A study of near field recording optics for cover-layer incident dual-layer disc with an NA=1.45 hemispherical solid immersion lens

Abstract

Practical optics for a cover-layer incident dual-layer disc with an NA=1.45 hemispherical solid immersion lens are designed, using a spherical aberration compensating liquid crystal cell. A hybrid servo system, gap servo for NA >1 and focus servo for NA < 1, is proposed.