DIFFRACTION OPTICAL ELEMENT AND ITS FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a practical diffraction optical element efficiently and inexpensively. SOLUTION: The refractive index modulation type diffraction optical element includes a light translucent DLC (diamond-like carbon) film 2 formed on a light translucent substrate 1. The DLC film 2 includes diffraction gratings containing a local region 2a of relatively high refractive index and a local region 2b of relatively low refractive index. The DLC film 2 can be easily deposited on the substrate 1 by plasma CVD (chemical vapor deposition) and the local region 2a of relatively high refractive index in the DLC film can easily be formed by being irradiated with energy beams 4 such as ion beams. COPYRIGHT: (C)2004,JPO