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Femtosecond Laser Direct Writing of Gradient Index Fresnel Lens in GeS2-Based Chalcogenide Glass for Imaging Applications. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12094490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Chalcogenide glasses have attracted growing interest for their potential to meet the demands of photonic applications in the Mid-Wavelength InfraRed (MWIR) and Long-Wavelength InfraRed (LWIR) transmission windows. In this work, we investigated the photosensitivity to femtosecond laser irradiation of a dedicated chalcogenide glass, along with its possible applications in micro-optics. In order to address the SWaP problem (Size, Weight and Power), this work took advantage of recent techniques in femtosecond laser direct writing to imprint flat and integrated optical systems. Here, we wanted to simplify an infrared multispectral imaging system which combines a lens array and a filter array. Each channel has a focal length of 7 mm and an f-number of 4. We show in this paper that the chosen GeS2-based chalcogenide glass is very promising for the fabrication of graded index optics by fs-laser writing, and particularly for the fabrication of Fresnel lenses. We note a very important phase variation capacity in this infrared material corresponding to refractive index variations up to +0.055. A prototype of Fresnel GRIN lens with a refractive index gradient was fabricated and optically characterized in the Vis range.
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Tverjanovich A, Khomenko M, Bereznev S, Fontanari D, Sokolov A, Usuki T, Ohara K, Le Coq D, Masselin P, Bychkov E. Glassy GaS: transparent and unusually rigid thin films for visible to mid-IR memory applications. Phys Chem Chem Phys 2020; 22:25560-25573. [PMID: 33146174 DOI: 10.1039/d0cp04697c] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phase-change materials based on tellurides are widely used for optical storage (DVD and Blu-ray disks), non-volatile random access memories and for development of neuromorphic computing. Narrow-gap tellurides are intrinsically limited in the telecom spectral window, where materials having a wider gap are needed. Here we show that gallium sulfide GaS thin films prepared by pulsed laser deposition reveal good transparency from the visible to the mid-IR spectral range with optical gap Eg = 2.34 eV, high refractive index nR = 2.50 over the 0.8 ≤ λ ≤ 2.5 μm range and, unlike canonical chalcogenide glasses, the absence of photo-structural transformations with a laser-induced peak power density damage threshold above 1.4 TW cm-2 at 780 nm. The origin of the excellent damage threshold under a high-power laser and UV light irradiation resides in the rigid tetrahedral structure of vitreous GaS studied by high-energy X-ray diffraction and Raman spectroscopy and supported by first-principles simulations. The average local coordination number appears to be m = 3.44, well above the optimal connectivity, 2.4 ≤ m ≤ 2.7, and the total volume of microscopic voids and cavities is 34.4%, that is, lower than for the vast majority of binary sulfide glasses. The glass-crystal phase transition in gallium sulfide thin films may be accompanied by a drastic change in the nonlinear optical properties, opening up a new dimension for memory applications in the visible to mid-IR spectral ranges.
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Affiliation(s)
- Andrey Tverjanovich
- Institute of Chemistry, St. Petersburg State University, 198504 St. Petersburg, Russia
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Lapointe J, Bérubé JP, Ledemi Y, Dupont A, Fortin V, Messaddeq Y, Vallée R. Nonlinear increase, invisibility, and sign inversion of a localized fs-laser-induced refractive index change in crystals and glasses. LIGHT, SCIENCE & APPLICATIONS 2020; 9:64. [PMID: 32351688 PMCID: PMC7171118 DOI: 10.1038/s41377-020-0298-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/20/2020] [Accepted: 03/19/2020] [Indexed: 05/14/2023]
Abstract
Multiphoton absorption via ultrafast laser focusing is the only technology that allows a three-dimensional structural modification of transparent materials. However, the magnitude of the refractive index change is rather limited, preventing the technology from being a tool of choice for the manufacture of compact photonic integrated circuits. We propose to address this issue by employing a femtosecond-laser-induced electronic band-gap shift (FLIBGS), which has an exponential impact on the refractive index change for propagating wavelengths approaching the material electronic resonance, as predicted by the Kramers-Kronig relations. Supported by theoretical calculations, based on a modified Sellmeier equation, the Tauc law, and waveguide bend loss calculations, we experimentally show that several applications could take advantage of this phenomenon. First, we demonstrate waveguide bends down to a submillimeter radius, which is of great interest for higher-density integration of fs-laser-written quantum and photonic circuits. We also demonstrate that the refractive index contrast can be switched from negative to positive, allowing direct waveguide inscription in crystals. Finally, the effect of the FLIBGS can compensate for the fs-laser-induced negative refractive index change, resulting in a zero refractive index change at specific wavelengths, paving the way for new invisibility applications.
