REFLECTIVE DIFFRACTION GRATING

摘要

PROBLEM TO BE SOLVED: To eliminate need of adding a special optical element for the purpose of reducing polarizing characteristic in an optical system using a diffraction optical element, by decreasing polarization dependency of a reflective diffraction grating. SOLUTION: The reflective diffraction grating is one in which a plurality of parallel linear grooves are formed on the surface of a tabular substrate at regular periods. The protrusions between the grooves are designed to have two alternately different kinds of heights, with the protrusions of each height arrayed with a period in the range of 0.1-10 times average wavelength in a spectral wavelength region. It is desirable that the first height of this inter-groove projections is in the range of 1/5-1/2 of the average wavelength in the spectral wavelength region of the diffraction grating and that the second height is in the range of 1/100-1/10 of the same average wavelength. COPYRIGHT: (C)2004,JPO&NCIPI