The Nature of the Coupling Field in Optical Data Storage Using Solid Immersion Lenses

Abstract

The field incident onto the interface between the solid immersion lens (SIL) and recording medium is decomposed into two parts that exhibit different behavior as the beam propagates through the recording layers. The homogeneous part is shown to diffract, and the inhomogeneous part decays exponentially away from the bottom of the SIL. Reflection and signal contrast are calculated for a phase-change recording medium. The dependences of the signal contrast on the gap width, the refractive index of gap and the SIL are analyzed.