LIGHT CONVERGING OPTICAL SYSTEM AND METHOD FOR REDUCING POLARIZATION ROTATION

摘要

PROBLEM TO BE SOLVED: To provide a light converging optical system capable of reducing polarization rotation with no increase or a minimum increase in weight and also provide a method for reducing the polarization rotation. SOLUTION: The light converging optical system (20) includes an objective lens (21) converging a laser light with a high NA and launches the laser light converged by the objective lens (21) into the surface (23a) of a disk. The surface of the objective lens (21) is coated with a multilayer film, and a polarization rotation in the direction opposite to the polarization rotation generated on the surface (23a) of the disk is generated in all parts or a part of the pupil of the eye. As a result of it, the polarization rotation generated when the laser light is made incident to the surface (23a) of the disk is reduced by the polarization rotation generated in the objective lens (21).