The interpenetration and interaction of supersonic, magnetized tungsten plasma flows has been directly observed via spatially and temporally resolved measurements of the Thomson scattering ion feature. A novel scattering geometry allows independent measurements of the axial and radial velocity components of the ions. The plasma flows are produced via the pulsed power driven ablation of fine tun...

Carbon and tungsten have been radiated by 3ω-YAG laser in the power density range from 2 to 12J/cm/pulse in a laboratory setup with the main objective of investigating the behavior of cluster/aerosol formation from colliding ablation plumes. Direct ion mass spectrometry of colliding carbon plumes has identified Cn-clusters including C, C2,C3,C4 and C5. The formation of these Cn-cluster ions has...

The two-photon absorption (TPA) cross sections (δ) for tungsten(0) arylisocyanides (W(CNAr)6) were determined in the 800-1000 nm region using two-photon luminescence (TPL) spectroscopy. The complexes have high TPA cross sections, in the range 1000-2000 GM at 811.8 nm. In comparison, the cross section at 811.8 nm for tris-(2,2'-bipyridine)ruthenium(ii), [Ru(bpy)3]2+, is 7 GM. All measurements we...

The relaxation of the field ionisation rate after depletion of a tungsten surface is studied for hydrogen and helium with a pulsed laser atom probe. The reduction of the field ion rate and its recovery to a steady state value within some milliseconds is due to a correlation between field ion rate and surface coverage. Three possible models are discussed for explaining the enhancement of the rat...

We report time-resolved studies using femtosecond laser pulses, accompanied by model calculations, that illuminate the difference in the dynamics of ultrashort pulsed laser ablation of different materials. Dielectrics are strongly charged at the surface on the femtosecond time scale and undergo an impulsive Coulomb explosion. This is not seen from metals and semiconductors where the surface cha...

We have investigated field-emission patterns from a clean tungsten tip apex induced by femtosecond laser pulses. Strongly asymmetric modulations of the field-emission intensity distributions are observed depending on the polarization of the light and the laser incidence direction relative to the azimuthal orientation of tip apex. In effect, we have realized an ultrafast pulsed field-emission so...

We present the first spatio-temporal mapping of two simultaneously present species in a plasma used for pulsed laser deposition. We apply laser induced fluorescence spectroscopy (LIF) to map ground state populations of Al and AlO in plasma plumes generated by ablation of LaAlO3 in an O2 or Ar atmosphere. Around a specific distance from the target, we observe Al vanish simultaneously with the tu...

This work investigates evaporation kinetics — the relation between the surface temperature and pressure during excimer laser ablation. Nickel targets are ablated by excimer laser pulses in a laser fluence range between 1 and 6 J/cm2, with the upper limit exceeding the threshold of phase explosion (5 J/cm2). The surface pressure is determined with a polyvinylidene fluoride (PVDF) piezoelectric t...

Third and fifth harmonics of a pulsed infrared laser (1064 nm) delivering pulses of nanosecond duration have been generated in the laser ablation plasmas of various materials including the metals Al and Fe and the highly ionic insulators MgF2 and NaCl. The harmonics were generated in a process triggered by laser ablation followed by frequencyup-conversion of the fundamental laser beam that prop...