Hydrodynamic expansion of a femtosecond laser produced plasma

Visualization of aerosol particles generated by near infrared nano- and femtosecond laser ablation

“…Furthermore, the particles remained strongly confined within a volume of approximately 0.01 cm 3 . Taking into account a moderate mass removal of 1 -10 ng/shot and a mean particle size of 100 nm, this value corresponds to a number density of 2·10 13 -2·10 14 cm -3 which, in turn, yields a particle collision frequency of 10 4 -10 5 Hz if a temperature of 300 K is assumed.…”

Microplasmas: A Review

“…LIF measurements using nanosecond laser in plasmas have been conducted by Nakane et al, [121] and Sdorra and Niemax [122]. In the work of Margetica et al, [123], they use femtosecond LIF to study the expansion of a femtosecond laser produced microplasma at different pressures.…”

“…LIF when compared with emission techniques, has better spatial and temporal resolution and a longer observation time due to the fact that atoms or ions can be excited even after the emission has ceased [123]. A high signal-to-noise ratio exists which allows LIF to have very short observation times during experimental measurements.…”

Images of femtosecond laser plasma plume expansion into background air

“…Although there are several theoretical and experimental studies on the expansion of the plasmas produced by nanosecond lasers [1]- [4], studies for femtosecond lasers are quite limited [5]. We present images for the pressure dependent expansion of the femtosecond laser produced plasma from a copper target.…”

“…This radius represents the point where the energy of the air displaced by the blast wave equals the deposited energy. Previous results with ns [1]- [4] and fs [5] pulses indicate that the expansion occurs up to some fraction of (on the order of 0.3-0.5) where the drag of the background gas brings the expansion to rest. In the present case, the calculated values of are 2.4 and 5.0 mm at 108 and 12 torr, respectively, for the 400 J case assuming 50% absorption.…”