ORCID Profile
0000-0002-4297-5274
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Photonics and Electro-Optical Engineering (excl. Communications) | Classical Physics | Photonics, Optoelectronics and Optical Communications | Nanophotonics | Classical and Physical Optics | Optical Physics | Nanotechnology | Photodetectors, Optical Sensors and Solar Cells | Electrostatics and Electrodynamics | Acoustics and Acoustical Devices; Waves
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Emerging Defence Technologies | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Reconfigurable Hyperbolic Polaritonics with Correlated Oxide Metasurfaces
Publisher: Research Square Platform LLC
Date: 19-10-2021
DOI: 10.21203/RS.3.RS-947391/V1
Abstract: Polaritons enable subwavelength confinement and highly anisotropic flows of light over a wide spectral range, holding the promise for applications in modern nanophotonic and optoelectronic devices. However, to fully realize their practical application potential, facile methods enabling nanoscale active control of polaritons are needed. Here, we introduce a hybrid polaritonic-oxide heterostructure platform consisting of van der Waals crystals, such as hexagonal boron nitride (hBN) or alpha-phase molybdenum trioxide (α-MoO 3 ), transferred on nanoscale oxygen vacancy patterns on the surface of prototypical correlated perovskite oxide SmNiO 3 (SNO). Using a combination of scanning probe microscopy and infrared nanoimaging techniques, we demonstrate nanoscale real-time reconfigurability of complex hyperbolic phonon polaritons patterned at the nanoscale with unmatched resolution. Hydrogenation and temperature modulation allow spatially localized conductivity modulation of SNO nanoscale patterns, enabling robust real-time modulation and nanoscale reconfiguration of hyperbolic polaritons. Our work paves the way towards nanoscale programmable metasurface engineering as a new paradigm for reconfigurable nanophotonic applications facilitated by a hybrid material platform exploiting extreme light-matter interactions in polaritonic systems.
Reconfigurable hyperbolic polaritonics with correlated oxide metasurfaces
Publisher: Springer Science and Business Media LLC
Date: 03-08-2022
DOI: 10.1038/S41467-022-32287-Z
Abstract: Polaritons enable subwavelength confinement and highly anisotropic flows of light over a wide spectral range, holding the promise for applications in modern nanophotonic and optoelectronic devices. However, to fully realize their practical application potential, facile methods enabling nanoscale active control of polaritons are needed. Here, we introduce a hybrid polaritonic-oxide heterostructure platform consisting of van der Waals crystals, such as hexagonal boron nitride (hBN) or alpha-phase molybdenum trioxide (α-MoO 3 ), transferred on nanoscale oxygen vacancy patterns on the surface of prototypical correlated perovskite oxide, samarium nickel oxide, SmNiO 3 (SNO). Using a combination of scanning probe microscopy and infrared nanoimaging techniques, we demonstrate nanoscale reconfigurability of complex hyperbolic phonon polaritons patterned at the nanoscale with high resolution. Hydrogenation and temperature modulation allow spatially localized conductivity modulation of SNO nanoscale patterns, enabling robust real-time modulation and nanoscale reconfiguration of hyperbolic polaritons. Our work paves the way towards nanoscale programmable metasurface engineering for reconfigurable nanophotonic applications.
Experimental observation of topological Z2 exciton-polaritons in transition metal dichalcogenide monolayers
Publisher: Springer Science and Business Media LLC
Date: 20-07-2021
DOI: 10.1038/S41467-021-24728-Y
Abstract: The rise of quantum science and technologies motivates photonics research to seek new platforms with strong light-matter interactions to facilitate quantum behaviors at moderate light intensities. Topological polaritons (TPs) offer an ideal platform in this context, with unique properties stemming from resilient topological states of light strongly coupled with matter. Here we explore polaritonic metasurfaces based on 2D transition metal dichalcogenides (TMDs) as a promising platform for topological polaritonics. We show that the strong coupling between topological photonic modes of the metasurface and excitons in TMDs yields a topological polaritonic Z 2 phase. We experimentally confirm the emergence of one-way spin-polarized edge TPs in metasurfaces integrating MoSe 2 and WSe 2 . Combined with the valley polarization in TMD monolayers, the proposed system enables an approach to engage the photonic angular momentum and valley and spin of excitons, offering a promising platform for photonic/solid-state interfaces for valleytronics and spintronics.