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Affiliation(s)
- Jerome Lapointe
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Jean-Philippe Bérubé
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Yannick Ledemi
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Albert Dupont
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Vincent Fortin
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Younes Messaddeq
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Réal Vallée
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
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Li CC, Wang B, Chen D, Gan LY, Feng Y, Zhang Y, Yang Y, Geng H, Rui X, Yu Y. Topotactic Transformation Synthesis of 2D Ultrathin GeS 2 Nanosheets toward High-Rate and High-Energy-Density Sodium-Ion Half/Full Batteries. ACS NANO 2020; 14:531-540. [PMID: 31846288 DOI: 10.1021/acsnano.9b06855] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Currently, development of metal sulfide anodes for sodium-ion batteries (SIBs) with high capacity, fast charging/discharging, and good cycling performance continues to present a great challenge. Hence, a topochemical conversion strategy is reported to fabricate 2D ultrathin GeS2 nanosheets (thickness: ∼1.2 nm) as the potential anodes for sodium storage. The 2D ultrathin nanostructure can mitigate the electrode-electrolyte contact issue faced by bulk material and provide shorter transport/diffusion pathways for Na ions and electrons, resulting in excellent rate performance. Impressively, ultrathin GeS2 nanosheets can bring a large capacity of 515 mAh g-1 even after 2000 cycles under 10 A g-1. Additionally, as revealed by calculations and in situ/ex situ technique analysis, a favorable mechanism of Na+ intercalation/deintercalation into/from the GeS2 interlayer region (GeS2 ↔ NaxGeS2) is demonstrated. Furthermore, when coupled with the advanced cathode of Na3V2(PO4)2O2F, the sodium-ion full cell shows a stable high energy density (213 Wh kg-1), which makes our ultrathin GeS2 nanosheets a promising candidate for SIBs.
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Affiliation(s)
- Cheng Chao Li
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Bo Wang
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Dong Chen
- Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices, Collaborative Innovation Center of Advanced Energy Materials, School of Materials and Energy , Guangdong University of Technology , Guangzhou 510006 , China
| | - Li-Yong Gan
- Institute for Structure and Function and Department of Physics , Chongqing University , Chongqing 400030 , China
| | - Yuezhan Feng
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education , Zhengzhou University , Zhengzhou 450002 , China
| | - Yufei Zhang
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Yang Yang
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Hongbo Geng
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Xianhong Rui
- Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices, Collaborative Innovation Center of Advanced Energy Materials, School of Materials and Energy , Guangdong University of Technology , Guangzhou 510006 , China
| | - Yan Yu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science and Engineering , University of Science and Technology of China, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences (CAS) , Hefei , Anhui 230026 , China
- State Key Laboratory of Fire Science , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Dalian National Laboratory for Clean Energy (DNL) , Chinese Academy of Sciences (CAS) , Dalian 116023 , China
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Bérubé JP, Lapointe J, Dupont A, Bernier M, Vallée R. Femtosecond laser inscription of depressed cladding single-mode mid-infrared waveguides in sapphire. OPTICS LETTERS 2019; 44:37-40. [PMID: 30645539 DOI: 10.1364/ol.44.000037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 11/24/2018] [Indexed: 05/27/2023]
Abstract
Mid-infrared optical waveguides were inscribed in sapphire with femtosecond pulses at 515 nm. We show that such pulses induce a smooth negative refractive index change allowing for the inscription of a depressed cladding waveguide by closely overlapping the corresponding type I modification traces. The resulting structure consists of a highly symmetrical, uniform, and homogeneous waveguide. The size and numerical aperture of the waveguides were tailored to achieve efficient transmission in the mid-infrared. Single mode operation at a wavelength of 2850 nm and propagation loss of <0.37 dB/cm are reported for a 33 mm long depressed cladding waveguide. Thermal annealing was performed, and the refractive index contrast was still preserved to 50% (i.e., Δn=∼2.5×10-3) up to 1400°C.
