A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear reflectanceversus- angle-of-incidence response over a certain range of angles. Linearization at and near normal incidence is a special case that leads to a maximally flat response for p-polarized, s-polarized, or unpolarized light. For midrange and high-range linearization with moderate and high slopes, respectively, the best results are obtained when the incident light is s polarized. Application to a Si substrate that is coated with a SiO2 film leads to novel passive and active reflection rotation sensors. Experimental results and an error analysis of this rotation sensor are presented.
Journal of the Optical Society of America A
R. M. A. Azzam, M. M. K. Howlader, and T. Y. Georgiou, "Single-layer-coated surfaces with linearized reflectance versus angle of incidence: application to passive and active silicon rotation sensors," J. Opt. Soc. Am. A 12, 1790-1798 (1995)