In-Situ Polarimetric Calibration of Broadband Terahertz Imaging Systems with and Uncharacterized Imperfect Wire Grid Polarizer

With the recent advances in terahertz time-domain instruments, the design of handheld scanners has drawn significant attention. Recently, we developed a polarimetric version of our Portable HAndheld Spectral Reflection (PHASR) Scanner and introduced the in-situ calibration of the scanner using a rotating wire grid polarizer. However, the wire grid polarizers are far from ideal, due to their leaky spectral performance. In this work, we propose a new approach to simultaneously characterize both the scanner, and the imperfect wire grid polarizer used for calibration measurements to improve the characterization of the handheld device. In addition, the effect of the choice of rotation angles of the polarizer will be discussed using matrix condition number minimization analysis.