Se Chalcogenide Glasses Research Articles

Octave spanning and flat-top supercontinuum generation in standard foundry-compatible process-made Ge–Sb–Se chalcogenide glass waveguide

We reported near octave-spanning supercontinuum generation in Ge28Sb12Se60 chalcogenide glass rib waveguides. The waveguides were fabricated using foundry-compatible deep ultra-violet lithography, followed by plasma etching. We demonstrated an average propagation loss of ∼1.3 dB/cm at the 1550 nm telecommunication wavelength. With dispersion engineering, optimizing waveguide geometry, and pumping by a multi-wavelength femtosecond soliton fiber laser, we achieved a flat-top supercontinuum generation spanning from 1290 to 2400 nm and beyond . It has a 3 dB bandwidth of 436 nm and a 20 dB bandwidth of more than 900 nm. The implementation of such waveguides provides a practical broadband light source solution for on-chip spectroscopy and sensing systems.

Study of Raman scattering in As–Se chalcogenide glasses by applying of partial pair correlation functions

Study of Raman scattering in As–Se chalcogenide glasses by applying of partial pair correlation functions

Mitigating waveguide loss in Ge–Sb–Se chalcogenide glass photonics

Minimizing propagation loss within waveguides remains a central objective across diverse photonic platforms, impacting both linear lightwave transmission and nonlinear wavelength conversion efficiencies. Here, we present a method to mitigate waveguide loss in Ge28Sb12Se60 chalcogenide glass, a material known for its high nonlinearity, broad mid-infrared transparency, and significant potential for mid-IR photonics applications. By applying a sacrifical oxide layer to eliminate etching residues and a subsequent waveguide thermal reflow to smooth lithography-induced line edge roughness, we successfully reduced the waveguide loss down to 0.8 dB cm−1 at 1550 nm wavelength. This represents the best result in small-core and high-index-contrast Ge28Sb12Se60 channel waveguides. Our approach paves the way for low-loss, on-chip chalcogenide photonic devices.

Multilayered chalcogenide glass with gradient index for reduced SWaP IR optical system

Gradient index (GRIN) lens could promote the lightweight and miniaturization of optical imaging system, but the development of IR GRIN lens is still in its infancy. A new series of As–S–Se chalcogenide glasses (ChGs) possessing similar glass transition temperature, excellent thermal stability, and large refractive index variation was developed, and these properties enabled them to become a good glass material catalog for co-molding multilayered GRIN IR lens. By employing precision molding, layer-stacked GRIN ChG was co-molded with a maximum refractive index variation of 0.47 at 4 μm, which was correlated to the variation of Raman intensity and elemental content. A mid-IR optical imaging system was designed and fabricated using the GRIN ChGs, and IR images were obtained. This multilayered GRIN ChG could lead to 18% smaller and 35% lighter SWaP IR optical system.

The Crystallization Behavior of As–S–Se Chalcogenide Glass with Small Amounts of Arsenic

The Crystallization Behavior of As–S–Se Chalcogenide Glass with Small Amounts of Arsenic

Low-loss single-mode Ge–As–S–Se glass fiber and its supercontinuum generation for mid-infrared

We report broadband supercontinuum (SC) spectra generated from low-loss single-mode fibers (SMF) based on novel Ge–As–S–Se (GASS) chalcogenide (ChGs) glasses. The step-index fibers (SIF) possess an ultra-low background loss of 0.27 dB/m at wavelength of 2.5 ∼7.5μm were fabricated by an optimized peeled-off extrusion method. SC generation was studied by pumping the fiber with 15 cm and 100 cm at same condition (5μm, ∼150 fs, 1 kHz, 25 mW), respectively. Output SC covering 1.46 ∼9.32μm was obtained in this 15-cm fiber, while a relatively wide output SC spanning from 1.68 to 8.28μm was observed in 100-cm fiber. Due to simulated numerical model does not account for higher-order modes at shorter wavelengths, cladding modes, polarization effects etc. Experimental SC spectral profile in the short and long S/Se fibers is slightly different with the simulation analysis. To the best of our knowledge, this is the first report on the performance of GASS fiber.

Erbium-doped GeSbSe glassy semiconductors and theoretical analysis of constraint, electronic and thermal properties

ABSTRACT Erbium-doped Ge–Sb–Se (GSS) chalcogenide glasses have potential applications in environment sensing and are good candidates for mid-infrared (IR) laser. This article includes the theoretical study of Ge17Sb8Se75-x Er x (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) chalcogenide system for physical parameters. The physical parameters include the calculation of the average coordination number, total number of constraints, electron lone pair, mean bond energy, glass transition temperature, packing fraction, deviation from stoichiometry, cohesive energy (CE) and energy band gap. It is observed that the average coordination number, total constraints, lone pair of electrons, mean bond energy and CE increase on increasing the erbium content, while the deviation from stoichiometry and band gap decrease. The covalent character of the alloy is more than 90% which suggests the system can form stable glasses and may be explored for IR application.

