Design Analysis of a Beam Splitter Based on the Frustrated Total Internal Reflection

Abstract

Abstract-In this work, a theoretical analysis on the design of the beam splitter (BS) based on the frustrated total internal reflection (FTIR) is made. We consider a model structure made of a lowindex gap layer bounded by two high-index layers. In the design of a 50/50 BS, we find that there exists a critical gap thickness which is a decreasing function of the angle of incidence for both T E and T M waves. There also exists a critical wavelength for the incident wave, and it increases with increasing angle of incidence. Finally, at a fixed gap thickness and wavelength of incident wave, the critical angle in T E wave is slightly larger than that of T M wave. The analysis provides some fundamental information that is of particular use to the design of a BS within the framework of FTIR.