Processing And Characterization Of New Oxy-sulfo-telluride Glasses In The Ge-Sb-Te-S-O System

New oxy-sulfo-telluride glasses have been prepared in the GeSbTeSO system employing a two-step melting process which involves the processing of a chalcogenide glass (ChG) and subsequent melting with TeO2 or Sb2O3. The progressive incorporation of O at the expense of S was found to increase the density and the glass transition temperature and to decrease the molar volume of the investigated oxy-sulfo-telluride glasses. We also observed a shift of the visNIR cut-off wavelength to longer wavelength probably due to changes in Sb coordination within the glass matrix and overall matrix polarizability. Using Raman spectroscopy, correlations have been shown between the formation of Ge- and Sb-based oxysulfide structural units and the S/O ratio. Lastly, two glasses with similar composition (Ge20Sb6S64Te3O7) processed by melting the Ge23Sb7S70 glass with TeO2 or the Ge23Sb2S72Te4 glass with Sb2O3 were found to have slightly different physical, thermal, optical and structural properties. These changes are thought to result mainly from the higher moisture content and sensitivity of the TeO2 starting materials as compared to that of the Sb2O3. © 2010 Elsevier Inc. All rights reserved

Melt Property Variation In GeSe2-As2Se3-PbSe Glass Ceramics For Infrared Gradient Refractive Index (GRIN) Applications

Melt size-dependent physical property variation is examined in a multicomponent GeSe2-As2Se3-PbSe chalcogenide glass developed for gradient refractive index applications. The impact of melting conditions on small (40 g) prototype laboratory-scale melts extended to commercially relevant melt sizes (1.325 kg) have been studied and the role of thermal history variation on physical and optical property evolution in parent glass, the glass\u27 crystallization behavior and post heat-treated glass ceramics, is quantified. As-melted glass morphology, optical homogeneity and heat treatment-induced microstructure following a fixed, two-step nucleation and growth protocol exhibit marked variation with melt size. These attributes are shown to impact crystallization behavior (growth rates, resulting crystalline phase formation) and induced effective refractive index change, neff, in the resulting optical nanocomposite. The magnitude of these changes is discussed based on thermal history related melt conditions

Nonlinear Optical Properties Of GeSbS Chalcogenide Waveguides

We characterize the nonlinear optical properties of GeSbS chalcogenide glasses with fiber-based experiments. A waveguide nonlinear parameter of 7 W-1/m and nonlinear refractive index of 3.71 x 10-18 m2/W are estimated by self-phase modulation. A GeSbS waveguide could also generate a supercontinuum from 1280 to 2120 nm at the -30 dB level for maximum coupled power of 340 W, showing a 14-fold spectral broadening of the input spectrum explained by cascaded stimulated Raman scattering

Thermophysical Properties And Conduction Mechanisms In AsXSe1-X Chalcogenide Glasses Ranging From X = 0.2 To 0.5

The arsenic (As) to selenium (Se) ratio in AsxSe1-x glasses ranging from x = 0.2 to 0.5 was varied in order to examin e the effect of chemical and topological ordering on the glass\u27 thermal transport behavior. The fundamental thermal properties of glass transition temperature (Tg), thermal conductivity (k), and heat capacity (cp) were experimentally measured using differential scanning calorimetry, transient plane source method, and ultrasonic testing. Based on topological constraint theory, inflections in Tg and k were found at the structural coordination number «r» of 2.4, whereas a slight increase in heat capacity (cp) with increasing «r» was observed. A maximum in total thermal conductivity of 0.232 W/m·K was measured for the composition with x = 0.4, which corresponds to the stoichiometric As2Se3. Gas kinetic theory was used to derive an expression for the photon (kp) portion of thermal conductivity, which was calculated by measurements of the glass\u27 absorption coefficient (α) and refractive index (n). Models based on Debye theory were used to derive expressions for specific heat (cv) and the lattice (kl) portion of thermal conductivity. The maximum value for kp was 0.173 W/m·K for the composition with x = 0.2, and a minimum value of 0.144 W/m·K was measured for the composition with x = 0.4. Photonic conduction was found to be the carrier mechanisms in all compositions, comprising 60% to 95% of the measured total thermal conductivity

Influence Of Phase Separation On Structure-Property Relationships In The (Gese2-3As2Se3)1-XPbseX Glass System

The physical properties of chalcogenide glasses in the (GeSe2-3As2Se3)1-xPbSex [GAP-Se] series (x=0-55 mol%) have been measured as a function of PbSe content and glass morphology. Measurements of density, microhardness, thermal properties (glass transition, stability and conductivity) and IR transmission spectra have been correlated with Pb content illustrating the impact of liquid-liquid phase separation (LLPS) on properties within this multicomponent chalcogenide glass system. The role of Pb as both a modifier and network participant is proposed as a structural interpretation of property variation across the series. Density, microhardness and thermal conductivity showed an increase with PbSe content whereas glass transition temperature (Tg) exhibits a minimum near the center of the immiscibility zone correlated to a decrease in glass stability when a Pb-rich matrix is present. The structural origin of the change in the properties is confirmed using Raman spectroscopy and transmission electron microscopy (TEM) which illustrate the different morphology of phase separation present and how it impacts property evolution

