Measurement of the three-photon absorption cross section in KI at 532 nm utilizing exciton recombination luminescence

The intrinsic recombination luminescence of the self-trapped exciton was utilized in the measurement of the three-photon absorption cross section in KI at 532 nm. Proper interpretation of the experimental observations required careful analysis of the kinetics describing the excitation and relaxation processes. The experimental results were incorporated in a theoretical study of the role of laser-induced primary defect formation in optical breakdown of KI exposed to short laser pulses at 532 nm. The net effect of the photochemical processes was found to be a slight reduction in the damage threshold and a marked decrease of the three carrier densities required for damage to occur