Parameters of 391 nm lasing from molecular nitrogen ions pumped by a 950 nm femtosecond laser pulse.

The results of experimental studies of spectral, temporal, and spatial self-seed lasing characteristics at the wavelength of 391 nm in pure nitrogen at different values of specific pump power are presented. Pumping was carried out by a femtosecond radiation pulse at the wavelength of 950 nm. The possibility of obtaining lasing pulse duration close to transform-limited (1.

Simulation of time-frequency characteristics of a chirped laser beam in a XeF(C-A) amplifier of a THL-100 laser system.

An algorithm for numerical simulation of time-frequency energy distribution of chirped Gaussian laser beams during amplification is proposed. The algorithm is based on a time-frequency description of laser radiation by the Wigner distribution function and the concept of a physical spectrum, which allows one to use the photon transfer equation for modeling the evolution of space, energy, and spectra characteristics of laser radiation. A comparison of the numerical simulation results and experimental measurements of laser radiation characteristics in a XeF(C-A) gas amplifier of a THL-100 hybrid laser system confirmed the applicability of the proposed model.

Speciation of inorganic selenium in natural water by solid-phase extraction using functionalized silica.

Functionalized adsorbents with poly-(4,9-dioxododecane-1,12-guanidine) (SiO-PDDG) and mercaptophenyl groups (MPhS) were used for the separation of Se(VI) and Se(IV) for the first time. Fixation of PDDG was characterized by capillary electrophoresis and TGA/DSC. The quantitative extraction of Se(VI) proceeded due to anion exchange at pH 3-7.

A new method for highly efficient separation and determination of arsenic species in natural water using silica modified with polyamines.

A simple and highly efficient method for the determination of highly toxic arsenic species using non-covalently aminated silica is proposed. The polyamines including poly(hexamethyleneguanidine), poly(4,9-dioxadodecane-1,12-guanidine), hexadimethrine, and poly(diallyldimethylammonium) were tested as silica modifiers. The prepared adsorbents allow effective preconcentration of anionic species of arsenic from aqueous solutions.

Analysis of the active medium parameters of molecular nitrogen ions in ambient air.

In this Letter, we report the direct streak camera measurements of the duration of a lasing pulse from molecular nitrogen ions under various focusing conditions of 10 mJ, 950 nm femtosecond pump pulse in atmospheric pressure air. The parameters of the active medium are analyzed, and a mechanism for formation of picosecond lasing pulse duration at femtosecond seed pulse duration is proposed.