Finite-difference time-domain analysis of the tunneling and growing exponential in a pair ofε
Publisher: American Physical Society (APS)
Date: 18-07-2006
Observation of Hofstadter butterfly and topological edge states in reconfigurable quasi-periodic acoustic crystals
Publisher: Springer Science and Business Media LLC
Date: 06-06-2019
DOI: 10.1038/S42005-019-0151-7
Abstract: The emergence of a fractal energy spectrum is the quintessence of the interplay between two periodic parameters with incommensurate length scales. crystals can emulate such interplay and also exhibit a topological bulk-boundary correspondence, enabled by their nontrivial topology in virtual dimensions. Here we propose, fabricate and experimentally test a reconfigurable one-dimensional (1D) acoustic array, in which the resonant frequencies of each element can be independently fine-tuned by a piston. We map experimentally the full Hofstadter butterfly spectrum by measuring the acoustic density of states distributed over frequency while varying the long-range order of the array. Furthermore, by adiabatically changing the phason of the array, we map topologically protected fractal boundary states, which are shown to be pumped from one edge to the other. This reconfigurable crystal serves as a model for future extensions to electronics, photonics and mechanics, as well as to quasi-crystalline systems in higher dimensions.
Adiabatic topological photonic interfaces
Publisher: Springer Science and Business Media LLC
Date: 02-08-2023
DOI: 10.1038/S41467-023-40238-5
Abstract: Topological phases of matter have been attracting significant attention across erse fields, from inherently quantum systems to classical photonic and acoustic metamaterials. In photonics, topological phases offer resilience and bring novel opportunities to control light with pseudo-spins. However, topological photonic systems can suffer from limitations, such as breakdown of topological properties due to their symmetry-protected origin and radiative leakage. Here we introduce adiabatic topological photonic interfaces, which help to overcome these issues. We predict and experimentally confirm that topological metasurfaces with slowly varying synthetic gauge fields significantly improve the guiding features of spin-Hall and valley-Hall topological structures commonly used in the design of topological photonic devices. Adiabatic variation in the domain wall profiles leads to the delocalization of topological boundary modes, making them less sensitive to details of the lattice, perceiving the structure as an effectively homogeneous Dirac metasurface. As a result, the modes showcase improved bandgap crossing, longer radiative lifetimes and propagation distances.
Nonlocal Metasurfaces for Optical Signal Processing
Publisher: American Physical Society (APS)
Date: 24-10-2018
All-optical nonreciprocity due to valley polarization pumping in transition metal dichalcogenides
Publisher: Springer Science and Business Media LLC
Date: 18-06-2021
DOI: 10.1038/S41467-021-24138-0
Abstract: Nonreciprocity and nonreciprocal optical devices play a vital role in modern photonic technologies by enforcing one-way propagation of light. Here, we demonstrate an all-optical approach to nonreciprocity based on valley-selective response in transition metal dichalcogenides (TMDs). This approach overcomes the limitations of magnetic materials and it does not require an external magnetic field. We provide experimental evidence of photoinduced nonreciprocity in a monolayer WS 2 pumped by circularly polarized (CP) light. Nonreciprocity stems from valley-selective exciton population, giving rise to nonlinear circular dichroism controlled by CP pump fields. Our experimental results reveal a significant effect even at room temperature, despite considerable intervalley-scattering, showing promising potential for practical applications in magnetic-free nonreciprocal platforms. As an ex le, here we propose a device scheme to realize an optical isolator based on a pass-through silicon nitride (SiN) ring resonator integrating the optically biased TMD monolayer.
