Optical design for translation of THz medical imaging technology

This paper presents novel a first pass on the thorough analysis of THz optical designs intended for image acquisition of burn wounds in animal models. Current THz medical imaging research typically employs and fixed source detector architecture coupled by a train of off-axis parabolic mirrors. When used individually, parabolic mirrors have near diffraction limited focusing properties, extremely low loss, and are dispersion free. However, when a combination or train of multiple parabolic mirrors are utilized geometric errors can be generated early in the train and exacerbated as the beam propagates to the detector. These errors manifest as significant increases in spot size, asymmetries about the optical axis in beam irradiance and polarization, and the generation of cross polarization components. This work presents a novel configuration of off-axis parabolic mirrors designed to maximize the practicality of beam alignment and image acquisition. Quasi-physical optics simulations of the optical performance are described and significant perturbations in polarization symmetry were observed. The configuration can be described as in between two canonical parabolic mirror configurations. The performance of three different pairs of off-axis parabolic mirror pairs coupled to the novel configuration are presented herein.