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Yang Z, Yan K, Wei T, Sun Y, Xu P, Madden S, Wang R. Real-time change of optical losses in chalcogenide waveguides induced by light illumination. OPTICS LETTERS 2022; 47:5565-5568. [PMID: 37219269 DOI: 10.1364/ol.473962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 05/24/2023]
Abstract
We prepared several GeGaSe waveguides with different chemical compositions and measured the change of optical losses induced by light illumination. Together with some experimental data in As2S3 and GeAsSe waveguides, the results showed that maximum change of the optical loss can be observed in the waveguides under bandgap light illumination. The chalcogenide waveguides with close to stoichiometric compositions have less homopolar bonds and less sub-bandgap states, and thus are preferential to have less photoinduced losses.
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Gao J, Vincenti MA, Frantz J, Clabeau A, Qiao X, Feng L, Scalora M, Litchinitser NM. Near-infrared to ultra-violet frequency conversion in chalcogenide metasurfaces. Nat Commun 2021; 12:5833. [PMID: 34611169 PMCID: PMC8492647 DOI: 10.1038/s41467-021-26094-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/10/2021] [Indexed: 11/09/2022] Open
Abstract
Chalcogenide photonics offers unique solutions for a broad range of applications from mid-infrared sensing to integrated, ultrafast, ultrahigh-bandwidth signal processing. However, to date its usage has been limited to the infrared part of the electromagnetic spectrum, thus avoiding ultraviolet and visible ranges due to absorption of chalcogenide glasses. Here, we experimentally demonstrate and report near-infrared to ultraviolet frequency conversion in an As2S3-based metasurface, enabled by a phase locking mechanism between the pump and the inhomogeneous portion of the third harmonic signal. Due to the phase locking, the inhomogeneous component co-propagates with the pump pulse and encounters the same effective dispersion as the infrared pump, and thus experiences little or no absorption, consequently opening previously unexploited spectral range for chalcogenide glass science and applications, despite the presence of strong material absorption in this range. The use of chalcogenide glass in optical science and applications at the UV frequencies has been so far hindered by its absorption in this spectral region. Here the authors demonstrate that a nanostructured chalcogenide glass can efficiently generate third harmonic radiation, leading to a strong UV light source at the nanoscale.
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Affiliation(s)
- Jiannan Gao
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA
| | | | - Jesse Frantz
- US Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC, 20375, USA
| | - Anthony Clabeau
- University Research Foundation, 6411 Ivy Ln. 110, Greenbelt, MD, 20770, USA
| | - Xingdu Qiao
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Liang Feng
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael Scalora
- Aviation and Missile Center, US Army CCDC, Redstone Arsenal, AL, 35898-5000, USA
| | - Natalia M Litchinitser
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA.
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Experimental design approach for deposition optimization of RF sputtered chalcogenide thin films devoted to environmental optical sensors. Sci Rep 2017; 7:3500. [PMID: 28615650 PMCID: PMC5471270 DOI: 10.1038/s41598-017-03678-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 05/03/2017] [Indexed: 11/08/2022] Open
Abstract
The development of the optical bio-chemical sensing technology is an extremely important scientific and technological issue for diagnosis and monitoring of diseases, control of industrial processes, environmental detection of air and water pollutants. Owing to their distinctive features, chalcogenide amorphous thin films represent a keystone in the manufacture of middle infrared integrated optical devices for a sensitive detection of biological or environmental variations. Since the chalcogenide thin films characteristics, i.e. stoichiometric conformity, structure, roughness or optical properties can be affected by the growth process, the choice and control of the deposition method is crucial. An approach based on the experimental design is undoubtedly a way to be explored allowing fast optimization of chalcogenide film deposition by means of radio frequency sputtering process. Argon (Ar) pressure, working power and deposition time were selected as potentially the most influential factors among all possible. The experimental design analysis confirms the great influence of the Ar pressure on studied responses: chemical composition, refractive index in near-IR (1.55 µm) and middle infrared (6.3 and 7.7 µm), band-gap energy, deposition rate and surface roughness. Depending on the intended application and therefore desired thin film characteristics, mappings of the experimental design meaningfully help to select suitable deposition parameters.