Fundamentals of Waveguide and Antenna Applications Involving DNG and SNG Metamaterials
Publisher: Wiley
Date: 12-05-2006
Floquet topological insulators for sound
Publisher: Springer Science and Business Media LLC
Date: 17-06-2016
DOI: 10.1038/NCOMMS11744
Abstract: The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity against structural defects and disorder. So far, these fascinating properties have been obtained relying on moving media, which may introduce noise and absorption losses, hindering the practical potential of topological acoustics. Here we overcome these limitations by modulating in time the acoustic properties of a lattice of resonators, introducing the concept of acoustic Floquet topological insulators. We show that acoustic waves provide a fertile ground to apply the anomalous physics of Floquet topological insulators, and demonstrate their relevance for a wide range of acoustic applications, including broadband acoustic isolation and topologically protected, nonreciprocal acoustic emitters.
Scalable Metagrating for Efficient Ultrasonic Focusing
Publisher: American Physical Society (APS)
Date: 06-12-2021
Topological polaritons and photonic magic angles in twisted α-MoO3 bilayers
Publisher: Springer Science and Business Media LLC
Date: 11-06-2020
Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-05-2018
Abstract: We demonstrate a robust pseudospin- and valley-polarized one-way Klein tunneling and topological edge states.
Non-local computing metasurfaces performing mathematical operations
Publisher: OSA
Date: 2018
Demonstration of higher-order topological States in photonic kagome lattice with next-nearest-neighbour coupling
Publisher: AIP Publishing
Date: 2020
DOI: 10.1063/5.0032066
Enhanced light–matter interaction in two-dimensional transition metal dichalcogenides
Publisher: IOP Publishing
Date: 08-03-2022
Abstract: Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials, such as MoS 2 , WS 2 , MoSe 2 , and WSe 2 , have received extensive attention in the past decade due to their extraordinary electronic, optical and thermal properties. They evolve from indirect bandgap semiconductors to direct bandgap semiconductors while their layer number is reduced from a few layers to a monolayer limit. Consequently, there is strong photoluminescence in a monolayer (1L) TMDC due to the large quantum yield. Moreover, such monolayer semiconductors have two other exciting properties: large binding energy of excitons and valley polarization. These properties make them become ideal materials for various electronic, photonic and optoelectronic devices. However, their performance is limited by the relatively weak light–matter interactions due to their atomically thin form factor. Resonant nanophotonic structures provide a viable way to address this issue and enhance light–matter interactions in 2D TMDCs. Here, we provide an overview of this research area, showcasing relevant applications, including exotic light emission, absorption and scattering features. We start by overviewing the concept of excitons in 1L-TMDC and the fundamental theory of cavity-enhanced emission, followed by a discussion on the recent progress of enhanced light emission, strong coupling and valleytronics. The atomically thin nature of 1L-TMDC enables a broad range of ways to tune its electric and optical properties. Thus, we continue by reviewing advances in TMDC-based tunable photonic devices. Next, we survey the recent progress in enhanced light absorption over narrow and broad bandwidths using 1L or few-layer TMDCs, and their applications for photovoltaics and photodetectors. We also review recent efforts of engineering light scattering, e.g., inducing Fano resonances, wavefront engineering in 1L or few-layer TMDCs by either integrating resonant structures, such as plasmonic/Mie resonant metasurfaces, or directly patterning monolayer/few layers TMDCs. We then overview the intriguing physical properties of different van der Waals heterostructures, and their applications in optoelectronic and photonic devices. Finally, we draw our opinion on potential opportunities and challenges in this rapidly developing field of research.
