Terahertz Imaging With a Time-Reversed Finite Difference Time-Domain Method

A novel approach to three-dimensional terahertz (THz) imaging based on a time-reversed finite difference time-domain (FDTD) method is presented. Time-reversed convolutional perfectly matching layers (CPML) were implemented as boundaries to truncate the simulation domain. The proposed computationally efficient technique is capable of producing detailed images using a much smaller set of measured data compared to conventional terahertz imaging methods. A coarser grid of transmitter/receiver locations is needed, saving significant data acquisition time. Transmission and reflection imaging configurations in far-field were investigated. Simulations as well as experimental results, including comparisons with conventional methods, are presented. Our approach was validated experimentally using a time-domain terahertz measurement system.