A new technique of the excited-state photoionization studies in Ce:LiYF 4 and Ce:LiLuF 4 crystals

The new method of photodynamic processes investigations in UV active media based on the analysis of the activator ions fluorescence decay is proposed. The excited-state photoionization spectra from 5d-state of Ce 3+ ions in LiYF 4 and LiLuF 4 are determined. Photoelectrons and holes recombination and trapping cross-sections are estimated. The terminal state of excited-state photoionization is attributed to the 6s configuration of Ce 3+, located in the conduction band of the host material. © 2011 Elsevier B.V

New all-solid-state tunable UV Ce3+, Yb3+:LiY0.4Lu0.6F4 laser

Here we report laser test results of the new UV solid-state active medium based on a Ce3+, Yb3+:LiY0.4Lu0.6F4 mixed crystal pumped by radiation from Ce:LiCAF laser. The 10-Hz pulse repetition rate Ce3+, Yb3+:LiY0.4Lu0.6F4 laser yielded a maximum output power of 0.25 mJ at 311nm in non-optimized non-selective resonator with a maximal slope efficiency of 13%. Tunability from 304 to 332 nm was achieved in the selective single-prism resonator. © 2012 Pleiades Publishing, Ltd

Site-selective spectroscopy of Ce3+ and Yb3+ ions in double-doped SrAlF5 crystals

This paper reports a study of absorption, luminescence and excitation spectra of single- and double-doped Ce3+,Yb3+:SrAlF 5 (0.5 at%.) single crystals. Spectral properties of different types of impurity centers of Ce3+, Yb3+ and Yb2+ ions are described. Experimental energy level diagrams for optically nonequivalent Ce3+, Yb2+ and Yb3+ centers in double-doped Ce3+, Yb3+: SrAlF5 single crystals are suggested. Lasing on Ce:SAF single crystal at 290 nm under 248 nm pumping was demonstrated for the first time. © 2013 Published by Elsevier B.V

Photodynamic processes and laser performance of Ce, Yb: LiYXLu1-XF4 mixed crystals

Photodynamic processes and temperature dependencies of lasing in Ce+Yb:LYLF mixed crystals are investigated. The mechanisms leading to the observed phenomena and allowing control on the optical qualities of the active media are discussed. © OSA 2013

Spectral-kinetic studies of SrAlF 5 doped by trivalent rare-earth ions

Photochemical properties of Ce 3:SrAlF 5 and Ce 3,Yb 3:SrAlF 5 single crystals together with spectroscopic and kinetic characteristics of several optically nonequivalent impurity centers and energy transfer between them are described. It is shown that co-activation by Yb 3 ions effectively suppresses color centers in Ce,Yb:SAF crystals. It was found out that in Ce,Yb:SAF crystals Yb ions exist simultaneously in 2 and 3 valent state. Three types of optically nonequivalent luminescent centers corresponding to the doublets in luminescence spectrum centered at 290, 305 and 370 nm (Ce I, Ce II, Ce III, respectively) have been observed. Analysis of luminescence spectra and decays leads to the conclusion that there is no energy transfer between either cerium centers or from Ce 3 to Yb 2 apart from the Ce III center which luminescence is slightly quenched by Yb 2. © 2012 Elsevier B.V. All rights reserved

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Investigation of the photoionization of Ce3+ ions in a YAG crystal by microwave resonance technique

The kinetic and spectral characteristics of the complex dielectric constant of a Ce: YAG crystal under laser irradiation in 250-275 nm spectral range are investigated. The lifetimes of free charge carriers and charge carriers, localized at the lattice defects (color centers), are estimated. It was established that photoconductivity signal of the sample is essentially caused by one-photon ionization processes from the 2F5/2 ground state of Ce3+ ions. © 2013 Pleiades Publishing, Ltd

Anterior urethral strictures - actual questions of treatment

The article presents data on modern methods of reconstructive surgery of the anterior urethra stricture. Compared the effectiveness of various methods of graft augmentation urethroplasty techniques (ventral, dorsal, lateral bulbar augmentation urethroplasty, Asopa and Palminteri techniques). Authors give recommendation of technical advantages of using a particular surgery method. Provides information on the graft selection and some features of its fixation. Highlight aspects of the treatment of urethra stricture in the future.В статье представлены данные о современных реконструктивно-пластических методиках хирургического лечения стриктур передней уретры. Представлен анализ данных 66 статей, посвященных сравнению эффективности различных методик заместительной пластики уретры (вентральная, дорсальная, латеральная методика, техники Asopa и Palminteri и др.) и их отдаленных результатов. Даются рекомендации по технике и преимуществам использования той или иной методики. Приведена информация по вопросам выбора трансплантата и так же особенностям его забора и фиксации. Освещены аспекты развития методов лечения стриктурной болезни уретры в будущем

Site-selective spectroscopy of Ce3+ and Yb3+ ions in double-doped SrAlF5 crystals

This paper reports a study of absorption, luminescence and excitation spectra of single- and double-doped Ce3+,Yb3+:SrAlF 5 (0.5 at%.) single crystals. Spectral properties of different types of impurity centers of Ce3+, Yb3+ and Yb2+ ions are described. Experimental energy level diagrams for optically nonequivalent Ce3+, Yb2+ and Yb3+ centers in double-doped Ce3+, Yb3+: SrAlF5 single crystals are suggested. Lasing on Ce:SAF single crystal at 290 nm under 248 nm pumping was demonstrated for the first time. © 2013 Published by Elsevier B.V