DIFFRACTION OPTICAL ELEMENT AND ITS FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To efficiently provide a practicable diffraction optical element at a low cost. SOLUTION: The refractive index modulation type diffraction optical element includes translucent films (2) of silicon or a silicon compound formed on a translucent substrate (1). The translucent films (2) include diffraction gratings alternately arranged with local regions (2a) of relatively high refractive indices and local regions (2) of relatively low refractive indices. Refractive index differences greater than 5% exist between the high-refractive index regions (2a) and the low-refractive index regions (2). Such refractive index differences can be easily formed by irradiating the translucent films (2) of the silicon or the silicon compound with an energy beam (4). COPYRIGHT: (C)2004,JPO&NCIPI