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Smart mid-infrared metasurface microspectrometer gas sensing system

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MICROsystems & NANOENGINEERING 2024年第1期10卷 1-9页

作者： Meng, Jiajun Balendhran, Sivacarendran Sabri, Ylias Bhargava, Suresh K. Crozier, Kenneth B. Univ Melbourne Sch Phys Parkville Vic Australia Univ Melbourne Ctr Excellence Transformat Meta Opt Syst TMOS Australian Res Council ARC Parkville Vic Australia Univ Melbourne Dept Elect & Elect Engn Melbourne Vic Australia RMIT Univ Ctr Adv Mat & Ind Chem CAMIC STEM Coll Melbourne Vic Australia

Smart, low-cost and portable gas sensors are highly desired due to the importance of air quality monitoring for environmental and defense-related applications. Traditionally, electrochemical and nondispersive infrared (IR) gas sensors are designed to detect a single specific analyte. Although IR spectroscopy-based sensors provide superior performance, their deployment is limited due to their large size and high cost. In this study, a smart, low-cost, multigas sensing system is demonstrated consisting of a mid-infrared microspectrometer and a machine learning algorithm. The microspectrometer is a metasurface filter array integrated with a commercial IR camera that is consumable-free, compact (similar to 1 cm(3)) and lightweight (similar to 1 g). The machine learning algorithm is trained to analyze the data from the microspectrometer and predict the gases present. The system detects the greenhouse gases carbon dioxide and methane at concentrations ranging from 10 to 100% with 100% accuracy. It also detects hazardous gases at low concentrations with an accuracy of 98.4%. Ammonia can be detected at a concentration of 100 ppm. Additionally, methyl-ethyl-ketone can be detected at its permissible exposure limit (200 ppm); this concentration is considered low and nonhazardous. This study demonstrates the viability of using machine learning with IR spectroscopy to provide a smart and low-cost multigas sensing platform.

关键词： Micro-optics optical sensors

Harnessing the power of complex light propagation in multimode fibers for spatially resolved sensing

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Photonics research 2024年第3期12卷 411-422页

作者： DARCY L.SMITH LINH V.NGUYEN MOHAMMAD I.REJA ERIK P.SCHARTNER HEIKE EBENDORFF-HEIDEPRIEM DAVID J.OTTAWAY STEPHEN C.WARREN-SMITH Institute for Photonics and Advanced Sensing and School of Physics Chemistry and Earth SciencesThe University of AdelaideAdelaideSA 5005Australia australian research council centre of excellence for Gravitational Wave Discovery(OzGrav) AdelaideSAAustralia Future Industries Institute University of South AustraliaMawson LakesSA 5095Australia Laser Physics and Photonics Devices Laboratory University of South AustraliaMawson LakesSA 5095Australia

The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental *** properties can be a powerful tool for sensing,as small perturbations lead to significant changes in the output of the ***,the mechanism to encode spatially resolved sensing information into the speckle pattern and the ability to extract this information are thus far *** this paper,we demonstrate that spatially dependent mode coupling is crucial to achieving spatially resolved *** leverage machine learning to quantitatively extract the spatially resolved sensing information from three fiber types with dramatically different characteristics and demonstrate that the fiber with the highest degree of spatially dependent mode coupling provides the greatest accuracy.

关键词： fiber spatially resolved

Photon pair generation from lithium niobate metasurface with tunable spatial entanglement[Invited]

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Chinese Optics Letters 2023年第1期21卷 25-31页

作者：张吉化马进勇 Dragomir N.Neshev Andrey A.Sukhorukov centre of excellence for transformative meta-optical systems(TMOS) Department of Electronic Materials Engineering(EME)Research School of PhysicsThe Australian National UniversityCanberraACT 2601Australia

The two-photon state with spatial entanglement is an essential resource for testing fundamental laws of quantum mechanics and various quantum *** creation typically relies on spontaneous parametric downconversion in bulky nonlinear crystals where the tunability of spatial entanglement is ***,we predict that ultrathin nonlinear lithium niobate metasurfaces can generate and diversely tune spatially entangled photon *** spatial properties of photons including the emission pattern,rate,and degree of spatial entanglement are analyzed theoretically with the coupled mode theory and Schmidt decomposition *** show that by leveraging the strong angular dispersion of the metasurface,the degree of spatial entanglement quantified by the Schmidt number can be decreased or increased by changing the pump laser wavelength and a Gaussian beam *** flexibility can facilitate diverse quantum applications of entangled photon states generated from nonlinear metasurfaces.

