Plasma Formation During Dual-Pulse Bichromatic Laser Action on Zirconium in Air

Abstract

The spectra and structure of the near-surface plasma formation and the plume luminosity were experimentally studied with dual-pulse laser action at wavelengths of 1064 and 532 nm on a zirconium target in air as functions of the time interval between laser pulses and their sequence. The dependences of laser plasma temperature on the parameters of the paired laser pulses were established at power densities of q₁₀₆₄ ≈ 3.1∙10⁹ W/cm² and q₅₃₂ ≈ 2.7∙10⁹ W/cm² at laser radiation wavelengths of 1064 and 532 nm, respectively. It was shown that the optimal conditions for excitation of erosion plasma were provided by the action of laser radiation pre-pulses with wavelength of 532 nm and a time interval between laser pulses of 4–5 μs, which was important for increasing the efficiency of laser emission spectral analysis and laser-plasma processing of materials.