Estimation of peak Raman gain coefficients for barium-bismuth-tellurite glasses from spontaneous Raman cross-section experiments

In this paper we explore the TeO2-Bi2O 3-BaO glass family with varied TeO2 concentration for Raman gain applications, and we report, for the first time, the peak Raman gain coefficients of glasses within this glass family extrapolated from non-resonant absolute Raman cross-section measurements at 785 nm. Estimated Raman gain coefficients show peak values of up to 40 times higher than silica for the main TeO2 bands. Other optical properties, including index dispersion from the visible to the long wave Infrared (LWIR) are also summarized in this paper. © 2009 Optical Society of America

Substrate-blind photonic integration based on high-index glass materials

Conventional photonic integration technologies are inevitably substrate-dependent, as different substrate platforms stipulate vastly different device fabrication methods and processing compatibility requirements. Here we capitalize on the unique monolithic integration capacity of composition-engineered non-silicate glass materials (amorphous chalcogenides and transition metal oxides) to enable multifunctional, multi-layer photonic integration on virtually any technically important substrate platforms. We show that high-index glass film deposition and device fabrication can be performed at low temperatures (\u3c 250 °C) without compromising their low loss characteristics, and is thus fully compatible with monolithic integration on a broad range of substrates including semiconductors, plastics, textiles, and metals. Application of the technology is highlighted through three examples: demonstration of high-performance mid-IR photonic sensors on fluoride crystals, direct fabrication of photonic structures on graphene, and 3-D photonic integration on flexible plastic substrates

Impact of Stoichiometry on Structural and Optical Properties of Sputter Deposited Multicomponent Tellurite Glass Films

Multicomponent TeO2-Bi2O3-ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. We observed that thin films sputtered in an oxygen-rich environment are optically transparent while those sputtered in an oxygen-deficient environment exhibit broadband absorption. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy which revealed that the presence of under-coordinated Te leads to the observed optical absorption in oxygen-deficient films

Evidence Of Spatially Selective Refractive Index Modification In 15GeSe2-45As2Se3-40PbSe Glass Ceramic Through Correlation Of Structure And Optical Property Measurements For GRIN Applications

Thermally-induced nucleation and growth of secondary crystalline phases in a parent glass matrix results in the formation of a glass ceramic. Localized, spatial control of the number density and size of the crystal phases formed can yield \u27effective\u27 properties defined approximately by the local volume fraction of each phase present. With spatial control of crystal phase formation, the resulting optical nanocomposite exhibits gradients in physical properties including gradient refractive index (GRIN) profiles. Micro-structural changes quantified via Raman spectroscopy and X-ray diffraction have been correlated to calculated and measured refractive index modification verifying formation of an effective refractive index, neff, with the formation of nanocrystal phases created through thermal heat treatment in a multi-component chalcogenide glass. These findings have been used to define experimental laser irradiation conditions required to induce the conversion from glass to glass ceramic, verified using simulations to model the thermal profiles needed to substantiate the gradient in nanocrystal formation. Pre-nucleated glass underwent spatially varying nanocrystal growth using bandgap laser heating, where the laser beam\u27s thermal profile yielded a gradient in both resulting crystal phase formation and refractive index. The changes in the nanocomposite\u27s micro-Raman signature have been quantified and correlated to crystal phases formed, the material\u27s index change and the resulting GRIN profile. A flat, threedimensional (3D) GRIN nanocomposite focusing element created through use of this approach, is demonstrated

Influence Of Phase Separation On Structure-property Relationships In The (GeSe2-3As2Se3)1-xPbSex Glass System

The physical properties of chalcogenide glasses in the (GeSe2-3As2Se3)1-xPbSex [GAP-Se] series (x=0-55 mol%) have been measured as a function of PbSe content and glass morphology. Measurements of density, microhardness, thermal properties (glass transition, stability and conductivity) and IR transmission spectra have been correlated with Pb content illustrating the impact of liquid-liquid phase separation (LLPS) on properties within this multicomponent chalcogenide glass system. The role of Pb as both a modifier and network participant is proposed as a structural interpretation of property variation across the series. Density, microhardness and thermal conductivity showed an increase with PbSe content whereas glass transition temperature (Tg) exhibits a minimum near the center of the immiscibility zone correlated to a decrease in glass stability when a Pb-rich matrix is present. The structural origin of the change in the properties is confirmed using Raman spectroscopy and transmission electron microscopy (TEM) which illustrate the different morphology of phase separation present and how it impacts property evolution