Tolerance Analysis of Near-Field Optical Recording System

The near-field optical recording using solid immersion lens(SIL) is evolving as a promising technology towards high-density optical recording [1-5]. The high-density recording is achieved by introducing a high-index Solid Immersion Lens in between the recording medium and the objective lens, there by increasing the numerical aperture of the optical system. Birukawa et al[5] has analyzed the effect of deviation in SIL height and decenter on the focused beam spot position. However, the deviation from the ideal relative position of the SIL and the objective lens is a practical problem, which can cause serious wavefront aberration, and this will greatly affect the beam spot quality. In this paper, we analyze the aberration introduced due to lateral and longitudinal misalignment of the Supersphere Solid Immersion Lens (SSIL) with respect to the objective lens based on the wavefront aberration. The optical coupling efficiency of the SSIL lens to the recording layer is also analyzed.