关键词： spontaneous parametric downconversion metasurface spatial entanglement

Nonpolar Al_(x)Ga_(1−x)N/Al_(y)Ga_(1−y)N multiple quantum wells on GaN nanowire for UV emission

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Nano research 2022年第8期15卷 7670-7680页

作者： Sonachand Adhikari Olivier Lee Cheong Lem Felipe Kremer Kaushal Vora Frank Brink Mykhaylo Lysevych Hark Hoe Tan Chennupati Jagadish Department of Electronic Materials Engineering Research School of PhysicsThe Australian National UniversityCanberraAustralian Capital Territory 2601Australia Semiconductor Device Fabrication Group CSIR-Central Electronics Engineering Research InstitutePilaniRajasthan 333031India australian National Fabrication Facility ACT Node Research School of PhysicsThe Australian National UniversityCanberraAustralian Capital Territory 2601Australia centre for Advanced Microscopy The Australian National UniversityCanberraAustralian Capital Territory 2601Australia australian research council centre of excellence for transformative meta-optical systems Research School of PhysicsThe Australian National UniversityCanberraAustralian Capital Territory 2601Australia

Nonpolar m-plane AlGaN offers the advantage of polarization-free multiple quantum wells(MQWs)for ultraviolet(UV)emission and can be achieved on the sidewalls of selective area grown GaN *** reveal that the growth of AlGaN on GaN nanowires by metal organic chemical vapor deposition(MOCVD)is driven by vapor-phase diffusion,and consequently puts a limit on the pitch of nanowire array due to shadowing *** insight into the difficulty of achieving metal-polar AlGaN nanowire by selective area growth(SAG)in MOCVD is also provided and can be attributed to the strong tendency to form pyramidal structure due to a very small growth rate of{1011}semipolar planes compared to(0001)*** nonpolar m-plane sidewalls of GaN nanowires obtained via SAG provides an excellent platform for growth of nonpolar AlGaN *** emission from mplane Al_(x)Ga_(1−x)N/Al_(y)Ga_(1−y)N MQWs grown on sidewalls of dislocation-free GaN nanowire is demonstrated in the wavelength range of 318–343 nm.

关键词： metal organic chemical vapor deposition(MOCVD) nanowire nonpolar plane AlGaN selective area growth multiple quantum wells

Tuning the crystal structure and optical properties of selective area grown InGaAs nanowires

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Nano research 2022年第4期15卷 3695-3703页

作者： Zahra Azimi Aswani Gopakumar Amira SAmeruddin Li Li Thien Truong Hieu TNguyen Hark Hoe Tan Chennupati Jagadish Jennifer Wong-Leung Department of Electronic Materials Engineering Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia Faculty of Applied Science and Technology Universiti Tun Hussein Onn MalaysiaBatu Pahat 86400Malaysia australian National Fabrication Facility ACT Node Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia School of Engineering The Australian National UniversityCanberra ACT 2601Australia australian research council centre of excellence for transformative meta-optical systems Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia

Catalyst-free InGaAs nanowires grown by selective area epitaxy are promising building blocks for future optoelectronic devices in the infrared spectral *** progress,the role of pattern geometry and growth parameters on the composition,microstructure,and optical properties of InGaAs nanowires is still ***,we present an optimised growth parameter window to achieve highly uniform In1-xGaxAs nanowire arrays on GaAs(111)B substrate over an extensive range of Ga concentrations,from 0.1 to 0.91,by selective-area metal-organic vapor-phase *** observe that the Ga content always increases with decreasing In/(Ga+In)precursor ratio and group V flow rate and increasing growth *** increase in Ga content is supported by a blue shift in the photoluminescence peak *** geometry of the nanowire arrays also plays an important role in the resulting ***,increasing the nanowire pitch size from 0.6 to 2μm in a patterned array shifts the photoluminescence peak emission by up to 120 *** of these growth and geometry parameters,the Ga content determines the crystal structure,resulting in a predominantly wurtzite structure for xGa≤0.3 and a predominantly zinc blende phase for xGa≥*** insights on the factors controlling the composition of InGaAs nanowires grown by a scalable catalyst-free approach provide directions for engineering nanowires as functional components of future optoelectronic devices.

关键词： InGaAs nanowires ternary semiconductors selective-area metal-organic vapor-phase epitaxy nanostructure pattern geometry

Nonlinear quantum spectroscopy with parity-time-symmetric integrated circuits

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Photonics research 2022年第7期10卷 1763-1776页

作者： PAWAN KUMAR SINA SARAVI THOMAS PERTSCH FRANK SETZPFANDT ANDREY A.SUKHORUKOV Institute of Applied Physics Abbe Center of PhotonicsFriedrich Schiller University Jena07745 JenaGermany Fraunhofer Institute for Applied Optics and Precision Engineering 07745 JenaGermany research School of Physics Australian National UniversityCanberraACT 2601Australia ARC centre of excellence for transformative meta-optical systems(TMOS) Australia

We propose a novel quantum nonlinear interferometer design that incorporates a passive parity-time(PT)-symmetric coupler sandwiched between two nonlinear sections where signal-idler photon pairs are *** PT symmetry enables efficient coupling of the longer-wavelength idler photons and facilitates the sensing of losses in the second waveguide exposed to analyte under investigation,whose absorption can be inferred by measuring only the signal intensity at a shorter wavelength where efficient detectors are readily ***,we identify a new phenomenon of sharp signal intensity fringe shift at critical idler loss values,which is distinct from the previously studied PT symmetry *** discuss how such unconventional properties arising from quantum interference can provide a route to enhancing the sensing of analytes and facilitate broadband spectroscopy applications in integrated photonic platforms.

