have been conducted either in Terahertz (THz) time-domain Imaging (TDI) system or a THz CW Imaging (TCWI) system, no direct comparison of performance criteria of these two schemes has been executed systematically to date. In this work, we report the experimental acquisition of an image of a standard USAF Target at a frequency centered around 1 THz with 100 GHz bandwidth. In the resulting comparison, we note that THz TDI produces faster image acquisition with comparatively greater computational analysis and produces images with lower depth of contrast. On the contrary, TCWI records image directly in the frequency domain over a greater acquisition time but with less computational load and provides a higher depth of contrast. We also conclude that in both the schemes the spatial resolution of the image is nominally the same with a similar optical arrangement.