Publications by authors named "Koltashev V"

Efficient room temperature mid-infrared laser action in a Ce-doped chalcogenide fiber was demonstrated. The fiber had a doped selenide glass core in an undoped sulfide glass cladding. The pump source was a CW Fe:ZnSe laser emitting at 4.

View Article and Find Full Text PDF

This Letter reports the experimental realization, for the first time to our knowledge, of lasing in an erbium-doped tellurite fiber at 2.72 µm. The key to the successful implementation was the use of advanced technology for obtaining ultra-dry preforms of tellurite glasses, as well as the creation of single-mode Er-doped tungsten-tellurite fibers with an almost imperceptible absorption band of hydroxyl groups, with a maximum of ∼3 µm.

View Article and Find Full Text PDF

The first, to the best of our knowledge, mid-infrared Q-switched Ce-doped glass laser is demonstrated. As saturable absorbers, Fe:CdSe and Fe:CdTe are used for the first time. When Q-switched by Fe:CdSe, the laser operates in a multi-pulse regime with an individual pulse width of 110 ns, centered at λ = 5.

View Article and Find Full Text PDF

An extensive study of a novel room-temperature mid-infrared Ce-doped GeSbGaSe glass laser is reported. An influence of output-coupler transmission on laser efficiency and emission spectra is investigated. Pumped by a pulsed Fe:ZnSe laser at 4.

View Article and Find Full Text PDF

In high purity -doped selenide glass pumped by a 4.08 µm Fe:ZnSe laser, 5.1-5.

View Article and Find Full Text PDF

The results of the precise measurement of the refractive index of stable germanium isotopes Ge72, Ge73, Ge74, and Ge76 single crystals with high enrichment and a germanium single-crystal Genat of natural isotopic composition with the Fourier-transform interference refractometry method from 1.94 to 20 μm with 0.1  cm resolution and accuracy of 2×10 to 1×10 are shown.

View Article and Find Full Text PDF

The mechanisms of optical losses in bismuth-doped silica glass (Bi:SiO(2)) and fibers were studied. It was found that in the fibers of this composition the up-conversion processes occur even at bismuth concentrations lower than 0.02 at.

View Article and Find Full Text PDF

We performed precise measurement of the refractive index of stable silicon isotopes 28Si, 29Si, and 30Si single crystals with enrichments above 99.9 at.% and a silicon single-crystal natSi of natural isotopic composition with the Fourier-transform interference refractometry method from 1.

View Article and Find Full Text PDF

Raman spectra of germanosilicate core fibers before and after UV irradiation were investigated. Significant changes of the Raman spectra after irradiation indicate transformation of the glass structure. A possible interpretation of the observed changes is proposed.

View Article and Find Full Text PDF

The Raman spectra of phosphosilicate core (P(2)O(5)-SiO(2)) fibers were investigated. Significant changes in the spectra were observed after UV irradiation of the fibers. An interpretation of the photostructural changes confirmed by computer simulation of phosphorus-related centers is proposed.

View Article and Find Full Text PDF

Raman spectra of TeO2-based glasses doped with WO3, ZnO, GeO2, TiO2, MoO3, and Sb2O3 are measured. The intensity of bands in the Raman spectra of MoO3-TeO2 and MoO3-WO3-TeO2 glasses is shown to be 80-95 times higher than that for silica glass. It is shown that these glasses can be considered as one of the most promising materials for Raman fiber amplifiers.

View Article and Find Full Text PDF