# BROADBAND TUNABLE EXCIMER LASER STUDIES

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 Title: BROADBAND TUNABLE EXCIMER LASER STUDIES ZHU, YUNPING The principal purpose of this work has been the studies of the broadband tunable excimer laser namely XeF(C $\to$ A). Wideband tunability of this excimer laser was first demonstrated with a simple compact dispersive stable cavity in a transverse e-beam pumped geometry. More recently, a series of experiments has been performed to control the XeF(C $\to$ A) by dye laser injection. In any low-gain, short-pulse laser systems, rapid build-up of the optical field within the resonator is critical to good laser performance and extraction efficiency. Simultaneous injection of a "seed" signal into the cavity with laser pumping excitation can create a much faster increase in the intensity of the optical field. This rapid build-up of the optical field will aid the competition against radiative emission from the high gain XeF(B $\to$ X) transition and non-radiative quenching of the XeF excimers by halogen donors and other constituents of the laser gas mixture. Efficient, ultranarrow (0.002 nm to 0.005 nm) spectral output from an electron-beam excited XeF(C $\to$ A) laser medium (Ar/Kr/Xe/F$\sb{2}$/NF$\sb{3}$ mixture) has been observed by injection tuning. Amplification of an injected tunable dye laser pulse was achieved throughout the entire blue-green spectral region from 435 nm to 535 nm. Several different confocal unstable resonator geometries with magnification of 1.05 to 1.23 were investigated. A maximum output of about 85 mJ was measured at 482.5 nm for a cavity with magnification M = 1.1, which corresponds to an energy density and intrinsic efficiency of 4.7 J/liter and $\sp\sim$5%, respectively. These values are comparable to those of UV rare gas-halide lasers. In order to gain a better understanding of the injection control process in XeF(C $\to$ A) laser, a semiempirical model using a pulsed regenerative amplifier approach has been established with good accuracy. A set of coupled rate equations are used for this purpose. Some key factors in cavity and pumping source design are addressed. ZHU, YUNPING. (1987) "BROADBAND TUNABLE EXCIMER LASER STUDIES." Doctoral Thesis, Rice University. http://hdl.handle.net/1911/16118. http://hdl.handle.net/1911/16118 1987