关键词： interferometer waveguide quantum

Fundamental limits for transmission modulation in VO_(2) metasurfaces

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Photonics research 2023年第1期11卷 I0002-I0011页

作者： BOHAN LI ROCIO CAMACHO-MORALES NEUTON LI ANDREA TOGNAZZI MARCO GANDOLFI DOMENICO DE CEGLIA COSTANTINO DE ANGELIS ANDREY A.SUKHORUKOV ANDDRAGOMIR N.NESHEV ARC centre of excellence for transformative meta-optical systems(TMOS) Department of Electronic Materials EngineeringResearch School of PhysicsThe Australian National UniversityCanberraACT 2601Australia Department of Engineering University of PalermoPalermo 90128Italy Istituto Nazionale di Ottica Consiglio Nazionale delle RicercheBrescia 25123Italy Department of Information Engineering University of BresciaBrescia 25123Italy

The interest in dynamic modulation of light by ultra-thin materials exhibiting insulator–metal phase transition,such as VO_(2),has rapidly grown due to the myriad industrial applications,including smart windows and optical ***,for applications in the telecommunication spectral band,the light modulation through a thin VO_(2) film is low due to the presence of strong material ***,we demonstrate tailored nanostructuring of VO_(2) to dramatically enhance its transmission modulation,reaching a value as high as 0.73,which is 2 times larger than the previous modulation *** resulting designs,including free-topology optimization,demonstrate the fundamental limit in acquiring the desired optical performance,including achieving positive or negative transmission *** results on nanophotonic management of lossy nanostructured films open new opportunities for applications of VO_(2) metasurfaces.

关键词： surfaces desired smart

Light field on a chip: metasurface-based multicolor holograms

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Advanced Photonics 2021年第2期3卷 1-14页

作者： Dandan Wen Jasper J.Cadusch Jiajun Meng Kenneth B.Crozier University of Melbourne Department of Electrical and Electronic EngineeringVictoriaAustralia University of Melbourne School of PhysicsVictoriaAustralia University of Melbourne Australian Research CouncilCentre of Excellence for Transformative Meta-Optical SystemsVictoriaAustralia

Multicolor holography can faithfully record the color,depth,parallax,and other properties of scenes and have thus found numerous applications,for example,in optical document security,nonvolatile data storage,and virtual or augmented reality *** metasurfaces present multiple degrees of freedom to manipulate the properties of optical fields at visible *** in turn provide opportunities for metasurface-based multicolor *** describe recent developments in multicolor metasurface *** are categorized based on their color-separating mechanisms rather than their structural properties,such as whether they are plasmonic or *** hope this review will provide readers with new insights and thus help extend applications of metasurface-based multicolor holography to other fields.

关键词： multicolor hologram metasurface

Influence of preterm birth on the association between gestational diabetes mellitus and childhood developmental vulnerability:a causal mediation analysis

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World Journal of Pediatrics 2024年第1期20卷 54-63页

作者： Bereket Duko Amanuel Tesfay Gebremedhin Gizachew Assefa Tessema Gavin Pereira australian centre for Precision Health UniSA Clinical and Health SciencesUniversity of South AustraliaNorth TerraceAdelaideSA5000Australia Curtin School of Population Health Faculty of Health SciencesCurtin UniversityKent StreetBentleyWA 6102Australia enAble Institute Curtin UniversityKent StreetBentleyWA6102Australia centre for Fertility and Health(CeFH) Norwegian Institute of Public HealthOsloNorway

Background Epidemiological studies examining the direct and indirect effects of gestational diabetes mellitus(GDM)on offspring early childhood developmental vulnerability are ***,the aims of this study were to estimate the direct and indirect effects of GDM(through preterm birth)on early childhood developmental *** We conducted a retrospective population-based cohort study on the association between gestational diabetes mellitus and early childhood developmental vulnerability in children born in Western Australia(WA)using maternal,infant and birth records from the Midwives Notification,Hospitalizations,Developmental Anomalies,and the australian Early Development Census(AEDC)*** used two aggregated outcome measures:developmentally vulnerable on at least one AEDC domain(DV1)and developmentally vulnerable on at least two AEDC domains(DV2).Causal mediation analysis was applied to estimate the natural direct(NDE),indirect(NIE),and total(TE)effects as relative risks(RR).Results In the whole cohort(n=64,356),approximately 22%were classified as DV1 and 11%as DV2 on AEDC *** of the natural direct effect suggested that children exposed to GDM were more likely to be classified as DV1(RR=1.20,95%CI:1.10-1.31)and DV2(RR=1.34,95%CI:1.19-1.50)after adjusting for potential *** 6%and 4%of the effect of GDM on early childhood developmental vulnerability was mediated by preterm birth for DV1 and DV2,*** Children exposed to gestational diabetes mellitus were more likely to be developmentally vulnerable in one or more AEDC *** biological mechanism for these associations is not well explained by mediation through preterm birth.

关键词： Child development Causal mediation analysis Gestational diabetes mellitus Offspring