Spectroscopic Diagnostics of Laser Plasma Plume of Aluminum

Abstract

The emission of aluminum Al laser ablated plasma has been investigated in the 200-600 nm spectral range. The most intensive spectral lines were 308.2; 309.3; 394.4 and 396.2 nm Al I. The highest levels of neutral atoms, responsible for the detected spectral lines, correspond to the two-electron excitation with 8.3-9.06 eV energy. The time average value of electron temperature on the 1 and 7 mm distances from the target was calculated. It is 0.43 eV for 1 mm and 0.51 eV for 7 mm distance from the target. The experimentally obtained time of recombination (29 ns) have been used to extract the electron number density at 1 mm from the target which is 9.4×1015 cm-3. The time-resolved emission of atomic spectral lines at 1 mm distance from the target was studied. The maximums of aluminum spectral lines emission have appeared in times of 8-20 ns, which correspond to atom velocities of (0.05-0.13)×10 6 m/s.

State of Research of Low-Energy Aluminum Laser Plasma

“…Radiation of a pulsed infrared laser with a power of 4 × 10 8 W/cm 2 was used and the target of pure aluminum was placed at a distance of 1 mm at a residual gas pressure of 7 Pa. The detailed description of the experimental setup is given in [16].…”