Search results for "CHALCOGENIDE"

Nonlinear Characterisation of an AsSe Chalcogenide Holey Fiber

2009

oral session TuA " Highly Nonlinear Fibers " [TuA1]; International audience; We report the nonlinear characterization of a chalcogenide holey fiber, based on the AsSe glass composition. A nonlinear coefficient as high as 15 000 W-1 km-1 has been measured.

Chalcogenide thin films for direct resistors fabrication and trimming

2004

Abstract The fabrication of thin film resistors based on Ge–Sb–Te chalcogenide alloys is proposed. By exploiting the phase change properties of the deposited film, a laser beam is used for inducing a transition from high to low resistivity along selected paths. Conductivity changes as high as four orders of magnitude can be routinely achieved. This candidates the technique for maskless fabrication of compact precision resistors for a variety of applications.

Génération de supercontinuum infrarouge et enjeux de vieillissement au sein de fibres optiques à coeur suspendu hautement non linéaires en verre de c…

2014

The work reported in this thesis deals with the fabrication of suspended core chalcogenide microstructured optical fibers (MOFs) for supercontinuum generation (SCG) beyond 6 μm. In this context, As2S3-based suspended-core MOFs were fabricated under vacuum, and loss threshold of 1-2 dB/m at 2.9µm were systematically registered. In addition, MOFs were designed with core diameter ranging from 1.5 to 3.5µm, allowing therefore to control the MOF's dispersive properties and to shift corresponding zero dispersion wavelength to 2.0-2.5 µm range. SCG experiments were performed by pumping the fabricated MOFs in their anomalous dispersion regime by means of tunable femtosecond laser source. Simultaneo…

Simulation of mid-IR amplification in Er3+-doped chalcogenide microstructured optical fiber

2009

International audience; This paper deals with the design of an erbium doped microstructured optical fiber (MOF) amplifier operating in the mid-infrared (mid-IR) wavelength range, more precisely around 4.5 µm wavelength. A homemade numerical code which solves the rate equations and the power propagation equations has been ad hoc developed to theoretically investigate the feasibility of mid-IR MOF amplifier. On the basis of the measured energy level transition parameters of a Er3+-doped Ga5Ge20Sb10S65 chalcogenide glass, the amplifier feasibility is demonstrated exhibiting high gain and low noise figure.

Kinetics of phase transitions in vitreous chalcogenide semiconductors AsxSe100m-x-yBiyas studied by the differential thermal analysis and exoelectron…

2011

Kinetics of glass transition (retrification) in chalcogenide semiconductors AsxSe100-x-yBy (x = 20 or 30, and y = 0 and 1) has been investigated by parallel differential thermal analysis (DTA) and exoelectron emission (EEE) measurements. EEE is a surface effect accompanying the structural transformations in the surface layer, whereas the DTA technique gives information about the transformations occurring in the volume of the sample. Temperature dependencies of the DTA signal and of the EEE intensity have been determined and the values of the activation energy for both the volume and the surface retrification have been determined by the Ozawa method for each of the four investigated material…

Syntheses, Structures, and Properties of New Quaternary Gold-Chalcogenides: K2Au2Ge2S6, K2Au2Sn2Se6, and Cs2Au2SnS4

1998

The new compounds K2Au2Ge2S6 (1), K2Au2Sn2Se6 (2), and Cs2Au2SnS4 (3) have been synthesized through direct reaction of the elements with a molten polyalkalithiogermanate(stannate) flux at 650, 550, and 400 °C, respectively. Their crystal structures have been determined by single crystal X-ray diffraction techniques. 1 crystallizes in the monoclinic space group P21/n with a = 10.633(2) A, b = 11.127(2) A, c = 11.303(2) A, β = 115,37(3)°, V = 1208,2(3) A3 and Z = 4, final R(Rw) = 0.045(0.106). 2 crystallizes in the tetragonal space group P4/mcc with a = 8.251(1) A, c = 19.961(4) A, V = 1358,9(4) A3 and Z = 4, final R(Rw) = 0.040(0.076). 3 crystallizes in the orthorhombic space group Fddd with…

Synthetic Approaches to Functionalized Chalcogenide Nanotubes

2008

Cavity Control of Excitons in Two-Dimensional Materials

2018

We propose a robust and efficient way of controlling the optical spectra of two-dimensional materials and van der Waals heterostructures by quantum cavity embedding. The cavity light-matter coupling leads to the formation of exciton-polaritons, a superposition of photons and excitons. Our first principles study demonstrates a reordering and mixing of bright and dark excitons spectral features and in the case of a type II van-der-Waals heterostructure an inversion of intra and interlayer excitonic resonances. We further show that the cavity light-matter coupling strongly depends on the dielectric environment and can be controlled by encapsulating the active 2D crystal in another dielectric m…

Positronics of radiation-induced effects in chalcogenide glassy semiconductors

2015

Using As2S3 and AsS2 glasses as an example, the principal possibility of using positron annihilation spectroscopy methods for studying the evolution of the free volume of hollow nanoobjects in chalcogenide glassy semiconductors exposed to radiation is shown. The results obtained by measurements of the positron annihilation lifetime and Doppler broadening of the annihilation line in reverse chronological order are in full agreement with the optical spectroscopy data in the region of the fundamental absorption edge, being adequately described within coordination defect-formation and physical-aging models.

Out-of-plane transport of 1T-TaS2/graphene-based van der Waals heterostructures

2021

Due to their anisotropy, layered materials are excellent candidates for studying the interplay between the in-plane and out-of-plane entanglement in strongly correlated systems. A relevant example is provided by 1T-TaS2, which exhibits a multifaceted electronic and magnetic scenario due to the existence of several charge density wave (CDW) configurations. It includes quantum hidden phases, superconductivity and exotic quantum spin liquid (QSL) states, which are highly dependent on the out-of-plane stacking of the CDW. In this system, the interlayer stacking of the CDW is crucial for the interpretation of the underlying electronic and magnetic phase diagram. Here, thin-layers of 1T-TaS2 are …