Interferometric System for the Visualization of High-Speed Processes in Laser Plasma

A fundamental to understanding physical processes in laser plasma is to study plasma density profile. We applied an optical interferometer of Mach-Zehnder and UV nitrogen laser that was used as a source of probe light (wavelength 337 nm, energy of ∼ 150 μJ, pulse duration ∼ 5 ns). Digital camera frame grabber captures individual interferometric pictures, so phase shift of fringes is easy photographed and analyzed in terms of plasma density. Powerful Nd-laser (wavelength 1.054 μm, pulse energy up to 20 J, pulse duration ≈15 ns) was used to generate laser plasma. The pulse of probing laser passed through the laser-induced plasma with delay td ≈5÷50 ns. The results of interferometric measurements of electron density in laser-induced plasma from copper target are presented.