V O Nazaryants

Refractive index spectral dependence, Raman spectra, and transmission spectra of high-purity Si28, Si29, Si30, and Sinat single crystals

Precise measurement of the refractive index of stable silicon isotopes Si, Si, Si single crystals with enrichments above 99.9 at.% and a silicon single crystal Si of natural isotopic composition is performed with the Fourier-transform interference refractometry method from 1.06 to more than 80 μm with 0.1 cm resolution and accuracy of 2 × 10 . . . 1 × 10. The oxygen and carbon concentrations in all crystals are within 5 × 10 cm and the content of metal impurities is 10 . . . 10 at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.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 1.06 to more than 80 μm with 0.1 cm(-1) resolution and accuracy of 2×10(-5)…1×10(-4). The oxygen and carbon concentrations in all crystals are within 5×10(15) cm(-3), and the content of the metal impurities is 10(-5)…10(-6) at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of the generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.

Spectral dependence of the refractive index of single-crystalline GaAs for optical applications

The refractive index of crystalline GaAs is measured by the method of interference refractometry in the wavenumber range from 10?500 to 540?cm?1 (or the wavelength range from 0.9 to 18.6??m) with a resolution of 0.1?cm?1. The measurement results are approximated by the generalized Cauchy dispersion formula of the 8th power. Spectral wavelength dependences of the first- and second-order derivatives of the refractive index are calculated, and the zero material dispersion wavelength is found to be ?0 = 6.61??m. Using three GaAs plates of different thicknesses we managed to raise the refractive index measurement accuracy up to 4 ? 10?4 or 0.02%, being nearly by an order of magnitude better than the data available.

Spectral dependence of the refractive index of chemical vapor deposition ZnSe grown on substrate with an optimized temperature increase

Precise measurement of the refractive index of chemical vapor deposition (CVD) ZnSe with the Fourier-transform interference refractometry method from 0.9 to 21.7microm (from 11,000 to 460cm(-1)) with 0.1cm(-1) resolution is described. For this measurement, structurally homogeneous ZnSe plates were grown on a substrate with an optimized temperature increase. Using three ZnSe plates of different thicknesses, we managed to raise the measurement accuracy of the refractive index up to 2x10(-5) (being nearly 1 order of magnitude better than the available data) in the near IR and most of the middle IR wavelength range from 0.9 to 12.5microm (wavenumber range of 11,000-800cm(-1)) and up to 1...4x10(-4) in the 12.5-21.7microm (800-460cm(-1)) region. The experimental results are approximated by a generalized Cauchy dispersion function of the 8th power. Spectral wavelength dependencies of the first- and second-order derivatives of the refractive index are calculated, and the zero material dispersion wavelength is found to be lambda(0)=4.84microm.

Computer modelling of tungsten-tellurite photonic crystal optical fibres for parametric fibre devices

Computer modelling of light propagation in optical fibres formed by vacancies in two-dimensional periodic lattices is performed using the MIT Photonic-Bands package to calculate fully vectorial definite-frequency eigenmodes of Maxwells equations with periodic boundary conditions in a plane-wave basis. The lattices consist of cylindrical holes in bulk glass or of glass tubes with the holes and gaps between the tubes filled with air. Single-site hexagonal and square lattices, often studied both theoretically and experimentally and used in manufacturing silica glass-based photonic crystal optical fibres, are considered. The calculations are carried out for the 80TeO2–20WO3 tungsten–tellurite glass-based fibres with the refractive index frequency dispersion taken into account. The numerical solutions are analysed by the effective mode area approach. The modelled dependences of fundamental mode dispersion on geometrical parameters of the fibres are used to suggest tungsten–tellurite photonic crystal fibres of several types for parametric devices.

Dispersion and guidance characteristics of microstructured 68TeO{sub 2} - 22WO{sub 3} - 8La{sub 2}O{sub 3} - 2Bi{sub 2}O{sub 3} glass fibres for supercontinuum generation

We report the preparation of a high-purity optical-quality four-component glass of composition 68TeO2 — 22WO3 — 8La2O3 — 2Bi2O3, containing (2.7±0.5)×10-5 mol % OH groups. Its refractive index has been determined in the range 0.9 — 5.45 μm using interference refractometry. The data are used to assess the dispersion and guidance characteristics of microstructured optical fibres potentially attractive for supercontinuum generation in the range 1 — 5 μm

Near- to mid-IR refractive index of {sup 28}Si, {sup 29}Si and {sup 30}Si monoisotopic single crystals

We have prepared 28Si, 29Si and 30Si single crystals with enrichments above 99.9 at % and a silicon single crystal of natural isotopic composition. The oxygen and carbon concentrations in all the crystals are within 5×1015 cm-3, and the content of metal impurities is 0.01 — 0.1 ppma. The refractive index of the crystals has been determined in the range 1.05–25.5 μm using interference refractometry, and its dispersion and material dispersion have been determined.

Numerical simulation of photonic-crystal tellurite-tungstate glass fibres used in parametric fibre devices

Using the MIT Photonic-Bands Package to calculate fully vectorial definite-mode eigenmodes of Maxwells equations with periodic boundary conditions in a plane-wave basis, light propagation is simulated in fibres formed by point defects in two-dimensional periodic lattices of cylindrical holes in a glass or of glass tubes. The holes and gaps between tubes are assumed filled with air. Single-site hexagonal and square lattices are considered, which were most often studied both theoretically and experimentally and are used to fabricate silica photonic-crystal fibres. As a defect, a single vacancy is studied — the absent lattice site (one hole in a glass or one of the tubes are filled with the same glass) and a similar vacancy with nearest neighbours representing holes of a larger diameter. The obtained solutions are analysed by the method of effective mode area. The dependences of the effective refractive index and dispersion of the fundamental mode on the geometrical parameters of a fibre are found. The calculations are performed for tellurite-tungstate 80TeO2–20WO3 glass fibres taking into account the frequency dispersion of the refractive index.