Ultrabroadband mid-infrared emission from Cr~(2+):ZnSe-doped chalcogenide glasses prepared via hot uniaxial pressing and melt-quenching

We reported an ultrabroadband mid-infrared(MIR) emission in the range of 1800 nm–3100 nm at room temperature(RT) from a Cr~(2+):Zn Se-doped chalcogenide glasses(Ch Gs) and studied the emission-dependent properties on the doping methods. A series of Cr~(2+):Zn Se/As40 S57 Se3(in unit wt.%) glass-ceramics were prepared by hot uniaxial pressing(HUP)and melt-quenching methods, respectively. The glass-ceramics with MIR emission bands greater than 1000 nm were successfully prepared by both methods. The effects of matrix glass composition and grain doping concentration on the optical properties of the samples were studied. The occurrence state, morphology of the grains, and the microscopic elemental distributions were characterized using x-ray diffraction(XRD), scanning electron microscope(SEM), and energy dispersive spectrometer(EDS) analyses.     

Single-mode low-loss chalcogenide glass waveguides for the mid-infrared

We demonstrate the design, fabrication, and characterization of single-mode low-loss waveguides for mid-infrared (MIR) wavelengths. Planar waveguide structures were fabricated from multilayer thin films of arsenic-based chalcogenide glasses followed by the creation of channel waveguides by using the photodarkening effect. Propagation losses as low as 0.5 dB/cm were measured for a quantum cascade laser end-fire coupled into the waveguides. This is a first step toward the design and fabrication of integrated optical components for MIR applications.     

Molding of soft glass refraction mini lens with hot embossing process for broadband infrared transmission systems

In this paper we report on the development of small-diameter lenses in soft glass with transmission in infrared till 5 μm using hot embossing method. A fused silica stamps and in-house synthesized tungsten–tellurium–niobate and lead–bismuth–galate glasses are used for replication. Optimization process of hot embossing is presented. Optical properties of replicated lenses were characterized. Resolution of 50 lp/mm is obtained.     

Freely adjusted properties in Ge–S based chalcogenide glasses with iodine incorporation

In this study, we examined the function of halogen iodine acting as a glass network modifier in green chalcogenide glasses based on the Ge–S system. We obtained a series of Ge–S–I glasses and determined their glass-forming region. We then recorded the physical, thermal, and optical properties and studied the effect of halogen iodine on Ge–S–I glasses. Results show that these glasses have relatively wide optical transmission window for infrared (IR) applications. The softening temperature of Ge–S–I glasses varies from 210.54 °C to 321.63 °C, this temperature fits well with some kinds of high-temperature polymers, such as PES and PEI, the polymers serve as protective layers with high strength and flexibility, thus simplifying the fabrication processes of IR chalcogenide glass fiber. Finally, we performed a purification process to eliminate impurities and to improve optical spectra.     

Time dependence of the polarization of the luminescence in chalcogenide glasses

Time dependence of the polarization of the luminescence with polarized exciting light and its temperature dependence were observed in chalcogenide glasses. The experimental data can be analyzed with a model based on localized excitons in a fluctuating potential due to random structure of the glasses.     

Superionic and ion-conducting chalcogenide glasses: Transport regimes and structural features

Chalcogenide glasses are essentially known as amorphous semiconductors with interesting electronic and optical properties. In contrast to vitreous oxide systems which belong mostly to ionic insulators and/or conductors, the ion transport is not common for chalcogenide glasses and was observed for the first time in the seventies. Nevertheless, a higher polarisability of sulphur, selenium or tellurium compared to oxygen and respectively a higher ionic mobility and diffusivity, makes appropriate chalcogenide glassy systems favourable candidates for both fundamental research and practical applications in the field of solid-state ionics. The observed drastically different ion transport regimes that are closely related to the mobile cation distribution in the structure of silver and copper chalcogenide and chalcohalide glasses will be discussed in the present contribution which represents a compilation of recent results obtained by the author.     

Photoinduced stable second-harmonic generation in chalcogenide glasses

We report on photoinduced second-harmonic generation (SHG) in chalcogenide glasses. Fundamental and second-harmonic waves from a nanosecond pulsed Nd:YAG laser were used to induce second-order nonlinearity in chalcogenide glasses. The magnitude of SHG in 20G?20A?60S glass was 10(4) larger than that of tellurite glass with a composition of 15Nb(2)O (5) 85TeO(2) (mol.%). Moreover, no apparent decay of photoinduced SHG in 20G?20A?60S glass was observed after optical poling at room temperature. We suggest that the large and stable value of chi((2)) is due to the induced defect structures and large chi((3)) of the chalcogenide glasses.     

