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Ultrafast laser inscribed waveguides in tailored fluoride glasses: an enabling technology for mid-infrared integrated photonics devices. Sci Rep 2022; 12:14674. [PMID: 36038637 PMCID: PMC9424227 DOI: 10.1038/s41598-022-18701-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 08/17/2022] [Indexed: 11/08/2022] Open
Abstract
Zirconium fluoride (ZBLAN) glass, the standard material used in fiber-based mid-infrared photonics, has been re-designed to enable the fabrication of high index-contrast low-loss waveguides via femtosecond laser direct writing. We demonstrate that in contrast to pure ZBLAN, a positive index change of close to 10-2 can be induced in hybrid zirconium/hafnium (Z/HBLAN) glasses during ultrafast laser inscription and show that this can be explained by an electron cloud distortion effect that is driven by the existence of two glass formers with contrasting polarizability. High numerical aperture (NA) type-I waveguides that support a well confined 3.1 μm wavelength mode with a mode-field diameter (MFD) as small as 12 μm have successfully been fabricated. These findings open the door for the fabrication of mid-infrared integrated photonic devices that can readily be pigtailed to existing ZBLAN fibers.
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Shimizu M, Sato K, Nakashima K, Kiyosawa T, MATSUOKA J, Shimotsuma Y, Miura K. Composition-dependent sign inversion of the Soret coefficient of SiO 2 in binary borosilicate melts. J Chem Phys 2022; 156:214504. [DOI: 10.1063/5.0090939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using a laser-induced local-heating experiment combined with temperature analysis, we observed the composition-dependent sign inversion of the Soret coefficient of SiO2 in binary silicate melts, which was successfully explained by a modified Kempers model used for describing the Soret effect in oxide melts. In particular, the diffusion of SiO2 to the cold side under a temperature gradient, which is an anomaly in silicate melts, was observed in the SiO2-poor compositions. The theoretical model indicates that the thermodynamic mixing properties of oxides, partial molar enthalpy of mixing, and partial molar volume are the dominant factors for determining the migration direction of the SiO2 component under a temperature gradient.
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Affiliation(s)
- Masahiro Shimizu
- Kyoto University Graduate School of Engineering Department of Material Chemistry, Japan
| | | | | | | | | | | | - Kiyotaka Miura
- Kyoto University Graduate School of Engineering Department of Material Chemistry, Japan
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Macias-Montero M, Moreno-Zárate P, Muñoz F, Sotillo B, Garcia-Pardo M, Serna R, Fernandez P, Solis J. Competition Effects during Femtosecond Laser Induced Element Redistribution in Ba- and La-Migration Based Laser Written Waveguides. MATERIALS 2021; 14:ma14123185. [PMID: 34207797 PMCID: PMC8227110 DOI: 10.3390/ma14123185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 12/02/2022]
Abstract
Fs-laser induced element redistribution (FLIER) has been a subject of intensive research in recent years. Its application to various types of glasses has already resulted in the production of efficient optical waveguides, tappers, amplifiers and lasers. Most of the work reported on FLIER-based waveguides refers to structures produced by the cross-migration of alkali (Na, K) and lanthanides (mostly La). The latter elements act as refractive index carrying elements. Herein, we report the production of Ba-based, FLIER-waveguides in phosphate glass with an index contrast > 10−2. Phosphate glasses modified with the same amount of Na2O and K2O, and variable amounts of BaO and/or La2O3 were used to produce the FLIER-waveguides with Ba and or La acting as index carriers. Ba-only modified glasses show a waveguide writing threshold and light guiding performance comparable to that of La-based structures. However, mixed Ba-La glasses show a much higher element migration threshold, and much smaller compositionally modified regions. This behavior is consistent with a competition effect in the cross-migration of both elements (Ba and La) against the alkalis. Such an effect can be applied to inhibit undesired element redistribution effects in fs-laser processing applications in multicomponent glasses.