Rydberg atom-based field sensing enhancement using a split-ring resonator
Publisher: AIP Publishing
Date: 16-05-2022
DOI: 10.1063/5.0088532
Abstract: We investigate the use of a split-ring resonator (SRR) incorporated with an atomic-vapor cell to improve the sensitivity and the minimal detectable electric (E) field of Rydberg atom-based sensors. In this approach, a sub-wavelength SRR is placed around an atomic vapor-cell filled with cesium atoms for E-field measurements at 1.3 GHz. The SRR provides a factor of 100 in the enhancement of the E-field measurement sensitivity. Using electromagnetically induced transparency (EIT) with Aulter–Townes splitting, E-field measurements down to 5 mV/m are demonstrated with the SRR, while in the absence of the SRR, the minimal detectable field is 500 mV/m. We demonstrate that by combining EIT with a heterodyne Rydberg atom-based mixer approach, the SRR allows for a sensitivity of 5.5 μV/mHz, which is two-orders of magnitude improvement in sensitivity than when the SRR is not used.
Edge-oriented and steerable hyperbolic polaritons in anisotropic van der Waals nanocavities
Publisher: Springer Science and Business Media LLC
Date: 30-11-2020
DOI: 10.1038/S41467-020-19913-4
Abstract: Highly confined and low-loss polaritons are known to propagate isotropically over graphene and hexagonal boron nitride in the plane, leaving limited degrees of freedom in manipulating light at the nanoscale. The emerging family of biaxial van der Waals materials, such as α-MoO 3 and V 2 O 5 , support exotic polariton propagation, as their auxiliary optical axis is in the plane. Here, exploiting this strong in-plane anisotropy, we report edge-tailored hyperbolic polaritons in patterned α-MoO 3 nanocavities via real-space nanoimaging. We find that the angle between the edge orientation and the crystallographic direction significantly affects the optical response, and can serve as a key tuning parameter in tailoring the polaritonic patterns. By shaping α-MoO 3 nanocavities with different geometries, we observe edge-oriented and steerable hyperbolic polaritons as well as forbidden zones where the polaritons detour. The lifetime and figure of merit of the hyperbolic polaritons can be regulated by the edge aspect ratio of nanocavity.
Demonstration of a third-order hierarchy of topological states in a three-dimensional acoustic metamaterial
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-03-2020
Abstract: A 3D acoustic higher-order topological metamaterial supports a hierarchy of topological boundary states.
Visible Light, Wide-Angle Graded Metasurface for Back Reflection
Publisher: American Chemical Society (ACS)
Date: 03-02-2017
Spectroscopy of topological photonic states in dielectric metasurfaces
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4998043
Observation of localized magnetic plasmon skyrmions
Publisher: Springer Science and Business Media LLC
Date: 10-01-2022
DOI: 10.1038/S41467-021-27710-W
Abstract: Optical skyrmions have recently been constructed by tailoring vectorial near-field distributions through the interference of multiple surface plasmon polaritons, offering promising features for advanced information processing, transport and storage. Here, we provide experimental demonstration of electromagnetic skyrmions based on magnetic localized spoof plasmons (LSP) showing large topological robustness against continuous deformations, without stringent external interference conditions. By directly measuring the spatial profile of all three vectorial magnetic fields, we reveal multiple π-twist target skyrmion configurations mapped to multi-resonant near-equidistant LSP eigenmodes. The real-space skyrmion topology is robust against deformations of the meta-structure, demonstrating flexible skyrmionic textures for arbitrary shapes. The observed magnetic LSP skyrmions pave the way to ultra-compact and robust plasmonic devices, such as flexible sensors, wearable electronics and ultra-compact antennas.
