Experimental verification of autoalignment for focusing unit of near field recording system: Neural network approach

Abstract

From the viewpoint of assembly, an autoalignment method and experimental verification results for the focusing unit (FU) of a near-field recording (NFR) system are proposed. Generally, the size of focusing unit composed of an objective lens and a solid immersion lens is smaller than that of the conventional focusing unit. Hence there are difficulties in the precise assembly of the small focusing unit. We composed an autoalignment system with an interferometer and carried out an experimental verification of the proposed methodology using some focusing unit samples. Excluding manufacturing errors of optical components, we could make the alignment error of FU less than wavefront error of 0.03 lambda by the proposed method.