Laser damage tests and optical densities of laser goggles

We describe the experimental set-up used to determine the optical densities and the laser damage threshold of laser goggles. Optical densities have been measured at 1064 nm using 3ns laser pulses on an upgraded automatic test bench, which also allows for the determination of laser damage threshold of otpical components. We have performed experiments at constant fluence by varying different parameters such as the angle of incidence, the light polarization, the laser repetition rate, and the spot size. Multiple shot data are obtained in real time, which enables us to detect optical density variations during the laser exposure. From our study, we can conclude that a few goggles show the well known effect of saturable absorbers. This means that, above a given thresholds energy, the goggles become transparent. Finally, we will present a simple model which allows to understand the behavior of the laser damage threshold of polycarbonate goggles under these various conditions.