NIST expands UV optical material characterization facility. (General Developments).

NIST has completed a series of measurements to determine the damage threshold and lifetime of optical materials under intense ultraviolet (UV) radiation produced by excimer lasers. Using a capability developed by a NIST scientist and NIST guest researcher, the integrated energy density (or dose) necessary to cause catastrophic damage of selected UV materials was determined.

These studies, part of an on-going program to develop a primary standard for 157 nm excimer laser power and energy measurements, represent the first quantitative damage studies of UV optical materials for use with excimer lasers. Long-term exposure studies were carried out in cooperation with MIT Lincoln Laboratory to simulate typical calorimeter operating conditions.

The damage measurements were performed using a beamsplitter-based calibration system in which a spatially uniform beam from an ArF excimer laser is generated using a special beam homogenizer. The beam profiles were recorded and characterized to determine the integrated dose at the sample plane. Measurement trace- ability for these measurements stems from an electrically calibrated, primary standard calorimeter developed by NIST scientists.

CONTACT: Marla Dowell, [phone]; [e-mail].