Ultraviolet spectral efficiencies of surface-spark discharges with emphasis on the iodine photodissociation laser pumpband.

Spectroscopic studies of the uv emission from surface-discharge sparks across Al(2)O(3), BN, ZnO, ZrO(2), BaTiO(3), ZnO-Al(2)O(3), and Cr(2)O(3).Al(2)O(3) substrates have been performed in He, N(2), CO(2), Ar, SF(6), and Ar + i-C(3)F(7)I gases at pressures of 1-10 atm. Considerable differences were found in the performance of the various substrates; based on absolute measurements which are believed to be conservative, an electrical-to-optical conversion efficiency of 9.4 +/- 1.1% for uv emission in the 2500-2900-A iodine-laser pumpband was obtained from discharges across a Cr(2)O(3).Al(2)O(3) substrate in Ar gas. Pumpband energy densities of several J/cm(2) are readily attainable.