Utilization of Thin-film to Control Total Phase Shift during Total-internal-reflection

This paper analytically describes the concept of controlling total phase shifts accompanying the propagation of p- and s-polarized light at the interface between two transparent dielectric media. This has been achieved by introducing a thin-film of specific refractive index and thickness. Generalized expression for the phase shifts have been formularized. Computer aided analysis has been carried out using isotropic semiconductor slab coated with different thin-films.

I. Introduction

When the rays of monochromatic light passes from a rarer medium to a denser medium, it bends towards the normal to the plane of incidence but conversely when light rays transmit from a denser medium to a rarer medium, it bends away from the normal. This cognition leads to the theory of Total-internal-reflection (TIR), i.e., the transmitted or the refracted rays of monochromatic light bends beyond 90 degrees away from the normal of the planner interface and back to the incident medium. At this instant no transmission or refraction takes place. The factor liable to this TIR is the refractive indices of the involving media. The angle of incidence beyond which the rays of light gets totally reflected back from the planner interface to the incident medium is called the critical angle . To signify the geometric orientation of the oscillations of a transverse plane monochromatic wave, the concept of polarization comes into the picture. However, the incident, monochromatic light has two segments that are polarized with the electric vector vibrating parallel (p) and perpendicular (s) to the plane of incidence and experiences different Fresnel reflection and transmission coefficients [1].