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Hawlová P, Bouška M, Nazabal V, Baudet E, Černošek Z, Němec P. Photostability of pulsed-laser-deposited As xTe 100-x (x=40, 50, 60) amorphous thin films. OPTICS LETTERS 2017; 42:1660-1663. [PMID: 28454129 DOI: 10.1364/ol.42.001660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
AsxTe100-x amorphous thin films were fabricated by a pulsed laser deposition technique with the aim of finding photostable layers in as-deposited but preferably in relaxed (annealed) state. Photostability was studied in terms of the films' stability of refractive index and bandgap under near-bandgap light irradiation. As40Te60 and As50Te50 layers were found to be photostable in both as-deposited as well as relaxed states. Moreover, As50Te50 layers present the lowest surface roughness. These characteristics make pulsed-laser-deposited As50Te50 thin films promising for applications in nonlinear optics.
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Bouška M, Pechev S, Simon Q, Boidin R, Nazabal V, Gutwirth J, Baudet E, Němec P. Pulsed laser deposited GeTe-rich GeTe-Sb2Te3 thin films. Sci Rep 2016; 6:26552. [PMID: 27199107 PMCID: PMC4873812 DOI: 10.1038/srep26552] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/03/2016] [Indexed: 12/02/2022] Open
Abstract
Pulsed laser deposition technique was used for the fabrication of Ge-Te rich GeTe-Sb2Te3 (Ge6Sb2Te9, Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15) amorphous thin films. To evaluate the influence of GeTe content in the deposited films on physico-chemical properties of the GST materials, scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction and reflectometry, atomic force microscopy, Raman scattering spectroscopy, optical reflectivity, and sheet resistance temperature dependences as well as variable angle spectroscopic ellipsometry measurements were used to characterize as-deposited (amorphous) and annealed (crystalline) layers. Upon crystallization, optical functions and electrical resistance of the films change drastically, leading to large optical and electrical contrast between amorphous and crystalline phases. Large changes of optical/electrical properties are accompanied by the variations of thickness, density, and roughness of the films due to crystallization. Reflectivity contrast as high as ~0.21 at 405 nm was calculated for Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15 layers.
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Affiliation(s)
- M. Bouška
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - S. Pechev
- Institut de Chimie de la Matière Condensée de Bordeaux – CNRS, 87, av. du Dr. Albert Schweitzer, 33608 Pessac Cedex, France
| | - Q. Simon
- Institut de Chimie de la Matière Condensée de Bordeaux – CNRS, 87, av. du Dr. Albert Schweitzer, 33608 Pessac Cedex, France
| | - R. Boidin
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - V. Nazabal
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
- Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex, France
| | - J. Gutwirth
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - E. Baudet
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - P. Němec
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
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de Araújo CB, Gomes ASL, Boudebs G. Techniques for nonlinear optical characterization of materials: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:036401. [PMID: 26863100 DOI: 10.1088/0034-4885/79/3/036401] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Various techniques to characterize the nonlinear (NL) optical response of centro-symmetric materials are presented and evaluated with emphasis on the relationship between the macroscopic measurable quantities and the microscopic properties of photonic materials. NL refraction and NL absorption of the materials are the phenomena of major interest. The dependence of the NL refraction and NL absorption coefficients on the nature of the materials was studied as well as on the laser excitation characteristics of wavelength, intensity, spatial profile, pulse duration and pulses repetition rate. Selected experimental results are discussed and illustrated. The various techniques currently available were compared and their relative advantages and drawbacks were evaluated. Critical comparisons among established techniques provided elements to evaluate their accuracies and sensitivities with respect to novel methods that present improvements with respect to the conventional techniques.
