[en] Single-crystalline Tm3+-doped calcium fluoride (Tm3+:CaF2) films were grown onto (100) oriented undoped bulk CaF2 substrates by Liquid Phase Epitaxy method using LiF as a solvent. The growth was performed at the temperatures of 853–865 °C. Crack-free transparent films with a high doping concentration of ∼6 at.% and a thickness up to ∼100 μm were obtained. The film structure and morphology were characterized by confocal microscopy, X-ray diffraction and scanning electron microscopy. High resolution X-ray diffraction and reciprocal space mapping confirmed the high crystallinity and the low mosaicity of the films. Energy-Dispersive X-ray spectroscopy revealed a uniform distribution of Tm3+ ions in the films. The Tm3+:CaF2 films exhibit a broadband emission at ∼2 μm and are of interest for waveguide lasers. The use of CaF2–LiF binary system is also promising for fabrication of other rare-earth-doped CaF2 layers.
Journal
[en] Experimental measurements of the time variation of gas temperature in a non-equilibrium hydrogen-methane microwave plasma operating at medium pressure and under pulsed mode are presented. The hydrogen plasma is created using a 915 MHz microwave generator at an input microwave power up to 17 kW and the gas temperature is determined from the rotational distribution of the G 1Σg+ excited state of H2(T(G)). In continuous discharge, the rotational temperature T(G) of H2(G 1Σg+) is found to be nearly equal to the gas temperature determined from rotational distribution of the a3Πu metastable state of C2 molecule obtained from absorption spectroscopy. The time evolution of H2(G 1Σg+) rotational distribution in pulsed discharges reaches a Boltzmann equilibrium only 100 μs after the beginning of the pulse. Variations of the T(G) in-pulse value as a function of pressure, volumetric power density and gas velocity is studied. (author)
Journal
Journal of Physics. D, Applied Physics; ISSN 0022-3727; 
; v. 35(16); p. 1939-1945
; v. 35(16); p. 1939-1945
[en] This article attempts to give an overview of atmospheric plasma sources and their applications. The aim is to introduce, in a first part, the main scientific background concerning plasmas as well as the different atmospheric plasma sources (description, working principle). The second part focuses on the various applications of the atmospheric plasma technologies, mainly in the field of surface treatments. Thus this paper is meant for a broad audience: non-plasma-specialized readers will find basic information for an introduction to plasmas whereas plasma spectroscopists who are familiar with analytical plasmas may be interested in the synthesis of the different applications of the atmospheric pressure plasma sources
Journal