Importance

Loading Importance Indicators...

Abstract

A method of selecting suitable laser-stable optical material for making an optical element, especially for transmission at wavelengths under 200 nm, is described. It includes a first pre-irradiation to produce radiation damage, subsequent excitation of induced fluorescence with light at between 350 to 700 nm at least ten minutes after the first pre-irradiation and measurement of induced fluorescence intensities at one or more wavelengths between 550 nm and 810 nm. After the fluorescence intensity measurement a second pre-irradiation is performed with an at least 1000-fold higher energy than in the first pre-irradiation and then induced fluorescence intensities are again measured to determine the increase in the fluorescence intensities. The materials determined to have suitable laser stability are used for making lenses, prisms, light-conducting rods, optical windows and optical devices for DUV lithography, especially steppers and excimer lasers, integrated circuits, computer chips as well as other electronic devices.

Loading the Abstract Image...

First Claim