DIFFRACTION OPTICAL ELEMENT AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To improve diffraction efficiency and to obtain a diffraction optical element having optical performance applicable to a short wavelength light source of UV rays, etc. SOLUTION: Alumina thin films 3 and quartz thin films 4 are previously alternately deposited by about 62 nm each on the surface of a quartz substrate 2 to a thickness of about 0.43 μm in total by using a sputtering vapor deposition method. The vapor deposited thin films on the quartz substrate 2 are etched by using a dry etching(RIE) method with the resist patterns formed by printing the patterns of a chromium mask in reduction on the photoresist on a binary optic(BO) substrate by using a stepper for an (i) line of γ=365 nm and developing these resist patterns as an etching mask, by which a BO lens 1 is formed.