Variable angle spectroscopic ellipsometry and its applications in determining optical constants of chalcogenide glasses in infrared

The principle of variable angle spectroscopic ellipsometry(VASE) and the data analysis models, as well as the applications of VASE in the characterization of chalcogenide bulk glasses and thin films are reviewed. By going through the literature and summarizing the application scopes of various analysis models, it is found that a combination of various models, rather than any single data analysis model, is ideal to characterize the optical constants of the chalcogenide bulk glasses and thin films over a wider wavelength range. While the reliable optical data in the mid-and far-infrared region are limited, the VASE is flexible and reliable to solve the issues, making it promising to characterize the optical properties of chalcogenide glasses.     

Concentration dependence of radiation-induced changes in the optical properties of Ge<Subscript>x</Subscript>As<Subscript>40−<Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>60</Subscript> films

Radiation-induced changes in the optical properties of chalcogenide glasses in the Ge-As-S system are investigated as a function of the concentration. Theoretical calculations are performed with due regard for possible constraints on the range of variation in the number of homobonds and heterobonds upon their switching in the structural network of chalcogenide glasses. The experimental data are obtained upon irradiation of Ge_xAs_40?xS₆₀ thin films with fast electrons (6 MeV). The possible mechanism of structural transformations responsible for the specific features in the concentration dependence of the change in the band gap of chalcogenide glasses is discussed.     

Recent advancement in metal containing multicomponent chalcogenide glasses

Amorphous semiconductors or chalcogenide glasses are the key materials in modern optoelectronics to make comfortable life of our society. Understanding of physical properties (like microstructure, thermal, optical, electrical) of these materials is important for their different uses. Predominant study of physical properties of the metal containing multicomponent chalcogenide glasses have attracted much attention, due to their interesting variable features and wide range of structural network modifications. Structural modifications in these materials are usually described with respect to the values of structural units (or average coordination number). In significance to this, the present work demonstrates the chronological development in the field of chalcogenide glasses along with scanning electron microscopy (SEM) morphologies. Optical, electrical and thermal correlative properties of recent developed Se_93?xZn₂Te₅In_x (0 ?? x ?? 10) metallic multicomponent chalcogenide glasses are discussed. Variation in SEM morphology, refractive index (n), extinction coefficient (K), optical energy band gap (E_g), electrical conductivity (??_av), crystallization activation energy (E_c) and glass forming ability (GFA) with structural units of Se-Zn-Te-In glasses have been demonstrated in this study. Subjected materials thermal, optical and electrical parameters have been achieved higher and lower in a respective manner at the threshold structural unit value ??r??.     

PbI2对远红外Te基硫系玻璃光学性能的影响

用传统的熔融淬冷法制备了一系列新型Ge-Te-PbI₂硫系玻璃,并且讨论了玻璃的形成区域. 利用X射线衍射(XRD)、差热分析(DTA)、可见/近红外吸收光谱、红外透过光谱等技术,研究重金属卤化物PbI₂对Ge-Te硫系玻璃组成、结构和性能的影响. 利用Tauc方程计算了样品的直接和间接光学带隙,根据金属标准和能量带隙理论讨论了玻璃光学带隙与组分变化的关系. 结果表明:PbI₂的引入,提高了Te玻璃的形成能力,而且玻璃的热稳定性良好;随着PbI₂含量的增加,玻璃的密度和折射率均增大,光学带隙减小,短波吸收截止边发生红移,玻璃的红外截止波长基本不变,达到了25 μm. 该系列玻璃可用于制备远红外长波波导器件. 关键词： Te基玻璃 2')" href="#">PbI₂ 光学带隙 红外光谱     

Chalcogenide glasses as a medium for controlling ultrashort IR pulses: Part I

Chalcogenide glasses are ideal materials for developing fiber lasers and amplifiers, remote sensors, high-speed switches, and other devices that operate in the IR range of 1–10 μm. The nonlinear refractive index of chalcogenide glasses may exceed that of quartz glass by a factor of 100–1200 or even more. The data on the dispersion properties of some chalcogenide glass compositions in the IR range are presented. The possibility of forming waveguide structures with specified dispersion properties (in particular with a fixed wavelength at which the group velocity dispersion is zero) from these glasses is numerically investigated. It is shown by the example of completely glassy periodic waveguide structures with planar geometry that the use of photonic band gap modes makes it possible the change the position of zero dispersion in a wide wavelength range. In the calculations the contrast of waveguide structures was varied using parameters of glasses of different composition.     

