Thickness tolerance compensation of SIL first surface near-field recording with replicated lens on SIL

In this paper, we propose a novel optics design for improving the thickness tolerance of a super-hemispherical solid immersion lens (SIL) that is usually used in near-field recording for high data density. To obtain the improved thickness tolerance of a SIL and a high numerical aperture simultaneously, an aspheric replicated lens is added on the SIL. Using an additional aspheric replicated lens, spherical aberration which induces the tight thickness tolerance of the SIL is effectively reduced, therefore it was able to improve the thickness tolerance of the SIL, maintaining high NA equal to that of super-hemispherical SIL. In addition, in this paper, other various tolerances such as decenter and tilt are considered to make sure of the possibility of fabrication.