Studies of tunable, high power excimer lasers

A detailed investigation of tunable, high power excimer lasers, particularly of the electron-beam pumped XeF(C $\to$ A) laser, is presented. A numerical model is described which simulates the performance of such lasers. The output energy and temporal profile of an injection controlled XeF(C $\to$ A) excimer laser were successfully predicted for a wide range of experimental conditions. The XeF(C $\to$ A) excimer laser was demonstrated as a wideband tunable source of radiation capable of accessing a wavelength range from 455 to 530 nm. A high energy output of 1.2 J per pulse at a repetition rate of 1 Hz was accomplished by the use of a transverse gas flow cell. Injection controlled operation provided a narrow laser linewidth of 0.001 nm and three times diffraction limited spatial beam quality. Stimulated Raman scattering of the XeF(C $\to$ A) laser in hydrogen and liquid nitrogen was used to generate continuously tunable radiation between 525 and 650 nm with pulse energies exceeding 100 mJ. An energy conversion efficiency of 38% and a peak power of 35 MW were achieved. The XeF(C $\to$ A) excimer transition was characterized as a new gain medium for ultrashort pulse amplification. A gain bandwidth of 60 nm, as measured with 100 ps pulses, and a saturation energy density of 50 mJ/cm$\sp2$ for 250 fs pulses constitute a 20-fold improvement over other short pulse excimer laser systems. An ultrahigh power, short pulse amplifier system was designed and built, based on the gain measurements. An unstable resonator, particularly adapted to low gain conditions and high temporal purity was developed for the XeF(C $\to$ A) excimer amplifier. A maximum output energy of 275 mJ was obtained for amplified 250 fs pulses, resulting in terawatt peak power. A spatial beam quality of 2.4 times the diffraction limit was measured, which makes it possible to achieve an intensity of larger than 1 $\cdot$ 10$\sp{19}$ W/cm$\sp2$ in a focused beam. Therefore, the XeF(C $\to$ A) excimer laser amplifier can be used in an exciting new field of studies involving the interaction of ultrahigh intensity light with matter