Search

We propose a model explaining polarization effects in laser-induced plasma lasers (LIPLs) of the 13th group elements, pumped by a linearly polarized laser beam. The model is based on considering optical transitions between magnetic sublevels involved in the pumping–generation cycle. The model reproduces experimentally observed LIPL polarization features under the np2P1/2, 3/2 → n′s2S1/2 pumping. On the other hand, polarization-resolved collisional-radiative modeling appears to be required for a quantitative explanation of the LIPL polarization when the np2P1/2, 3/2 → n′d2D1/2 pumping is used. [ABSTRACT FROM AUTHOR]

Research was conducted to examine the diffusion of Nd in AgBr crystals which display lasing effects in the near and midinfrared. To determine the diffusion coefficient, the diffusion enthalpy and the temperature dependence of parameters, a technique that involved the monitoring of the infrared luminescence along the direction of diffusion of activator ions in AgBr crystals was used. Results indicate that the low values of the diffusion enthalpy and the high values of the diffusion coefficient hasten the preparation of high optical quality Nd-doped AgBr crystals.

The bulk coefficient of AgBr in AgCl(x)Br(1-x) polycrystalline fibers is 0.00005 per centimeter. The bulk coefficient increases steadily with an increase of molar concentration of chlorine ions to 0.00025 per centimeter. The estimation of the bulk coefficient determines the luminescence properties of the crystals and the effects of absorption and conductivity of the fibers. The absorption of silver halide is caused by cation vacancies, which are bound to dislocations.

LAMIS is a known technique for isotopic shift analysis of light elements, such as B, C, etc. Its application for heavy molecules has been studied less. We proved that vibrational and rotational transitions A(1–0), A(1–2), and A(2–1) of GdO in Laser-Induced Plasma exhibit apparent differences between natural GdO, 156GdO, and 158GdO emissions. The absolute values are in the 0.4–0.5 cm−1 range. Besides its adequate spectral resolution, the Demon HR Double Echelle Monochromator proved its sensitivity for isotopic analysis of Rare Earth Elements. [Display omitted] • We proved isotopic shifts between emissions of 156GdO and 158GdO in LIP. • We proved suitability for the Demon Spectrometer for REE isotopic shift study. • We proposed applications for natural isotopes and radionuclides of Sc and Y. • We proposed LAMIS-MLIF for further development. [ABSTRACT FROM AUTHOR]

Polarization, broadening, and splitting in Fraunhofer-type absorption (FTA) spectra are observed in colinear Double-Pulse Lase-Induced Breakdown Spectroscopy (DP LIBS). Effects are attributable to the Optical Stark Effect (OSE) induced by the electric field of the second laser pulse within the first pulse-created plasma. This effect manifests exclusively in back-directed Laser-Induced Plasma (LIP) emission and during the presence of the second laser pulse. Notably, the OSE is absent in LIBS observations orthogonal to the direction of the laser beams. [Display omitted] • Some Fraunhofer-type absorption lines are polarized in the Double Pulse Laser-induced breakdown spectroscopy in back-directed laser-induced plasma emission geometry. • Polarization in Fraunhofer-type absorption is attributed to the Optical Stark effect induced by the electric field generated by the focused second laser beam. [ABSTRACT FROM AUTHOR]

The absorption coefficients of mixed silver halide crystals and fibers were measured by different laser calorimetric methods: adiabatic for crystals and isothermal for fibers. The composition dependence of the bulk absorption coefficients Beta(sub b) of crystals and polycrystalline fibers at 10.6-micrometer (CO2 radiation) was investigated. It was found that the crystal surface absorption Beta(sub s) is dependent on the surface polishing quality. All experimental results of Beta(sub b) are smaller than those reported in the literature.

The electron-phonon coupling is examined for mid-infrared transitions in silver halide crystals doped with Pr, Dy or Nd and the temperature dependence of the absorption spectral line widths and the line shifts are measured in mid-infrared absorption lines in these crystals. The studies have shown that the temperature dependence is consistent with the two-phonon Raman process model having a single characteristic Debye temperature.