Field validation of a mobile detection system for laser scattering measurements in the NIR range

Abstract

The accurate quantification of scattered laser radiation is crucial for estimating threats to humans from outdoor applications of high-power lasers. In addition to the hazard due to intrabeam viewing, specular and diffuse reflections from irradiated targets can potentially harm the human eye and skin. Measurement techniques for the detection of scattered laser radiation have been developed in the way to provide quantitative information for advanced analyses as well as proofs and further improvements of laser safety calculations. The detection system has to be calibrated, characterized and validated in order to obtain reliable results. A compact and wavelength-specific detection system is presented, which relies on the technical specifications (i.e. entrance aperture and angular field) according to German laser safety policies. The mobile detection system is deployed at the DLR laser test range in Lampoldshausen (Germany). Field measurements are performed by irradiating metallic targets with high-power laser radiation at 1030 nm and simultaneously measuring the scattered laser radiation with the calibrated detection system. The field of view of the detection system is oriented to the target by using an alignment laser integrated into the detection system. Target samples with different surface roughness are examined in the experiments to analyze specularly and diffusely scattered laser radiation. The dependence of the scattering angle and the distance from the metallic targets to the detection system are investigated. The results are compared to threshold limits of laser safety standards.