Broadband THz Edge-Enhanced Imaging Technology Based on Electro-Optic Sampling

Abstract

Based on the radial Hilbert transform of spatial filtering and electro-optical sampling, we propose a broadband terahertz edge-enhanced imaging method in this work. Instead of using a narrow-band THz vortex phase plate, here we use vortex ultrashort laser pulse to realize the THz enhancement imaging which can be applied for few-cycle THz imaging. The principle of edge enhancement is analyzed theoretically, and the analytical expression of the final terahertz imaging is derived. We found that edge-enhancement imaging corresponds to the nonlinear term of the THz field, and the background and linear terms can be suppressed when the static birefringent phase is set to zero. The simulations show that our method can effectively improve the contrast and signal-to-noise ratio of terahertz imaging.