Resonant Metagratings for Spectral and Angular Control of Light for Colored Rooftop Photovoltaics
Publisher: American Chemical Society (ACS)
Date: 03-04-2020
Generalized antireflection coatings for complex bulk metamaterials
Publisher: American Physical Society (APS)
Date: 24-05-2016
Breaking temporal symmetries in acoustic metamaterials
Publisher: IEEE
Date: 09-2015
Suppression of long-range collective effects in meta-surfaces formed by plasmonic antenna pairs
Publisher: The Optical Society
Date: 24-10-2011
DOI: 10.1364/OE.19.022142
Extreme Diffraction Control in Metagratings Leveraging Bound States in the Continuum and Exceptional Points
Publisher: Wiley
Date: 06-03-2022
Abstract: Coupled resonances in non‐Hermitian systems can lead to exotic optical features, such as bound states in the continuum (BICs) and exceptional points (EPs), which have been recently emerged as powerful tools to control the propagation and scattering of light. Yet, similar tools to control diffraction and engineer spatial wavefronts have remained elusive. Here, it is shown that, by operating a metagrating around BICs and EPs, it is possible to achieve an extreme degree of control over coupling to different diffraction orders. Subwavelength metallic slit arrays stacked on a metal‐insulator‐metal waveguide, enabling a careful control of the coupling between localized and guided modes are explored. By tuning the coupling strength from weak to strong, the overall spectral response can be tailored and the emergence of singular features, like BICs and EPs can be enabled. Perfect unitary diffraction efficiency with large spectrum selectivity is achieved around these singular features, with promising applications for selective wavefront shaping, filtering, and sensing.
Combined Metagratings for Efficient Broad-Angle Scattering Metasurface
Publisher: American Chemical Society (ACS)
Date: 18-03-2019
Topologically robust sound propagation in an angular-momentum-biased graphene-like resonator lattice
Publisher: Springer Science and Business Media LLC
Date: 06-10-2015
DOI: 10.1038/NCOMMS9260
Abstract: Topological insulators do not allow conduction in the bulk, yet they support edge modes that travel along the boundary only in one direction, determined by the carried electron spin, with inherent robustness to defects and disorder. Topological insulators have inspired analogues in photonics and optics, in which one-way edge propagation in topologically protected two-dimensional materials is achieved breaking time-reversal symmetry with a magnetic bias. Here, we introduce the concept of topological order in classical acoustics, realizing robust topological protection and one-way edge propagation of sound in a suitably designed resonator lattice biased with angular momentum, forming the acoustic analogue of a magnetically biased graphene layer. Extending the concept of an acoustic nonreciprocal circulator based on angular-momentum bias, time-reversal symmetry is broken here using moderate rotational motion of air within each element of the lattice, which takes the role of the electron spin in determining the direction of modal edge propagation.
Saturable Time-Varying Mirror Based on an Epsilon-Near-Zero Material
Publisher: American Physical Society (APS)
Date: 21-11-2022
Photonic Dirac cavities with spatially varying mass term
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-03-2023
Abstract: In recent years, photonics has proven itself as an excellent platform for emulation of relativistic phenomena. Here, we show an ex le of relativistic-like trapping in photonic system that realizes Dirac-like dispersion with spatially inhomogeneous mass term. The modes trapped by such cavities, their energy levels, and corresponding orbitals are then characterized through optical imaging in real and momentum space. The fabricated cavities host a hierarchy of photonic modes with distinct radiation profiles directly analogous to various atomic orbitals endowed with unique characteristics, such as pseudo-particle-hall symmetry and spin degeneracy, and they carry topological charge which gives rise to radiative profiles with angular momentum. We demonstrate that these modes can be directionally excited by pseudo-spin–polarized boundary states. In addition to the fundamental interest in the structure of these pseudo-relativistic orbitals, the proposed system offers a route for designing new types of nanophotonic devices, spin-full resonators and topological light sources compatible with integrated photonics platforms.
