Fabrication of a Hemi-Paraboloidal Solid Immersion Mirror and Designing of an Optical Head with the Mirror

Abstract

A hemi-paraboloidal solid immersion mirror (HP-SIM) was for the first time fabricated with the electrolytic in-process dressing (ELID) grinding technology. By improving the surface deviation and roughness of the HP-SIM to the order of ±0.3 µm and 4 nm, the spot size (FWHM) of 0.22×0.26 µm was obtained in the blue light concentration with the HP-SIM though fairly large side lobes were observed. A small-sized optical head was also designed with the HP-SIM, a pair of collimating lenses, and laser diode, which height can be reduced to 1 mm. Diffraction limited concentration is expected with the HP-SIM optical head, though the accuracy of less than ±1 µm is required for the alignment of the LD to the collimating lenses for both X and Y directions.