A tunable, ultrahigh spectral brightness KrF* excimer laser source

Abstract

An extremely high spectral brightness KrF* (248 nm) excimer source is described. This instrument combines the property of continuous tunability over the full gain profile with the following output pulse characteristics: pulse energy ∼60 mJ, pulse duration ∼10 nsec, spectral width 15030 MHz, absolute frequency control to within 300 MHz, and beam divergence ∼50 μrad. Within the uncertainty of measurement, the spectral width of the output radiation is Fourier transform limited, and the beam divergence corresponds to the diffraction of the radiating aperture.