Effect of interface gradient on the optical properties of multilayered porous silicon photonic structures

Abstract

The effect of gradually varying refractive index at each interface of a multilayered porous silicon photonic structure is studied experimentally and theoretically. The variation of refractive index at the interface, between any two consecutive layers, is done in small ladder-like steps (increasing/decreasing) and the resulting optical properties are compared with the standard structures with the flat interface and similar optical thickness. The proposed structures are proved to be useful in reducing the stress between the layers of high contrast, resulting in the mechanically more stable structures.