High-performance acousto-optic modulator based on environmentally favorable Ge20Sb15Se65 chalcogenide glass

Acousto-optic (AO) properties of an environmentally friendly Ge20Sb15Se65 chalcogenide glass were investigated, and the results show that Ge20Sb15Se65 glass was a potential material for manufacturing AO modulator (AOM) because its composition possesses excellent performance of high optical quality and transmission in the infrared region spectral, non-toxic, high glass transition temperature, strong mechanical strength, easy to fabricate in large bulk, and isotropic homogeneity. Particularly, its outstanding AO figure of merit (M2 = 407 × 10−15 s3/kg) was approximately 270 times that of fused quartz glass, making it attractive for AO device designs. Herein, the construction of the AOM based on Ge20Sb15Se65 glass as AO material was performed, and we obtained a high diffraction efficiency of 73.4% at a high acoustic frequency of 160 MHz and an extremely low radio-frequency (RF) power of 0.25 W when the laser beam at 1550 nm was controlled. To our best knowledge, the results of initial tests on the AOM prepared from Ge–Sb–Se chalcogenide glass were first reported. Such an AOM design enriches the family of AO devices and exploits the route for the practical application of chalcogenide glass.

Investigation of the acousto‐optical properties of Ge–As–Te–(Se) chalcogenide glasses at 10.6 μm wavelength

AbstractThe acousto‐optic parameters of Ge10As90−xTex (x = 30, 40, 50, 60, 70 mol%) and Ge10As20Te70−ySey (y = 20, 30, 40, 50 mol%) glasses, were studied systematically to compare the pros and cons of Te‐based and Se‐based chalcogenide glasses in acousto‐optic performance, as well as the thermomechanical properties. In the Ge10As90−xTex system, the acousto‐optic figure of merit (M2) increased with increased Te content, and the maximum M2 of 2279 × 10−18 s3/g, which is 13 times that of commercial single‐crystal Ge, obtained in Ge10As20Te70 at 10.6 μm. However, its thermal properties and elastic modulus decreased and the acoustic attenuation (α) at different ultrasonic frequencies increased accordingly. In the Ge10As20Te70−ySey system, the thermomechanical performance of the glasses improved with the introduction of Se element, the overall α was lower than that of Te‐based chalcogenide glasses, and the minimum α was 5.29 dB/cm at 30 MHz ultrasonic frequency, although its M2 was inferior to that of Te‐based chalcogenide glasses. Additionally, the difference in the α of these glasses was smaller at low ultrasonic frequencies than at high ultrasonic frequencies. This work will promote the practical application of chalcogenide glasses as promising materials with outstanding acousto‐optic properties in low ultrasonic frequency acousto‐optic devices.

Ag-doped As–S–Se chalcogenide glasses: a correlative study of structural and dielectrical properties

This work is focused on investigating the effect of Ag doping on the dielectric and structural properties of the As–S–Se glass system and their suitability for potential applications in optoelectronics, such as electronic and switching components. A series of glasses from the system Agx(As40S30Se30)100−x (x ≤ 5 at.% Ag) were prepared with melt-quenching technique. Morphological and compositional analysis was performed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Raman spectroscopy measurements have shown structural modifications of the glass network upon Ag doping, with creation of new Ag–(S,Se)–As structures, resulting in increased number of defect states. Variations in dielectric permittivity (e′) and dielectric loss (e″) were investigated in a wide frequency and temperature range, and explained by dominant dipolar and electronic polarization, as well as correlated with the observed structural changes. Improvement in dielectric properties is observed upon doping with Ag. Furthermore, the low dielectric tangent loss at high frequencies for all glassy samples points to a beneficial ability of the material to absorb energy of the external electric field. Good thermal stability of these glasses is confirmed by the calculated temperature coefficient of the dielectric permittivity. Density of localized states in all glasses was determined from AC conductivity and the dielectric tangent loss using a correlated barrier hopping model, and found to increase with Ag concentration. The overall results suggest that Ag doping enhances the electrical and optical quality of this type of glasses, making them suitable as nonlinear optical materials and their applications in devices.

