UV Laser Decay of Oxygen-Deficient Centers in Silica Glasses

Oxygen-deficient centers decay with simultaneous formation of color centers in IR and UV grade silica glasses under KrF laser irradiation was studied. The nonexponential dependence of the ODC photodecay in silica glass on the UV irradiation dose (number of laser pulses) was observed. Postpulse long-time temporal behaviour of recombination luminescence and laser induced photoconductivity was analyzed for the two types of glasses in time scale up to 0.5 ms. Long time fluorescence tail is attributed to migration of electrons through the shallow traps before recombination and recovery of ODC. The models of postpulse recombination which can explain the observed nonexponential behaviour of ODC decay (geminal and homogeneous) are discussed. The principle part of impurities caused electron traps in the postpulse ODC recombination is shown.