Development of distributed feedback dye lasers for generation of high-power 193 nm excimer laser short pulses

The combination of picosecond dye lasers, nonlinear mixing in crystals and excimer amplifiers offers an attractive way to generate intense diffraction-limited pulses throughout the ultraviolet region. However it is difficult to generate 193 nm seed pulses because this wavelength cannot be obtained by second harmonic generation method in any known crystals.; The thesis will describe a laser system which efficiently generates short, relatively stable high power 193 nm pulses. A new type of distributed feedback dye laser which has a grating on a thin substrate was also developed. It is reliable and easy to use. Two such DFDLs are used in the laser system to generate 10 ps pulses at two selected wavelengths of 266 nm and 706 nm that are frequency up-converted in a BBO crystal to generate nearly transform-limited 193 nm seed pulse about 10 ps in duration. The entire cascading dye laser system is pumped by a 350 mJ, 15 ns pulse at 308 nm generated by a XeCl excimer laser. The 193 nm seed pulse from BBO crystal is amplified in an ArF{dollar}sp*{dollar} excimer laser amplifier to 10 mJ in a nearly diffraction-limited beam. The system routinely produces 193 nm pulses of about 10 picosecond duration which can be focused to intensities of 10{dollar}sp{lcub}14{rcub}{dollar} W/cm{dollar}sp2{dollar}. One application of this system is investigation of the interaction of intense radiation fields with diatomic molecules.; A DFDL model which included non-sinusoidal profile of the modulated gain was developed. The model is used to study theoretically the fluctuation in pulse duration due to the pump variation and intrinsic fluctuation in spontaneous emission which leads the laser pulse.; A two-grating DFDL was also developed, tested experimentally and analyzed theoretically. It allows wavelength tuning and generation of shorter pulses. This type of system should be able to reach the subpicosecond regime with comparable pulse energies and beam divergences by using two-grating DFDL and thin BBO crystal.