Nonlinear absorption of ultra short laser pulses by clusters

Formation of nanoparticles by short and ultra-short laser pulses

The main objective of this study is to explain the experimental observations. To simulate material ablation, plume formation and its evolution, we developed a combined molecular dynamics (MD) and direct simulation Monte Carlo (DSMC) computational study of laser ablation plume evolution. The first process of the material ablation is described by the MD method. The expansion of the ejected plume ...

Laser wakefield acceleration by petawatt ultra-short laser pulses

An ultra-short (about 30 fs) petawatt laser pulse focused with a wide focal spot (about 100 μm) in a rarefied plasma (n0 ∼ 10 cm) excites a nonlinear plasma wakefield which can accelerate injected electrons up to the GeV energy without any pulse channelling. In these conditions, propagation of the laser pulse with an over-critical power for relativistic self-focusing is almost the same as in va...

Droplet deformation and fragmentation by ultra - short laser pulses

We report on the experimental studies of the deformation and fragmentation of liquid metal droplets by picosecond and subpicosecond laser pulses. The experiments were performed with laser irradiance varying in 10-10 W/cm range. The observed evolution of the droplet shape upon the impact dramatically differs from the previously reported for nanosecond laser pulses. Instead of flattening the drop...

Quantum coherent saturable absorption for mid-infrared ultra-short pulses.

We theoretically show that quantum coherent saturable absorption can be used to obtain ultra-short pulses from mid-infrared quantum cascade lasers (QCLs). In this proposal, quantum cascade structures are processed as two electrically isolated sections. The two sections will be biased with two different voltages so that one of the sections produces gain as is done in typical QCLs, while the othe...

Generation of Ultra-short Optical Pulses Using Nonlinear Dynamics