The Surface-Roughness Effects on Light Beam Interactions between the CsI Phosphor and Optical Sensing Materials

Abstract

In digital phosphor-based imaging modalities, one important intermediate stage is the optical coupling between the phosphor material and the optical sensor. The performance of the optical compatibility is affected by surface-roughness issues, for which further research should be paid. This paper investigates the surface-roughness influence between the CsI phosphor material and the optical sensing materials (i.e., the silicon dioxide—SiO2, the indium tin oxide—ITO, and the indium gallium arsenide—InGaAs) employed in several image devices. Results showed that for all sensing materials, the transmission factor t of the optical signal follows qualitatively the variation of their refractive indexes and quantitatively the variation of the surface roughness and the incident polar angle. Finally, with respect to light wavelength, the curve of variation was found to be continuous for ITO and SiO2 sensing materials; however, lower and sharper variations were observed in the first case.