Measuring the contribution of atmospheric scatter to laser eye dazzle

An experiment has been conducted to determine the contribution of atmospheric scatter to the severity of the dazzle experienced by a human under illumination from a visible laser. A 15 W 532 nm laser was propagated over a 380 m outdoor range in San Antonio, Texas, over nine data collection sessions spanning June and July 2014. A narrow acceptance angle detector was used to measure scattered laser radiation within the laser beam at different angles from its axis. Atmospheric conditions were logged via a local weather station, and air quality data were taken from a nearby continuous air monitoring station. The measured laser irradiance data showed very little variation across the sessions and a single fitting equation was derived for the atmospheric scatter function. With very conservative estimates of the scatter from the human eye, atmospheric scatter was found to contribute no more than 5% to the overall veiling luminance across the scene for a human observer experiencing laser eye dazzle. It was concluded that atmospheric scatter does not make a significant contribution to laser eye dazzle for short-range laser engagements in atmospheres of good to moderate air quality, which account for 99.5% of conditions in San Antonio, Texas.