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Bélanger E, Bérubé JP, de Dorlodot B, Marquet P, Vallée R. Comparative study of quantitative phase imaging techniques for refractometry of optical waveguides. OPTICS EXPRESS 2018; 26:17498-17510. [PMID: 30119561 DOI: 10.1364/oe.26.017498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A comparative study of quantitative phase imaging techniques for refractometry of optical waveguides is presented. Three techniques were examined: a method based on the transport-of-intensity equation, quadri-wave lateral shearing interferometry and digital holographic microscopy. The refractive index profile of a SMF-28 optical fiber was thoroughly characterized and served as a gold standard to assess the accuracy and precision of the phase imaging methods. Optical waveguides were inscribed in an Eagle2000 glass chip using a femtosecond laser and used to evaluate the sensitivity limit of these phase imaging approaches. It is shown that all three techniques provide accurate, repeatable and sensitive refractive index measurements. Using these phase imaging methods, we report a comprehensive map of the photosensitivity to femtosecond pulses of Eagle2000 glass. Finally, the reported data suggests that the phase imaging techniques are suited to be used as precise and non-destructive refractive index shift measuring tools to study and control the inscription process of optical waveguides.
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Janicek P, Slang S, Palka K, Vlcek M. Spectroscopic ellipsometry characterization of spin-coated Ge25S75 chalcogenide thin films. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2016-1019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractSpectroscopic ellipsometry study on spin-coated non-toxic Ge25S75 thin films annealed at different temperatures were conducted. Multi sample analysis with two sets of samples spin-coated onto soda-lime glass and onto silicon wafers was utilized. Optical constants (refractive index n and extinction coefficient k) of these films were determined from ellipsometric data recorded over a wide spectral range (0.05–6 eV). Different parametrization of Ge25S75 complex dielectric permittivity which consists of a Tauc-Lorentz or Cody-Lorentz oscillator describing the short wavelength absorption edge, a Lorentz or Gauss oscillators describing phonon absorption or optically active absorption of alkyl ammonium germanium salts in the middle infrared part of spectra is discussed. Using a Mott-Davis model, the decrease in local disorder with increasing annealing temperature is quantified from the short wavelength absorption edge onset. Using the Wemple-DiDomenico single oscillator model for the transparent part of the optical constants spectra, a decrease in the centroid distance of the valence and conduction bands with increasing annealing temperature is shown and increase in intensity of the inter-band optical transition due to annealing temperature occurs. Intensity of absorption near 3000 cm−1 could be used as alternative method to evaluation of quality of prepared films.
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Affiliation(s)
- Petr Janicek
- Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
- Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
| | - Stanislav Slang
- Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
| | - Karel Palka
- Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
| | - Miroslav Vlcek
- Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentska 95, Pardubice 53210, Czech Republic
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Chen H, Keiser C, Du S, Gao HJ, Sutter P, Sutter E. Termination of Ge surfaces with ultrathin GeS and GeS2 layers via solid-state sulfurization. Phys Chem Chem Phys 2017; 19:32473-32480. [DOI: 10.1039/c7cp05990f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Thermally activated solid-state reactions of germanium with sulfur give rise to passivating germanium sulfide surface layers.
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Affiliation(s)
- Hui Chen
- Department of Electrical & Computer Engineering
- University of Nebraska-Lincoln
- Lincoln
- USA
- Institute of Physics & University of Chinese Academy of Sciences
| | - Courtney Keiser
- Department of Mechanical & Materials Engineering
- University of Nebraska-Lincoln
- Lincoln
- USA
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Hong-Jun Gao
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Peter Sutter
- Department of Electrical & Computer Engineering
- University of Nebraska-Lincoln
- Lincoln
- USA
| | - Eli Sutter
- Department of Mechanical & Materials Engineering
- University of Nebraska-Lincoln
- Lincoln
- USA
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Lapointe J, Ledemi Y, Loranger S, Iezzi VL, Soares de Lima Filho E, Parent F, Morency S, Messaddeq Y, Kashyap R. Fabrication of ultrafast laser written low-loss waveguides in flexible As₂S₃ chalcogenide glass tape. OPTICS LETTERS 2016; 41:203-6. [PMID: 26766674 DOI: 10.1364/ol.41.000203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
As2S3 glass has a unique combination of optical properties, such as wide transparency in the infrared region and a high nonlinear coefficient. Recently, intense research has been conducted to improve photonic devices using thin materials. In this Letter, highly uniform rectangular single-index and 2 dB/m loss step-index optical tapes have been drawn by the crucible technique. Low-loss (<0.15 dB/cm) single-mode waveguides in chalcogenide glass tapes have been fabricated using femtosecond laser writing. Optical backscatter reflectometry has been used to study the origin of the optical losses. A detailed study of the laser writing process in thin glass is also presented to facilitate a repeatable waveguide inscription recipe.
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