Middle-infrared chalcogenide glass fibers with losses lower than 100 db km−1

Optical losses and mechanical strength of chalcogenide glass fibers prepared by crucible technique are reported. Mechanisms of optical losses in the high-transparancy region of chalcogenide glasses are discussed.     

金属玻璃的热塑性成型

金属玻璃在其过冷液相区内表现出随着温度升高黏度逐渐降低的特性,因此可以对其进行热塑性加工.该性质颠覆了传统金属的加工成型方式,使得其在远低于传统金属材料加工的温度和应力作用下可以按照人们的要求进行成型.因此,一些具有低玻璃转变温度的金属玻璃又被称作金属塑料.另外,由于金属玻璃是一种无序结构材料,不存在位错、晶界等晶体缺陷,且热膨胀系数小,在热塑性成型中具有优异的尺寸精度,因此被认为是理想的微成型材料,有广阔的应用前景.本文系统介绍了金属玻璃的热塑性成型性质及其应用,从热塑性成型的基本概念出发,阐述了金属玻璃热塑性成型能力的评估指标、热塑性成型技术、热塑性微成型及其理论、热塑性微成型的应用等,对认识金属玻璃的热塑性及扩展其应用有重要的意义.     

Nonlinear Integrated Optical Waveguides in Chalcogenide Glasses

This paper reports on the study and measurement of the third order optical nonlinearity in bulk sulfide-based chalcogenide glasses; The fabrication process of the ultrafast laser deposited As-S-(Se)-based chalcogenide films and optical waveguides using two techniques: wet chemistry etching and plasma etching.     

非晶态半导体的缺陷态化学键的量子化学研究

用量子化学的半经验自洽场分子轨道方法CNDO/2研究硫属玻璃中的各种缺陷态,包括带正电荷、负电荷和中性的三配位硫原子簇的化学键。从原子簇能量、原子净电荷、键级函数(双原子能量)等方面作了比较,取得了与Kastner相一致的结果,验证了K-A-F的换价对(VAP)理论。探讨了孤对电子对于缺陷态化学键的影响,证实了孤对电子在硫属玻璃中的重要作用。 关键词：     

On the variation of activation energy for amorphous–crystallization phase transition in Se–Te–Sn chalcogenide glasses using iso-conversional analysis

In this paper, the variation of activation energy of amorphous–crystallization phase transition of as-Se_85–xTe₁₅Sn_x (x = 2, 4 and 6) chalcogenide glasses is investigated using iso-conversional analysis under non-isothermal conditions using differential scanning calorimetric (DSC) technique. The study is based on the variation of activation energy of crystallization with the degree of conversion and hence with temperature. The three iso-conversional methods of Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW) and Friedman are used to deduce the variation of activation energy with the extent of conversion and also with temperature. The KAS and OFW methods give the similar values while the Friedman method gives lower values of activation energy of crystallization for the investigated chalcogenide glasses.     

Compositional Trends of Radiation-Induced Effects in Ternary Systems of Chalcogenide Glasses

The effect of γ-irradiation on the optical transmittance spectra of pseudobinary stoichiometric and non-stoichiometric cuts of ternary systems of chalcogenide glasses was studied. The application of chemical-bond approach is proposed to explain the features of compositional dependencies of radiation-induced effects in these materials. It is shown that free volume concept must be taken into consideration at the presence of different radiation-sensitive structural units. The creation processes of coordination defects connected with the formation of free volume and coupled with the capability of the constituent atoms to passivation are the main factors determining the magnitude of the radiation-induced effects in chalcogenide glasses.     

On the super-linear frequency dependent conductivity of amorphous semiconductors

A super-linear frequency dependent conductivity has been observed experimentally in several amorphous semiconductors. An explanation for this behaviour is proposed, in particular for the case of chalcogenide glasses, where it is shown to be a consequence of a particular spatial probability distribution for charged centres. The fundamental mechanism for a.c. conduction in chalcogenide glasses is the same as that proposed previously; namely, the simultaneous hopping of two electrons over the barrier separating two oppositely charged centres, the barrier height being correlated with the intersite separation via the Coulomb interaction. It is demonstrated that this phenomenon should be most marked in those glasses having a large band-gap.