Both the reflection inside a hemisphere solid immersion lens (SIL) and the reflection inside the gap between the SIL and the optical recording medium are considered. The near-field SIL imaging theory for high numerical aperture is developed by using the vector diffraction and thin-film optics. Numerical results show that the spot size, Strehl ratio, and sidelobe intensity have an oscillatory behavior with the change of thickness of the air gap, which results from the interference effect of the transmitted field. We find that for smaller spot size, the Strehl ratio is smaller but the sidelobe intensity is larger. A certain thickness of air gap is useful for optical storage, which is less than 63nm for the system in the simulated examples.
© 2006 Optical Society of America
Original Manuscript: September 12, 2005
Revised Manuscript: December 25, 2005
Manuscript Accepted: December 27, 2005
Yaoju Zhang, "Theoretical study of near-field optical storage with a solid immersion lens," J. Opt. Soc. Am. A 23, 2132-2136 (2006)