Terahertz Phase Image Reconstruction Using an Iterative Algorithm

We present a terahertz phase contrast imaging technique based on the iterative phase retrieval method which can be realized readily on the conventional terahertz intensity measurement system. The complex wave field of terahertz radiation in the object plane (i.e., the terahertz phase image) is reconstructed from its measured Fourier transform magnitude using the Gerchberg-Saxton-Fienup algorithm with a known object support constraint. Preliminary experimental tests for a nearly transparent sample are performed to demonstrate the feasibility of this new imaging concept.