Experimental Studies of Reflection Ability of Liquid Metal Targets in Vacuum Under Conditions of Neodymium Laser Pulse Radiation

Abstract

Melting and evaporation stages of metals are in the basis of numerous technological processes developed in the field of metal treatment. Lasers enable to heat the surface of metals by powerful short-term radiation that considerably changes the properties of their surface. The necessity to study the optical characteristics of metals and alloys subjected to such treatment becomes of vital importance.

This paper considers the method and represents the measurement results of solid and liquid metal target reflection ability in vacuum under neodymium laser impulse effect acting in the mode of free generation. The techniques presented are based on the comparative method of reflection factor RF measurement and a widely-spread method of measuring a reflection factor of diffusionally scattering surface described by Taylor . The measurements were taken during a hundred ms after the laser impulse effect on the target using a system of laser synchronization with spectral RF measurement. The RF temperature dependence for fermenting metals (tin, indium) within the interval of 20’C to 350’C has been obtained for optical ranges of scanning emission in vacuum no more 10⁻⁴ Ton under the neodymium laser effect (facility GOS-1001), the beam energy up to 1 kJ and maximum emission power density at the target being 10⁵ W/cm².