Upconverting particles in near-infrared light-induced TiO photocatalysis: towards the optimal architecture of upconverter/photocatalyst systems.

Preparation of highly active core-shell/hybrid materials based on up-converting particles combined with semiconductors for photocatalytic application usually requires sophisticated and multi-step synthesis procedures. We propose a new design of a highly efficient NIR-driven photocatalytic system composed of spatially separated thin films of upconverting NaYF:Yb,Tm particles (UCPs), and TiO. Several samples of UCPs were prepared in the form of thin films and suspensions, directly coated with a titania layer or mixed with P25.

Reexamining the Stark width and shift of He ii Paschen-α: Studies using laser-induced plasma, Thomson scattering, and computer simulations.

We report on experimental and theoretical studies on the Stark profile of the He ii Paschen-α line over a wide range of plasma parameters. This line was emitted from a laser-induced plasma with electron densities in the range of 8.1×10^{22}-4.

Plasma Stark effect of He ii Paschen-α: Resolution of the disagreement between experiment and theory.

There is a significant disagreement between the experimental and theoretical plasma Stark shift of the hydrogenlike helium Paschen-α line (λ=468.568nm). Here, it is demonstrated that the controversy can be resolved by accounting for the plasma polarization shift and other related effects arising from the charged plasma particles penetrating the wave-function extent of the bound electron.

Studies of spectral line merging in a laser-induced hydrogen plasma diagnosed with two-color Thomson scattering.

Laser-induced hydrogen plasma in the density and temperature range of (0.1-5)×10^{23}m^{-3} and (6000-20000)K, respectively, was precisely diagnosed using two-color Thomson scattering technique, inferring the electron number density, electron temperature as well as ion temperature. Simultaneously, spectra of the Balmer series of spectral lines from H-β to H-ζ were measured and plasma emission coefficient calculated within the quasicontiguous frequency-fluctuation model.

Experimental investigations of plasma perturbation in Thomson scattering applied to thermal plasma diagnostics.

Time and space resolved measurements of Thomson scattering of 532 nm , 6 ns laser pulses were performed on argon thermal discharge plasma with electron temperature T(e)>10,000 K and electron density 8 x 10(22) m(-3)< n(e)<2 x 10(23) m(-3). From these measurements, variations of the electron density and temperature across the laser beam and their evolution during the laser pulse were determined. While the electron density is augmented by no more than a few percent the electron temperature is significantly increased along the axis of the laser beam due to laser heating.

Calculations of Stark-broadened line shapes in phase-conjugate degenerate four-wave mixing laser spectroscopy.

The Stark-broadened line shapes for phase-conjugate degenerate four-wave mixing (PCDFWM) laser spectroscopy are studied. The line profiles are calculated for high-density (N(e) > 10(21) m(-3) plasma conditions and for different contributions of the Doppler broadening. Calculations are performed in the limit of low laser intensities using the perturbation approach.