Femtosecond Double-Pulse Laser Ablation and Deposition of Co-Doped ZnS Thin Films.

Nanostructured thin films of Co-doped zinc sulfide were synthesized through femtosecond pulsed laser deposition. The scheme involved ablation of physically mixed Co and ZnS with pairs of ultrashort pulses separated in time in the 0-300 ps range. In situ monitorization of the deposition process was carried out through a simultaneous reflectivity measurement.

Femtochemistry under scrutiny: Clocking state-resolved channels in the photodissociation of CHI in the A-band.

Clocking of electronically and vibrationally state-resolved channels of the fast photodissociation of CHI in the A-band is re-examined in a combined experimental and theoretical study. Experimentally, a femtosecond pump-probe scheme is employed in the modality of resonant probing by resonance enhanced multiphoton ionization (REMPI) of the methyl fragment in different vibrational states and detection through fragment velocity map ion (VMI) imaging as a function of the time delay. We revisit excitation to the center of the A-band at 268 nm and report new results for excitation to the blue of the band center at 243 nm.

Coulomb Explosion Imaging for the Visualization of a Conical Intersection.

Coulomb explosion imaging is proposed as a method to directly map the presence of conical intersections encountered by a propagating wave packet in a molecular system. The case of choice is the nonadiabatic coupling between two dissociative surfaces in the methyl iodide molecule, probed by Coulomb explosion with short, intense near-infrared pulses causing multiple ionization. On-the-fly multidimensional trajectory calculations with surface hopping using perturbation theory and including spin-orbit coupling are performed to visualize the dynamics through the conical intersection and compare with experimental results.

Observation of middle-sized metal clusters in femtosecond laser ablation plasmas through nonlinear optics.

Femtosecond laser ablation of solids is known to produce ejection of material to a large extent composed of particles of nanometer dimensions for a broad variety of targets. This work explores the ultrashort laser ablation of metal targets (Ag, Cu, Al, Mn) through non-conventional diagnostics based on the nonlinear response of the transient medium created upon ablation. The full temporal mapping of the nonlinear response constitutes a useful flag that signals the abundance of clusters and nanoparticles in the plume.

Strong laser field control of fragment spatial distributions from a photodissociation reaction.

The notion that strong laser light can intervene and modify the dynamical processes of matter has been demonstrated and exploited both in gas and condensed phases. The central objective of laser control schemes has been the modification of branching ratios in chemical processes, under the philosophy that conveniently tailored light can steer the dynamics of a chemical mechanism towards desired targets. Less explored is the role that strong laser control can play on chemical stereodynamics, i.