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Affiliation(s)
- Cid B de Araújo
- Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE, Brazil
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Khan P, Yadav RK, Bhattacharya A, Joshy A, Aneesh J, Adarsh KV. Tuning nanosecond transient absorption in a-Ge₂₅As₁₀Se₆₅ thin films via background illumination. OPTICS LETTERS 2015; 40:4512-4515. [PMID: 26421569 DOI: 10.1364/ol.40.004512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this Letter, we report for the first time, to the best of our knowledge, continuous-wave laser background illumination (BGI) as a simple and yet useful tool to tune nanosecond transient absorption (TA) in a-Ge25As10Se65 thin films. In our experiments, we observed remarkable blueshift in TA as a function of the BGI intensity. Strikingly, relaxations of TA in background-illuminated samples are much faster than the as-prepared samples. This observation provides new insights into the bond-breaking mechanism. Further, decay time constants of TA are wavelength dependent, which signifies that excited carriers have a longer lifetime in deep traps than in shallow traps.
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Khan P, Sharma R, Deshpande U, Adarsh KV. First observation of the temperature-dependent light-induced response of Ge(25)As(10)Se(65) thin films. OPTICS LETTERS 2015; 40:1559-1562. [PMID: 25831384 DOI: 10.1364/ol.40.001559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ge-rich ternary chalcogenide glasses (ChGs) exhibit photobleaching (PB) when illuminated with bandgap light. This effect originates from the combined effects of intrinsic structural changes and photo-oxidation. In a sharp contradiction to previous observations, in this Letter, we demonstrate, for the first time, that Ge-rich Ge(25)As(10)Se(65) ChG thin films exhibit photodarkening (PD) at 20 K and PB at 300 and 420 K after having been continuously illuminated for ∼3 hours. The temporal evolution of PD/PB shows distinct characteristics at the temperature of illumination, and provides valuable information on the light-induced structural changes. Furthermore, structure-specific far-infrared (FIR) absorption measurements give direct evidence of different structural units involved in PD/PB at the contrasting temperatures. By comparing the light-induced effects in vacuum and air, we conclude that intrinsic structural changes dominate over photo-oxidation in the observed PB in Ge(25)As(10)Se(65) ChG thin films.
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Hawlová P, Verger F, Nazabal V, Boidin R, Němec P. Test-photostability of pulsed laser deposited amorphous thin films from Ge-As-Te system. Sci Rep 2015; 5:9310. [PMID: 25797340 PMCID: PMC4369751 DOI: 10.1038/srep09310] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/16/2014] [Indexed: 11/11/2022] Open
Abstract
Amorphous thin films from Ge-As-Te system were prepared by pulsed laser deposition to study their intrinsic photostability, morphology, chemical composition, structure and optical properties. Photostability of fabricated layers was studied by spectroscopic ellipsometry within as-deposited as well as relaxed (annealed) layers. For irradiation, laser sources operating at three wavelengths in band gap region of the studied materials were employed. The results show that lowest values of photorefraction accompanied with lowest changes of band gap values were exhibited by Ge20As20Te60 thin films, which are therefore considered as the layers with highest photostability in relaxed state. The structure of the films is discussed based on Raman scattering spectroscopy data.
