Light source for radially polarized light e.g. for optical data storage or confocal microscopy, using strontium-barium-niobate crystal and collimation lens

摘要

The light source uses a strontium-barium-niobate crystal (2) combined with an optical collimation lens (4), the crystal spaced by the focal width infront of the collimation lens along the optical axis of the latter, so that the crystallographic c-axis of the crystal is parallel to the optical axis. The crystal is stimulated by a primary laser beam (1) directed along the optical axis for conical emission of frequency-doubled light (3), converted into a parallel radially polarized light beam (5) by the collimation lens, with blocking of the primary light beam via a light stop.