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![Illustration of the bond formation in GeTe and the resulting band structure. Atomic orbitals of Ge and Te responsible for bond formation in GeTe are depicted at the top. σ‐Bonds are formed from p-orbitals, which are occupied by about half an electron pair (ES ≈ 1), resulting in a metallic band (blue curves at the bottom of the figure). However, moderate charge transfer and/or a moderate Peierls distortions result in a small band gap. Modified after [25].](publication/364550343/figure/fig1/AS:11431281207866787@1701351622506/Illustration-of-the-bond-formation-in-GeTe-and-the-resulting-band-structure-Atomic.jpg)
Illustration of the bond formation in GeTe and the resulting band structure. Atomic orbitals of Ge and Te responsible for bond formation in GeTe are depicted at the top. σ‐Bonds are formed from p-orbitals, which are occupied by about half an electron pair (ES ≈ 1), resulting in a metallic band (blue curves at the bottom of the figure). However, moderate charge transfer and/or a moderate Peierls distortions result in a small band gap. Modified after [25].
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![From [37], the integration of theory databases, combinatorial libraries...](publication/364550343/figure/fig4/AS:11431281207866790@1701351623001/From-37-the-integration-of-theory-databases-combinatorial-libraries-and-imaging-is_Q320.jpg)
Alloys of sulphur, selenium and tellurium, often referred to as chalcogenide semiconductors offer a highly versatile, compositionally-controllable material platform for a variety of passive and active photonic applications. They are optically nonlinear, photoconductive materials with wide transmission windows that present various high- and low-inde...
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Citations
... In this work, we demonstrate a systematic waveguide loss reduction study on Ge 28 Sb 12 Se 60 (GeSbSe) chalcogenide glass. Chalcogenide glass exhibits an extremely wide transparency window through the near-IR all the way to the long-wave IR [14][15][16][17][18] and is considered a practical waveguide material for mid-IR photonics. To date, there are several reports on lowloss chalcogenide glass waveguides with various compositions [19][20][21][22][23]. Compared with them, GeSbSe is highly nonlinear (vs. ...
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.
... Chalcogenide glasses (ChGs) have received a great deal of attention in recent decades with its excellent infrared and nonlinear optical properties [1][2][3][4][5] in the area of integrated photonics [6][7][8][9][10], supercontinuum sources [11][12][13][14], and alloptical switches [15][16][17]. Among them, many kinds of ChGsbased all optical switches are fabricated and experimentally studied, and the switching power as low as 105 MW cm −1 was obtained due to the large nonlinearity, which was approximately 200 times lower than that of silica [16]. ...
Chalcogenide glass is an important nonlinear optical material that has attracted much attention in the areas of integrated photonics, supercontinuum sources, and all-optical switches in recent years. However, the current research mainly focuses on the nonlinear effect excited by light, and the research on its properties under the action of a DC field is still deficient. Here, a metal-cladding optical waveguide, which is composed of a chalcogenide glass film coated on a glass substrate, is presented to analyze the quadratic electro-optic (QEO) effect of the chalcogenide glass film. The DC Kerr coefficient and the whole components of the QEO tensor of the sample were experimentally determined by the free space coupling method.
... The exceptional electronic and optical properties of transition metal dichalcogenide (TMDC) monolayers have made them promising candidates for integrated electronics, optics, and photonics [1][2][3][4][5]. The mechanical flexibility of these two-dimensional sheets additionally enables the manipulation of their intrinsic features through deposition on nanostructured substrates [6][7][8][9] where significant deformations may occur giving rise to peculiar topologies [10][11][12], such as nanobubbles [13][14][15] or nanowrinkles [16]. ...
Mechanical deformations, either spontaneously occurring during sample preparation or purposely induced in their nanoscale manipulation, drastically affect the electronic and optical properties of transition metal dichalcogenide monolayers. In this first-principles...
... These amorphous materials represent a real boon for the whole range of passive and active photonic applications within the traditional and emerging technology platforms. 1 Chalcogenide glasses can be shaped in a variety of ways: in addition to the basic synthesis generally obtained by conventional melting−quenching, the use of mechanical milling is becoming more widespread, 2 various fiber-drawing techniques have also been developed, and the manufacture of amorphous films is essentially carried out via physical vapor deposition (PVD) methods. More recently, the additive manufacturing approach is also being explored, via the formulation of nanoparticle-based inks and inkjet printing for the deposition of thin films or 3D printing based on thin glass rods. ...
In this paper, we report on the infrared luminescence of amorphous praseodymium-doped
Ge20In5Sb10Se65 waveguides, which can be used as infrared sources in photonic integrated circuits on
silicon substrates. Amorphous chalcogenide thin films were deposited by radiofrequency magnetron
cosputtering using an argon plasma whose deposition parameters were optimized for chalcogenide
materials. The micropatterning as ridge waveguides of the chalcogenide cosputtered films was performed
using photolithography and plasma-coupled reactive ion etching techniques. The influence of the rare
earth concentration within those thin films on their optical properties and rare earth spectroscopic
properties was investigated. Using an excitation wavelength of 1.55 μm, the mid-infrared luminescence of Pr3+ ions from 2.5 to 5.5
μm was clearly demonstrated for studied chalcogenide materials. A wide range of waveguide widths and doping ratios were tested,
assessing the ability of the cosputtering technique to preserve the luminescence properties of the rare earth ions initially observed in
the bulk glass through the thin-film deposition and patterning process.