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Affiliation(s)
- P Hawlová
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic
| | - F Verger
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic
| | - V Nazabal
- 1] Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic [2] Institut des sciences chimiques de Rennes, UMR CNRS 6226, Equipe Verres et Céramiques, Université de Rennes 1, 35042 Rennes, France
| | - R Boidin
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic
| | - P Němec
- Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic
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Khan P, Saxena T, Adarsh KV. Tailoring between network rigidity and nanosecond transient absorption in a-Ge(x)As(35-x)Se₆₅ thin films. OPTICS LETTERS 2015; 40:768-771. [PMID: 25723428 DOI: 10.1364/ol.40.000768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Letter, we report the first observation of dramatic decrease in nanosecond (ns) pulsed laser-induced transient absorption (TA) in a-Ge(x)As(35-x)Se₆₅ thin films by tuning the amorphous network from floppy to rigid. Our results provide the direct experimental evidence of a self-trapped exciton mechanism, where trapping of the excitons occurs through bond rearrangements. Taken together, a rigid amorphous network with more constraints than degrees of freedom are unable to undergo any such bond rearrangements and results in weaker TA. However, we also demonstrate that excitation fluence can be effectively utilized as a simple tool to lift up enough constraints to introduce large TA even in rigid networks. Apart from this, we also show that TA is tunable with network rigidity as it blueshifts when the mean coordination is increased from 2.35 to 2.6.
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Khan P, Jain H, Adarsh KV. Role of Ge:As ratio in controlling the light-induced response of a-Ge(x)As(35-x)Se65 thin films. Sci Rep 2014; 4:4029. [PMID: 24504158 PMCID: PMC3916963 DOI: 10.1038/srep04029] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/22/2014] [Indexed: 11/15/2022] Open
Abstract
In this paper, we present interesting results on the quantification of photodarkening (PD), photobleaching (PB) and transient PD (TPD) in a-GexAs35−xSe65 thin films as a function of network rigidity. Composition dependent light-induced responses of these samples indicate that there exist two parallel competing mechanisms of instantaneous PD arising from the As part of the network, and PB arising from the Ge part of the network. Raman spectra of the as-prepared and illuminated samples provide first direct evidence of the light-induced structural changes: an increase in AsSe3/2 pyramidal and GeSe4/2 corner-sharing tetrahedra units together with new Ge-O bond formation and decrease in energetically unstable edge sharing GeSe4/2 tetrahedra. Importantly, for a fixed Se concentration, Ge:As ratio plays the critical role in controlling the net light-induced response rather than the much believed rigidity of the glassy network.
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Affiliation(s)
- Pritam Khan
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462023, India
| | - H Jain
- Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA
| | - K V Adarsh
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462023, India
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Barik AR, Adarsh KV, Naik R, Ganesan R, Yang G, Zhao D, Jain H, Shimakawa K. Role of rigidity and temperature in the kinetics of photodarkening in Ge(x)As(45-x)Se55 thin films. OPTICS EXPRESS 2011; 19:13158-13163. [PMID: 21747469 DOI: 10.1364/oe.19.013158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present insightful results on the kinetics of photodarkening (PD) in Ge(x)As(45-x)Se55 glasses at the ambient and liquid helium temperatures when the network rigidity is increased by varying x from 0 to 16. We observe a many fold change in PD and its kinetics with decreasing network flexibility and temperature. Moreover, temporal evolution of PD shows a dramatic change with increasing x.
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Affiliation(s)
- A R Barik
- Department of Physics, Indian Institute of Science Education and Research, Bhopal, India
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D'Aguanno G, de Ceglia D, Mattiucci N, Bloemer MJ. All-optical switching at the Fano resonances in subwavelength gratings with very narrow slits. OPTICS LETTERS 2011; 36:1984-1986. [PMID: 21633423 DOI: 10.1364/ol.36.001984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We theoretically discuss all-optical switching at the Fano resonances of subwavelength gratings made of a chalcogenide glass (As(2)S(3)). Particular attention is devoted to the case in which the grating possesses extremely narrow slits (channels ranging from a∼10 nm to a∼40 nm). The remarkable local field enhancement available in these situations conspires to yield low-threshold switching intensities (~50 MW/cm(2)) at telecommunication wavelengths for extremely thin (d∼200 nm) gratings when a realistic value of the As(2)S(3) cubic nonlinearity is used.
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Affiliation(s)
- G D'Aguanno
- Nanogenesis Division, AEgis Technologies, 410 Jan Davis Drive, Huntsville, Alabama 35806, USA.
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