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Affiliation(s)
- Manuel Macias-Montero
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006 Madrid, Spain; (M.M.-M.); (R.S.)
| | - Pedro Moreno-Zárate
- Electronic Engineering Department, National Technological Institute of Mexico, Campus Acatlan de Osorio, Carretera Acatlan—San Juan Ixcaquistla k.m. 5.5, Acatlan de Osorio 74949, Mexico;
| | - Francisco Muñoz
- Institute of Ceramics and Glass (ICV, CSIC), Kelsen 5, 28049 Madrid, Spain;
| | - Belén Sotillo
- Department of Materials Physics, Faculty of Physics, Complutense University of Madrid, 28040 Madrid, Spain; (B.S.); (P.F.)
| | - Marina Garcia-Pardo
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006 Madrid, Spain; (M.M.-M.); (R.S.)
| | - Rosalía Serna
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006 Madrid, Spain; (M.M.-M.); (R.S.)
| | - Paloma Fernandez
- Department of Materials Physics, Faculty of Physics, Complutense University of Madrid, 28040 Madrid, Spain; (B.S.); (P.F.)
| | - Javier Solis
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006 Madrid, Spain; (M.M.-M.); (R.S.)
- Correspondence: ; Tel.: +34-(56)-16800
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Macias-Montero M, Muñoz F, Sotillo B, Del Hoyo J, Ariza R, Fernandez P, Siegel J, Solis J. Femtosecond laser induced thermophoretic writing of waveguides in silicate glass. Sci Rep 2021; 11:8390. [PMID: 33863947 PMCID: PMC8052338 DOI: 10.1038/s41598-021-87765-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/31/2021] [Indexed: 11/15/2022] Open
Abstract
Here in, the fs-laser induced thermophoretic writing of microstructures in ad-hoc compositionally designed silicate glasses and their application as infrared optical waveguides is reported. The glass modification mechanism mimics the elemental thermal diffusion occurring in basaltic liquids at the Earth's mantle, but in a much shorter time scale (108 times faster) and over a well-defined micrometric volume. The precise addition of BaO, Na2O and K2O to the silicate glass enables the creation of positive refractive index contrast upon fs-laser irradiation. The influence of the focal volume and the induced temperature gradient is thoroughly analyzed, leading to a variety of structures with refractive index contrasts as high as 2.5 × 10-2. Two independent methods, namely near field measurements and electronic polarizability analysis, confirm the magnitude of the refractive index on the modified regions. Additionally, the functionality of the microstructures as waveguides is further optimized by lowering their propagation losses, enabling their implementation in a wide range of photonic devices.
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Affiliation(s)
- Manuel Macias-Montero
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006, Madrid, Spain.
| | - Francisco Muñoz
- Institute of Ceramics and Glass (ICV, CSIC), Kelsen 5, 28049, Madrid, Spain
| | - Belén Sotillo
- Department of Materials Physics, Faculty of Physics, University Complutense of Madrid, 28040, Madrid, Spain
| | - Jesús Del Hoyo
- Department of Optics, Faculty of Physics, University Complutense of Madrid, 28040, Madrid, Spain
| | - Rocío Ariza
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006, Madrid, Spain
- Department of Materials Physics, Faculty of Physics, University Complutense of Madrid, 28040, Madrid, Spain
| | - Paloma Fernandez
- Department of Materials Physics, Faculty of Physics, University Complutense of Madrid, 28040, Madrid, Spain
| | - Jan Siegel
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006, Madrid, Spain
| | - Javier Solis
- Laser Processing Group, Institute of Optics (IO, CSIC), Serrano 121, 28006, Madrid, Spain.