... Most importantly, chalcogenides exhibit non-volatile switching in the form of phase change and photo-ionic effects [22,23]. The former involves switching between an amorphous and crystalline state using optical, electrical, or thermal stimuli [23][24][25][26] and has been widely exploited in optical disk (Blurays and DVD's) and phase change random access memory (PCRAM) technology for decades. The amorphous-to-crystalline transition in chalcogenides is an annealing process that can be initiated by increasing the ambient temperature or locally by laser-or electrical current-induced heating to a temperature above the alloy's glass-transition point, T g (∼160°C for GST), but below its melting point, Tm (∼600°C). ...
In photonic integrated circuits, efficient coupling of light between fibers and waveguides is challenging due to mode area mismatch. In-plane grating couplers (GC) have become popular for their low cost, easy alignment, and design flexibility. While most GC designs have fixed coupling efficiencies, with a view to emerging adaptive neuromorphic and quantum integrated circuits and interposers that need ultra-compact memory/modulation components, we introduce a CMOS-compatible GC based on phase-change chalcogenide alloy germanium antimony telluride. The GC design optimized utilizing inverse design techniques achieves over 50% coupling efficiency at 1550 nm when amorphous, and near-zero efficiency when switched to a crystalline state. This design is non-volatile, reversible, and provides ultra-high transmission modulation contrasts of up to 60 dB. While the operational range can be adjusted across the telecommunication band by modifying the GC's etch depth or thickness. We show that such devices do not need global switching of their entire phase change volume and can achieve maximum modulation contrasts through switching precisely positioned phase change inclusions hinting at low-power and ultrafast modulation potential.
... The chalcogenide materials are characterized by a record-high acousto-optic coefficient. Just recently, the authors of [39] presented the road map for emerging photonic technology platforms. Chalcogenide semiconductors play a critical role in this architecture. ...
The paper is a review of surface plasmon resonance (SPR) structures containing amorphous chalcogenide (ChG) films as plasmonic waveguides. The calculation method and specific characteristics obtained for four-layer SPR structures containing films made of amorphous As2S3 and As2Se3 are presented. The paper is mainly based on our previously obtained and published scattered results, to which a generalized point of view was applied. In our analysis, we demonstrate that, through proper choice of the SPR structure layer parameters, we can control the resonance angle, the sharpness of the SPR resonance curve, the penetration depth, and the sensitivity to changes in the refractive index of the analyte. These results are obtained by operating with the thickness of the ChG film and the parameters of the coupling prism. Aspects regarding the realization of the coupling prism are discussed. Two distinct cases are analyzed: first, when the prism is made of material with a refractive index higher than that of the waveguide material; second, when the prism is made of material with a lower refractive index. We demonstrated experimentally that the change in reflectance self-induced by the modification in As2S3 refractive index exhibits a hysteresis loop. We present specific results regarding the identification of alcohols, hydrocarbons, and the marker of E. coli bacteria.
... In this process, the refractive index of GST in particular will change dramatically and reversibly, making the difference in refractive index between crystalline and amorphous states of the material, so that different optical effects can be achieved [20]. In our work at the telecommunication wavelength (λ ≈ 1550 nm), the refractive index of amorphous GST (a-GST) is set to n a (= 3.88 + 0.016i) with less loss, while crystalline GST (c-GST) has a larger loss with a refractive index of n c (= 6.09 + 0.83i) [21]. ...
For effective wavefront management in the optical infrared range, dynamic all-dielectric metasurfaces, always based on phase transition materials, particularly ${{\rm Ge}_2}{{\rm Sb}_2}{{\rm Te}_5}$ G e 2 S b 2 T e 5 (GST), can be used. In this paper, we propose a GST-based tunable metasurface by structuring the phase-change material GST. We confirm that the nanopillar we designed has high transmittance in the wavelength band around 1550 nm and can fully cover the ${0}\sim{2}\pi$ 0 ∼ 2 π phase. Based on these characteristics, we can achieve beam steering and a focusing effect in amorphous phase by elaborately arranging GST nanopillars, while the aforementioned optical phenomena disappear in crystalline phase. Additionally, by arranging the array of vortex phases, we also realize switching the perfect composite vortex beam (PCVB) when changing the crystal state of GST, and simulate the generation of PCVB with different topological charges and sizes in amorphous phase. We believe that our research results can serve as a reference for multifunctional optical surfaces, dynamic optical control, optical communication, and information processing.
... 25 It is thus of great interest to develop the chalcogenide perovskites as a novel family of materials for optoelectronic applications. 26 The II−IV chalcogenide perovskites ABS 3 with A = Ca, Sr, or Ba and B = Zr or Hf are the most widely studied so far. 12,16−18,27−30 Further enrichment of the family could be achieved by exploring other groups of elements at both the cation and anion sites. ...
The highly promising linear and nonlinear optical properties of innovative thin films of GeSe 1– x Te x chalcogenide materials in the amorphous as‐deposited state, and after crystallization, are revealed here. These innovative alloys bridge the gap between two families of materials: chalcogenide glasses (GeSe) and phase‐change materials (GeTe). Their unique optical properties make them attractive candidates for reconfigurable and nonlinear photonic applications in the infrared. In this context, it is shown how, by varying the Te content of GeSe 1– x Te x thin films, it is possible to tailor their linear and nonlinear optical properties to optimize them for a wide range of innovative applications.
