H. Pummer

Picosecond, tunable ArF* excimer laser source

A 40‐mJ ArF* laser with pulse duration ∼10 ps and spatial and spectral properties close to the transform limits is described. Substantial extraction of the available energy from the final amplifier is demonstrated, a fact providing direct evidence against the presence of significant nonlinear losses in the amplifying medium up to an intensity of ∼1 GW/cm.2

Generation of extreme ultraviolet radiation at 79 nm by sum frequency mixing

High brightness tunable coherent extreme ultraviolet (XUV) radiation at 79 nm with a peak power of ∼200 mW has been generated in H 2 gas by sum frequency mixing of two quanta from a high spectral brightness ArF* (193 nm) source with one quantum from a tunable dye laser (∼436 nm). Spectroscopic application of this radiation has been demonstrated by observation of a broad (∼160 cm-1) autoionizing structure in Ar and narrow (∼2 cm-1) autoionizing features in D 2 . An analysis is given which identifies the dominant molecular states involved in the nonlinear susceptibility of the medium (H 2 ). The frequency independent tuning behavior of the 79 nm output power observed over ∼300 cm-1is related to the molecular structure and response of the nonlinear medium in the intense optical field.

Tunable, ultrahigh-spectral-brightness ArF* excimer laser source

An extremely high spectral-brightness ArF* 193-nm excimer source with the following output pulse characteristics is described: approx.30-mJ pulse energy, approx.5-nsec pulse duration, spectral width less than 260 MHz, absolute frequency control to within 1.8 GHz, approx.5 x 15-..mu..rad beam divergence, and repetition rate up to 10 Hz. Within the uncertainty of measurement, the spectral width of the output radiation is Fourier transform limited and the beam divergence corresponds to the diffraction limit of the radiating aperture.