Phase change in Ge–Se chalcogenide glasses and its implications on optical temperature-sensing devices

Reversible amorphous to crystalline phase transition introduces high contrast in the optical and electrical properties of chalcogenide glasses. This effect can be utilized by a designated temperature sensor based on optical power measurement as a function of temperature for temperature monitoring. For this purpose, crystallization kinetics and crystal structures of Ge–Se binary chalcogenide glasses were studied with Differential Scanning Calorimetry, Raman spectroscopy, and X-ray diffraction spectroscopy. The refractive index as a function of temperature was also measured to correlate the effect of structural rearrangement at the phase transition point with optical properties. Based on these data, the crystallization process is interpreted as being homogeneous for the stoichiometric composition and heterogeneous for either chalcogenide- or germanium-rich compositions. This specifically affects the optical performance of the films as a function of temperature and suggests the application of chalcogen- or germanium-rich compositions for building the sensor.

Ultra-high germanium-contained Se-chalcogenide glass fiber for mid-infrared

A chemically stoichiometric chalcogenide (ChG) glass fiber with ultra-high germanium-containing has been realized for the first time. Here, an isolated extrusion (ISE) with a peeled-off method was carried out for the fiber fabrication with glasses of core Ge33As12.5Se54.5 and cladding Ge33As12Se55. The fiber exhibits an optical loss of < 3 dB/m in a range of 5.1–7.9 μm, and the minimum loss of 2.11 dB/m was obtained at 6.61 μm. For SC generation, The broadest spectrum from 1.66 to 11.40 μm at − 30 dB was achieved in the 13 cm-long fiber pumped by 5 μm laser with pump power of 25 mW. This fiber possesses the potential applications of high power laser generation and transmission.

Fabrication, characterization and the effects of femtosecond laser ablation on Te–As–Se glasses

Te–As–Se (TAS) chalcogenide (ChG) glasses have broad transmission range of up to 18 μm and are suitable candidates for mid-infrared (MIR) applications. In this work, TAS glasses were synthesized via melt-quenching technique. Glass-forming domain was determined by X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Optical properties and structural information were recorded. A series of glasses with compositions of TexAs40Se60-x (x == 0, 10, 20, 30, 40, 50, in mol%) was irradiated by 3 μm femtosecond (fs) laser with different powers. The morphology and structural information after laser ablation were then studied via scanning electron microscopy (SEM) and Raman technique. The laser damage threshold decreased from 29.45 mJ/cm2 to 21.93 mJ/cm2 with the increase in Te contents in the TexAs40Se60-x glasses. This study is of great importance in supercontinuum (SC) generation and infrared laser transmission based on TAS fibers in the MIR range.

Surface damage and threshold determination of Ge–As–Se glasses in femtosecond pulsed laser micromachining

AbstractGe–As–Se chalcogenide glasses were prepared and the surface damage characteristics under femtosecond laser irradiation were experimentally investigated. Femtosecond laser beams with different power intensities, focusing depths, pulse repetition rates, and pulse numbers were employed to determine the damage thresholds of the samples. The surface morphologies and feature sizes of the damage craters were studied with regard to laser energy density to evaluate the damage circumstances of the glasses. The generation of the surface damage was also recorded by using different numbers of pulses. Results showed that the damage area increased monotonically with the laser power at low energy density and tended to saturation when reaching a critical value. According to the linear circumstances of laser energy density on the damage crater area, the average damage thresholds of the Ge–As–Se glasses with different repetition rates and pulse numbers were obtained. Results showed that the damage threshold decreased with the increase in pulse repetition rate and number of pulse.

Low gallium‐content, dysprosium III‐doped, Ge–As–Ga–Se chalcogenide glasses for active mid‐infrared fiber optics

AbstractA systematic investigation is presented, for the first time, of a 1000 ppmw (parts per million, by weight) Dy3+‐doped Ge–As–Ga–Se chalcogenide glass series, with a fixed low Ga content of 1 atomic% (at. %), suitable for active mid‐infrared fiber optics. Seven glasses constitute the series, which have increasing average coordination number from 2.49 to 2.61, in steps of 0.02, with the GeSe2, As2Se3, and Ga2Se3 stoichiometries kept. Glass formation is confirmed using X‐ray diffraction and differential scanning calorimetry. Fourier transform infrared spectroscopy is reported for the series. Parallel plate viscometry enables prediction of fiber‐drawing temperatures and, with differential thermal analysis, determines the potential for fiber fabrication. X‐ray diffraction of samples after parallel‐plate viscometry shows that Ge25As9Ga1Se65 (at. %) alone, in the glass‐series, devitrifies to form the single‐crystalline phase: monoclinic‐GeSe2; scanning electron microscope imaging suggests that this phase is both surface and bulk grown. Overall, the recommended host glass at. % compositions for doping with rare‐earth ions and drawing to active mid‐infrared fiber are: Ge17.5As18Ga1Se63.5, Ge15As21Ga1Se63, and Ge12.5As24Ga1Se62.5.

