Design of Compatible Optics for Solid-Immersion-Lens-Based Near-Field Recording System and Blu-ray Disc Using Relay Lens

Abstract

We designed compatible optics for a solid-immersion-lens (SIL)-based near-field recording (NFR) system and a Blu-ray disc (BD). The working distance, numerical aperture (NA), and cover layer thickness of the SIL-based NFR system differ from those of BD. Therefore, for the compatibility of a cover layer incident type NFR system of whose NA is 1.46 and BD, we use a relay lens that is composed of two low-NA lenses. The optical tolerances such as decenter, tilt, and SIL thickness tolerances are considered to ensure manufacturability. The decenter and tilt tolerances of each optical component are greater than 1.0 µm and 0.1°, respectively. The tolerance of the SIL thickness range is 14 µm at the criterion of the wavefront aberration of 0.035 λrms. We design the optical layout and simulate each focus error signal of BD and the SIL-based NFR system. From the practical design results, we confirm that the SIL-based NFR system can be compatible to BD with a simple relay lens.