Shock-wave velocity of a femtosecond-laser-produced plasma

článek v časopise - ostatní, Jost

angličtina

Fluorescence measurements have been used to characterize the velocity of atoms in a femtosecond-laser-produced plasma. Nanogram amounts of a copper sample were ablated by the focused radiation (lambda = 775 nm) of an all-solid-state laser. The laser was operated at a pulse rate of 10 Hz with an energy of 200 muJ per pulse. The microplasma expanded into a defined argon atmosphere of pressures between 0.02 and 850 mbar. Atomic fluorescence was excited in the laser plume by a dye-laser pulse with the wavelength set to the line Cu I 282.4 nm. The narrowed beam of the dye-laser was directed into the plasma at different heights above the sample surface. The fluorescence radiation was raeasured with an echelle-spectrometer, equipped with an intensified-charge-coupled device as the detector. The velocity depends strongly on the pressure of the ambient atmosphere and the distance from the sample surface. The highest velocity found at an argon pressure of 0.02 mbar was 1.0 X 10(6) cm s(-1).

atomic fluorescence; femtosecond laser; laser-induced plasma

Margetic V, Ban T, Samek O, Leis F, Niemax K, Hergenroder R

2004

1. 4. 2004

0011-4626

Czechoslovak Journal of Physics

54

4

Česká republika

423

428

6