Abstract

The purpose of the present work is to show the consequences of a high-power laser-induced plasma on the thermal coupling coefficient. Experimental results obtained by using CO₂ laser sources and metallic targets, put into evidence the influence of the ambient pressure of the surrounding gas as well as its nature. The increase of the thermal coupling coefficient due to the self-radiation is exhibited versus the incident intensity. Indeed the fraction of incident energy absorbed by the plasma is partially re-radiated toward the target on a wide range of wavelength. That leads to a better absorption by the target material especially in the ultraviolet range. Changes in the optical properties of the metal are sometimes evocated to explain this anomalous absorption.¹

© 1995 IEEE