Product Code: ILSC2011_902

Predicted Multiple-Pulse Thermal Damage Thresholds and Exposure Limits
Authors:
Clifton Clark, TASC, Inc.; Brooks City-Base USA
Robert Thomas, AFRL 711/HPW RHDO; Brooks City-Base TX
Presented at ILSC 2011

We report on the first of a series of modeling studies examining multiple-pulse damage thresholds in the retina. This effort focuses on near-infrared wavelength (1064nm 1350nm) point source (small spot) thermal damage thresholds, but some general properties of multiple pulse exposures are obtained. We analyze the threshold trends as a function of wavelength, pulse width, inter-pulse spacing, and number of pulses, spanning a large parameter space.
The rules used for determining multiple-pulse maximum permissible exposures (MPEs) in the current ANSI Z136.1 standard are evaluated, and we show that the MPE trends to not follow the damage threshold trends for many pulse train configurations, leading to large variations in the safety factor. We investigate a system for setting multiple-pulse MPEs that more closely follows the damage threshold trends, and also propose changes to the current multiple-pulse MPE rules.