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Shimizu M, Fukuyo T, Matsuoka J, Nakashima K, Sato K, Kiyosawa T, Nishi M, Shimotsuma Y, Miura K. Determination of thermodynamic and microscopic origins of the Soret effect in sodium silicate melts: Prediction of sign change of the Soret coefficient. J Chem Phys 2021; 154:074501. [PMID: 33607869 DOI: 10.1063/5.0040513] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Soret effect in silicate melts has attracted attention in earth and material sciences, particularly in glass science and engineering, because a compositional change caused by the Soret effect modifies the material properties of silicate melts. We investigated the Soret effect in an Na2O-SiO2 system, which is the most common representative of silicate melts. Our theoretical approach based on the modified Kempers model and non-equilibrium molecular dynamics simulation was validated for 30Na2O-70SiO2(mol. %). The sign and order of the absolute values of the calculated Soret coefficients were consistent with the experimental values. The positive Soret coefficient of SiO2 in the SiO2-poor composition range was accurately predicted. Previous experimental studies have focused on SiO2-rich compositions, and only the negative sign, indicating SiO2 migration to the hot side, has been observed. In the SiO2-poor composition range, the Q0 structure was dominant and had four Si-O-Na bonds around an SiO4 unit. The Si-O-Na bond had high enthalpic stability and contributed to the large negative enthalpy of SiO2 mixing. According to our model, components with a large negative partial molar enthalpy of mixing will concentrate in the cold region. The microscopic and thermodynamic origins of the sign change in the Soret effect were determined.
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Affiliation(s)
- Masahiro Shimizu
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tsubasa Fukuyo
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Jun Matsuoka
- School of Engineering, The University of Shiga Prefecture, Hikone 522-8533, Japan
| | - Kento Nakashima
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kenzo Sato
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tomohiro Kiyosawa
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Masayuki Nishi
- Department of Mechanical and Electrical System Engineering, Faculty of Engineering, Kyoto University of Advanced Science, Ukyo-ku, Kyoto 615-8577, Japan
| | - Yasuhiko Shimotsuma
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kiyotaka Miura
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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Record-high positive refractive index change in bismuth germanate crystals through ultrafast laser enhanced polarizability. Sci Rep 2020; 10:15142. [PMID: 32934325 PMCID: PMC7492192 DOI: 10.1038/s41598-020-72234-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/06/2020] [Indexed: 11/08/2022] Open
Abstract
Unlike other crystals, the counter intuitive response of bismuth germanate crystals ([Formula: see text], BGO) to form localized high refractive index contrast waveguides upon ultrafast laser irradiation is explained for the first time. While the waveguide formation is a result of a stoichiometric reorganization of germanium and oxygen, the origin of positive index stems from the formation of highly polarisable non-bridging oxygen complexes. Micro-reflectivity measurements revealed a record-high positive refractive index contrast of [Formula: see text]. The currently accepted view that index changes [Formula: see text] could be brought about only by engaging heavy metal elements is strongly challenged by this report. The combination of a nearly perfect step-index profile, record-high refractive index contrast, easily tunable waveguide dimensions, and the intrinsic high optical non-linearity, electro-optic activity and optical transparency up to [Formula: see text] of BGO make these waveguides a highly attractive platform for compact 3D integrated optics.
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Spagnolo M, Motta R, Memeo R, Pellegatta F, Crespi A, Osellame R. Resonant opto-mechanical modulators and switches by femtosecond laser micromachining. OPTICS EXPRESS 2020; 28:23133-23142. [PMID: 32752314 DOI: 10.1364/oe.396513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/16/2020] [Indexed: 05/23/2023]
Abstract
In this work we demonstrate novel integrated-optics modulators and switches, realized in a glass substrate by femtosecond laser pulses. These devices are based on oscillating microcantilevers, machined by water-assisted laser ablation. Single-mode optical waveguides are laser-inscribed inside the cantilever beam and continue in the substrate beyond the cantilever's tip. By exciting the resonant oscillation of the mechanical structure, coupling between the waveguide segments is varied in time. Operation frequencies are in the range of tens of kilohertz, thus they markedly overcome the response-time limitation of other glass-based modulators, which rely on the thermo-optic effect. These components may be integrated in more complex waveguide circuits or optofluidic lab-on-chips, to provide periodic and high-frequency modulation of the optical signals.
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