Bottleneck optical pulse limiters revisited

Analytic expressions are presented for the fluence dependence of the populations of pulse-excited singlet and triplet states of metallo-organic molecules appropriate for the design of passive optical limiters in which the molecular density profile along the axis of a convergent beam is graded to avoid damage at high design fluences. The original model was relevant strictly for laser-pulse lengths greater than 10(-7) s. This research extends the model to the range from 10(-11) to 10(-6) s and beyond. The factors that determine the appropriate concentration profiles, and the high-fluence performance of the device, are also reviewed.