Correlation among Structure, Water Peak Absorption, and Femtosecond Laser Ablation Properties of Ge–Sb–Se Chalcogenide Glasses

A series of Ge11.5SbxSe88.5–x (x = 5, 10, 15, 20, 25, 30) chalcogenide glasses were fabricated aiming at investigating the role of structure and water peak absorption in determining femtosecond laser ablation thresholds (Fth). The results indicate that the optical band gap decreases and that the Vickers hardness increases with increasing Sb content. Meanwhile, Raman spectra were measured before the femtosecond laser ablation experiment, suggesting a rise in average bond energy in the six glass samples with increasing Sb concentration. Ablation of the sample disks in air were performed with high repetition rate ultrashort laser pulses (150 fs, 1 kHz) at different wavelengths (2.86 and 4 μm) to investigate how the water peak absorption coefficient affects ablation thresholds, which reveals the dominating role of the multiphoton ionization (MPI) progress on the ablation threshold fluence. The results will be useful for photonic devices based on Ge–Sb–Se glasses applied in high-power laser operations to preve...

Effect of Ag addition on crystallization kinetics and thermal stability of As–Se chalcogenide glasses

Chalcogenide glasses of (As50Se50)100−xAgx (0 ≤ x ≤ 25) were prepared using the melt quenching technique under non-isothermal conditions. Differential scanning calorimetry curves measured at different heating rates (5 ≤ β ≤ 40 K min−1) are used to characterize the as-quenched samples. The thermal stability was monitored through the calculation of the temperature difference T c − T g, stability parameter S and crystallization rate factor K p. The glass-forming ability (GFA) was investigated on the basis of Hurby parameter H r which is a strong indicator of GFA. In addition, the activation energy of glass transition E t, activation energy of crystallization E c and Avrami exponent n of the studied compositions were determined. The mechanism of crystallization was found to be a combination of two- and three-dimensional crystal growth.

Structures of Ge15Sb x Se85−x chalcogenide glasses affect their Raman gain performance

A series of Ge15Sb x Se85−x (x = 5, 10, 15, 20, 25, and 30 mol%) chalcogenide glasses were prepared by traditional melt-quenching method. The refractive indexes, infrared transmissions, and spontaneous Raman spectra of the glass samples were measured. Based on the spontaneous Raman scattering theory and considering the measured Raman spectral data, we calculated the Raman gain coefficients of the chalcogenide glasses. The effect of Sb on the structures and Raman gain coefficients of the glass samples was then systematically investigated to understand the role of chemical composition in glass structure and Raman gain coefficient. In the Ge15Sb x Se85−x glasses, the number of heteropolar Ge–Se, Sb–Se bonds increased, whereas that of homopolar Se–Se bonds decreased at increased Sb concentration. The Raman gain coefficients increased until it reached a maximum value (290 × 10−13 m/W at Ge15Sb20Se65) and then decreased when the Sb concentration further increased. These results showed that the Raman gain coefficients of Ge–Sb–Se chalcogenide glasses without poisonous elements were over 300 times of that of commonly fused silica and closely correlated with the structures of the glasses, suggesting that the Raman gain coefficient can be adjusted by modifying the structures of the glasses. This work provides a new possibility for environment-friendly Raman fiber laser and amplifier materials.

Laser Desorption Ionization Time‐of‐Flight Mass Spectrometry of Glasses and Amorphous Films from Ge–As–Se System

Laser Desorption Ionization Time‐of‐Flight Mass Spectrometry was exploited for the characterization of Ge–As–Se chalcogenide glasses and corresponding thin films fabricated using pulsed laser deposition. Main achievement of the paper is the determination of laser generated clusters’ stoichiometry. The clusters observed were Asb+ (b = 1–3), Se2−, binary AsbSe+ (b = 1–3), AsbSec− (b = 1–3, c = 1–4), Ge2Sec− (c = 2–3), As3Se2+, Ge2Asb− (b = 2–3), Ge3Asb− (b = 1–2), Ge3Se4−, As5Sec− (c = 4–5), GeAsSe4−, GeaAsSe5− (a = 1–4), GeAs2Se3−, GeAs3Se2−, Ge2As2Se2−, Ge2AsSec− (c = 6–7), and GeAs3Sec− (c = 5–6) (in positive as well as in negative ion mode). The stoichiometries of identified species are compared with the structural units of the glasses/thin films revealed via Raman scattering spectra analysis. Some species are suggested to be fragments of bulk glass as well as thin films. Described method is useful also for the evaluation of the contamination of chalcogenide glasses or their thin films.

Development of thermally stable and moldable chalcogenide glass for flexible infrared lenses

Abstract