Ultrahigh-Q Guided Mode Resonances in An All-dielectric Metasurface
Publisher: Research Square Platform LLC
Date: 30-06-2022
DOI: 10.21203/RS.3.RS-1755479/V1
Abstract: High quality (Q) factor optical resonators are indispensable for many photonic devices. While very large Q-factors can be obtained theoretically in guided mode settings, free-space implementations suffer from various limitations on the narrowest possible linewidth in real experiments. In these devices, the largest Q-factors are hindered by radiation loss induced by fabrication disorder. Complex photonic designs have been explored to enhance this response through either delicate engineering the topological features or carefully breaking symmetries. Here, we put forward a simple strategy to enable ultrahigh-Q guided-mode resonances in all-dielectric metasurfaces without breaking symmetry or carefully engineering topological quantities. We introduce a patterned perturbation layer on top of a multilayer waveguide system, aimed at exciting tailored guided-mode resonances from free space. We demonstrate that the associated Q-factors are inversely proportional to the perturbation squared, suggesting a simple way of achieving extremely high-Q resonances as the perturbation is reduced. The resonant wavelength can be conveniently tuned through material or structural parameters, such as the thickness and refractive index or the metasurface period, within a robust design strategy amenable for implementation in various platforms. We experimentally demonstrate such high-Q resonances at telecom wavelengths by fabricating a low-index photoresist layer photonic crystal slab on top of a 220nm top layer SOI substrate. The measurements show Q-factors up to 2.39x10 5 , comparable to the largest Q-factor obtained by topological engineering, while the resonant wavelength is tuned by varying the lattice constant of the top perturbation layer. Our results hold great promise for exciting applications, such as sensors and filters.
Nonlinear topological transitions over a metasurface
Publisher: American Physical Society (APS)
Date: 19-12-2019
Sensibilidad antimicrobiana y detección de genes de virulencia en aislados clínicos de Shigella spp
Publisher: Pontifica Universidad Catolica del Ecuador
Date: 15-08-2017
DOI: 10.26807/REMCB.V36I1-2.266
Abstract: El género Shigella comprende las especies S. flexneri, S. sonnei, S. boydii y S. dysenteriae, bacterias responsables de la shigelosis. Éste género se caracteriza por la presencia de multirresistencia a antibióticos y una variedad de factores de virulencia que permiten la infección al hospedero. El objetivo de este estudio fue establecer la sensibilidad antimicrobiana y detectar genes de virulencia “Invasion plasmid antigen H“, ipaH “Invasion-associated locus”, ial “Shigella toxin” Stx “Shigella enterotoxin 1A”, set1A y “Shigella enterotoxin 1B”, set1B en aislados clínicos de Shigella spp. Se analizaron 79 aislados obtenidos de Zurita & Zurita Laboratorios y del hospital Vozandes. Mediante serotipificación, se registraron tres especies: S. flexneri (64.6 %), S. sonnei (29.1 %), y S. boydii (6.3 %). La sensibilidad antimicrobiana siguió el método de difusión con disco según las recomendaciones del Clinical and Laboratory Standars Institute (CLSI). La resistencia obtenida fue a tetraciclina (96.20 %), icilina (94.9 %), trimetoprima/sulfametoxazol (86.1 %) y cloranfenicol (84.8 %). No se registraron aislados de Shigella con resistencia a ciprofloxacino, azitromicina ni a ceftriaxona. Se determinó la presencia de genes de virulencia por la reacción en cadena de la polimerasa (PCR). Se determinó una alta prevalencia de los genes ipaH (91.1 %) e ial (82.3 %), los genes codificantes de enterotoxina 1 (set1A y set1B) se encontraron en un 35.4 %. Los resultados obtenidos demuestran la existencia de multiresistencia a antibióticos y cepas virulentas.
Planar chiral metasurfaces with maximal and tunable chiroptical response driven by bound states in the continuum
Publisher: Research Square Platform LLC
Date: 26-01-2022
DOI: 10.21203/RS.3.RS-1194502/V1
Abstract: Optical metasurfaces with high-Q chiral resonances can boost light-matter interaction for various applications of chiral response for ultrathin, active, and nonlinear metadevices. Usually, such metasurfaces require sophisticated depth-resolved nanofabrication to realize subwavelength stereo-nanostructures, posing overwhelming challenges, especially in the short-wavelength range. Here, we suggest a novel planarized design of chiral metasurfaces supporting bound states in the continuum (BICs), and demonstrate experimentally chiroptical responses with record-high Q-factors (Q=390) and near-perfect circular dichroism (CD=0.93) at optical frequencies. The symmetry-reduced meta-atoms are highly birefringent and support winding elliptical eigen-polarizations with opposite helicity surrounding the BIC polarization singularity, providing a convenient way for achieving maximal planar chirality tuned by either broken in-plane symmetry or changing illumination direction. Such sharply resonant chirality realized in planar metasurfaces promises various practical applications in classical and quantum optics including chiral sensing, enantiomer selection, and chiral quantum emitters.
