Optical spectroscopy of plasma produced by laser ablation of Ti alloy in air

Time-resolved emission spectrum from the plasma produced by 1.06 μm, 10 ns pulsed-laser irradiation of titanium alloy targets in air at a flux of 9.3×109 W cm−2 was analyzed in the wavelength range of 2000–8800 Å. From the evolutions of the specific spectrum lines of N II, Ti I, and Fe I, the velocities of N+ ions and the excited neutral Ti and Fe atoms have been obtained using a time-of-flight diagnostic method. The electron temperatures were deduced using the relative emission intensities of N II and Fe I isolated spectrum lines, and an electron number density was determined from the Stark-broadened line of the N II line at wavelength λ=3995 Å.