We consider the linear density response of a two-component ~superfluid! Fermi gas of atoms when the perturbation is caused by laser light. We show that various types of laser excitation scheme can be transformed into linear density perturbations; however, a Bragg spectroscopy scheme is needed for transferring energy and momentum into a collective mode. This makes other types of laser probing sc...

2014 A one-dimensional model oriented toward a thorough understanding of line and continuum emission from a CO2 laser-induced helium plasma is presented. The model combines a time-dependent calculation of the ionization and radiation dynamics with a lagrangian hydrodynamic simulation code. Detailed collisional radiative models involving many neutral and ion excited levels are used to predict th...

The concepts of matched-beam, self-guided laser propagation and ionization-induced injection have been combined to accelerate electrons up to 1.45 GeV energy in a laser wakefield accelerator. From the spatial and spectral content of the laser light exiting the plasma, we infer that the 60 fs, 110 TW laser pulse is guided and excites a wake over the entire 1.3 cm length of the gas cell at densit...

XeF( C --* A ) laser radiation has been produced in a fivecomponent gas mixture excited by a coaxial electron beam with an intermediate pulse length ( 175 ns) and pumping rate ( 1 MW/cm'). The laser output energy was 215 mJ from an active volume of 157 cm3 (1.4 J / L ) at a total gas pressure of 8 bar corresponding to an intrinsic

The study of blast waves produced by intense lasers in gases is motivated by the desire to explore astrophysically relevant hydrodynamic phenomena in the laboratory. A systematic scan of laser produced blast waves was performed and the structure of blast waves was examined over a wide range of drive laser energy. Lasers with energies ranging from 10–1000 J illuminated a pin target in either xen...

When background gas is present in pulsed laser– material interaction, a shock wave down to the nanoscale will emerge. The background gas will affect the phase change and explosion in the target. This study is focused on the void dynamics and stress wave in a model material (argon crystal) under picosecond pulsed laser irradiation. Our results show that existence of ambient gas and the shock wav...

Plasma expansion with shockwave formation during laser ablation of materials in a background gasses is a complex process. The spatial and temporal evolution of pressure, temperature, density, and velocity fields is needed for its complete understanding. We have studied the expansion of femtosecond (fs) laser-ablated aluminum (Al) plumes in Argon (Ar) gas at 0.5 and 1 atmosphere (atm). The expan...

Laser desorption mass spectrometry was used in the production and analysis of gas phase metal sulfur clusters. Clusters of gas phase aluminum, gallium, and indium sulfur were produced and analyzed using a time-of-flight mass spectrometer. Also, carbon nano-onions produced by an arc between graphite electrodes in water and the annealing of nanodiamonds were analyzed. The sulfur experiments were ...

We demonstrate for the first time an optically pumped gas laser based on population inversion using a hollow core photonic crystal fiber (HC-PCF). The HC-PCF filled with 12C2H2 gas is pumped with ~5 ns pulses at 1.52 μm and lases at 3.12 μm and 3.16 μm in the mid-infrared spectral region. The maximum measured laser pulse energy of ~6 nJ was obtained at a gas pressure of 7 torr with a fiber with...