Topological insulators based on coupled nonlinear resonators
Publisher: IEEE
Date: 08-2017
High-Index Dielectric Metasurfaces Performing Mathematical Operations
Publisher: American Chemical Society (ACS)
Date: 11-2019
Nanophotonics: Shrinking light-based technology
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-2015
Abstract: The study of light at the nanoscale has become a vibrant field of research, as researchers now master the flow of light at length scales far below the optical wavelength, largely surpassing the classical limits imposed by diffraction. Using metallic and dielectric nanostructures precisely sculpted into two-dimensional (2D) and 3D nanoarchitectures, light can be scattered, refracted, confined, filtered, and processed in fascinating new ways that are impossible to achieve with natural materials and in conventional geometries. This control over light at the nanoscale has not only unveiled a plethora of new phenomena but has also led to a variety of relevant applications, including new venues for integrated circuitry, optical computing, solar, and medical technologies, setting high expectations for many novel discoveries in the years to come.
Probing the Band Structure of Topological Silicon Photonic Lattices in the Visible Spectrum
Publisher: American Physical Society (APS)
Date: 21-03-2019
Single-Negative, Double-Negative, and Low-index Metamaterials and their Electromagnetic Applications
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2007
Dual-Polarization Analog 2D Image Processing with Nonlocal Metasurfaces
Publisher: American Chemical Society (ACS)
Date: 09-06-2020
Non-reciprocal parity-time symmetry breaking based on magneto-optical and gain/loss double ring resonators
Publisher: Optica Publishing Group
Date: 16-03-2022
DOI: 10.1364/OME.450821
Abstract: In this paper, we explore the operation of a nonreciprocal non-Hermitian system consisting of a lossy magneto-optical ring resonator coupled to another ring resonator with gain and loss, and we demonstrate that such a system can exhibit non-reciprocity-based broken parity-time (PT) symmetry and supports one-way exceptional points. The nonreciprocal PT-phase transition is analyzed with the use of both analytical tools based on coupled-mode theory and two-dimensional finite element method simulations. Our calculations show that the response of the system strongly depends on the regime of operation – broken or preserved PT-symmetry. This response is leveraged to show that the system can operate as an optical isolator or a one-way laser with functionality tuned by adjusting loss/gain in the second ring resonator. The proposed system can thus be promising for device applications such as magnetically or even optically switchable non-reciprocal devices and one-way micro-ring lasers.
Planar chiral metasurfaces with maximal and tunable chiroptical response driven by bound states in the continuum
Publisher: Springer Science and Business Media LLC
Date: 15-07-2022
DOI: 10.1038/S41467-022-31877-1
Abstract: Optical metasurfaces with high quality factors (Q-factors) of chiral resonances can boost substantially light-matter interaction for various applications of chiral response in ultrathin, active, and nonlinear metadevices. However, current approaches lack the flexibility to enhance and tune the chirality and Q-factor simultaneously. Here, we suggest a design of chiral metasurface supporting bound state in the continuum (BIC) and demonstrate experimentally chiroptical responses with ultra-high Q-factors and near-perfect circular dichroism (CD = 0.93) at optical frequencies. We employ the symmetry-reduced meta-atoms with high birefringence supporting winding elliptical eigenstate polarizations with opposite helicity. It provides a convenient way for achieving the maximal planar chirality tuned by either breaking in-plane structure symmetry or changing illumination angle. Beyond linear CD, we also achieved strong near-field enhancement CD and near-unitary nonlinear CD in the same planar chiral metasurface design with circular eigen-polarization. Sharply resonant chirality realized in planar metasurfaces promises various practical applications including chiral lasers and chiral nonlinear filters.
