Abstract: A coaxial flashlamp for optical pumping of a tunable dye laser. The flashlamp includes electrodes preferably made from a tungsten-based alloy for reduced metallic vapor deposition within the flashlamp. Positioned around the outer tube is a packed powder material having a diffuse reflectivity of the order of at least about 98%. The outer surface of the outer tube is placed under an inwardly-directed pressure provided by a pressurized cooling liquid that serves both to cool the flashlamp and simultaneously to offset internally generated pressure within the flashlamp caused by the pressure wave resulting from the movement of the ionization front through the gas within the annular gas chamber defined between the inner and outer tubes.