Light Modulation by Reflection

TLDR: In this paper, a computer program was developed to calculate the reflectivity of a medium with a non-uniform dielectric constant, and the results showed that a medium whose ramp extends at least one-third of a wavelength of light into the medium looks homogeneous to the light.

Abstract: The possibility of modulating a light beam by reflecting it from the surface of a crystal whose surface dielectric constant is modulated by an electric field is investigated theoretically. Since the dielectric constant may depend on distance in from the surface of the crystal it was necessary to develop a computer program which calculates the reflectivity of a medium with a non-uniform dielectric constant. To get an idea of the effect of spatial variations in the dielectric constant, the program is first used to calculate the reflectivity of media with simple ramps in their dielectric constant. The results show that a dielectric constant whose ramp extends at least one-third of a wavelength of light into the medium looks homogeneous to the light.