Roadmap on structured waves
Publisher: IOP Publishing
Date: 30-08-2023
Abstract: Structured waves are ubiquitous for all areas of wave physics, both classical and quantum, where the wavefields are inhomogeneous and cannot be approximated by a single plane wave. Even the interference of two plane waves, or of a single inhomogeneous (evanescent) wave, provides a number of nontrivial phenomena and additional functionalities as compared to a single plane wave. Complex wavefields with inhomogeneities in the litude, phase, and polarization, including topological––––– structures and singularities, underpin modern nanooptics and photonics, yet they are equally important, e.g. for quantum matter waves, acoustics, water waves, etc. Structured waves are crucial in optical and electron microscopy, wave propagation and scattering, imaging, communications, quantum optics, topological and non-Hermitian wave systems, quantum condensed-matter systems, optomechanics, plasmonics and metamaterials, optical and acoustic manipulation, and so forth. This Roadmap is written collectively by prominent researchers and aims to survey the role of structured waves in various areas of wave physics. Providing background, current research, and anticipating future developments, it will be of interest to a wide cross-disciplinary audience.
Observation of higher-order topological acoustic states protected by generalized chiral symmetry
Publisher: Springer Science and Business Media LLC
Date: 31-12-2018
DOI: 10.1038/S41563-018-0252-9
Abstract: Topological systems are inherently robust to disorder and continuous perturbations, resulting in dissipation-free edge transport of electrons in quantum solids, or reflectionless guiding of photons and phonons in classical wave systems characterized by topological invariants. Recently, a new class of topological materials characterized by bulk polarization has been introduced, and was shown to host higher-order topological corner states. Here, we demonstrate theoretically and experimentally that 3D-printed two-dimensional acoustic meta-structures can possess nontrivial bulk topological polarization and host one-dimensional edge and Wannier-type second-order zero-dimensional corner states with unique acoustic properties. We observe second-order topological states protected by a generalized chiral symmetry of the meta-structure, which are localized at the corners and are pinned to 'zero energy'. Interestingly, unlike the 'zero energy' states protected by conventional chiral symmetry, the generalized chiral symmetry of our three-atom sublattice enables their spectral overlap with the continuum of bulk states without leakage. Our findings offer possibilities for advanced control of the propagation and manipulation of sound, including within the radiative continuum.
All-dielectric topological meta-optics
Publisher: OSA
Date: 2018
Giant enhancement of Faraday rotation due to electromagnetically induced transparency in all-dielectric magneto-optical metasurfaces
Publisher: The Optical Society
Date: 11-04-2018
DOI: 10.1364/OL.43.001838
Internal Nanostructure Diagnosis with Hyperbolic Phonon Polaritons in Hexagonal Boron Nitride.
Publisher: American Chemical Society (ACS)
Date: 13-07-2018
DOI: 10.1021/ACS.NANOLETT.8B02162
Abstract: Imaging materials and inner structures with resolution below the diffraction limit has become of fundamental importance in recent years for a wide variety of applications. We report subdiffractive internal structure diagnosis of hexagonal boron nitride by exciting and imaging hyperbolic phonon polaritons. On the basis of their unique propagation properties, we are able to accurately locate defects in the crystal interior with nanometer resolution. The precise location, size, and geometry of the concealed defects are reconstructed by analyzing the polariton wavelength, reflection coefficient, and their dispersion. We have also studied the evolution of polariton reflection, transmission, and scattering as a function of defect size and photon frequency. The nondestructive high-precision polaritonic structure diagnosis technique introduced here can be also applied to other hyperbolic or waveguide systems and may be deployed in the next-generation biomedical imaging, sensing, and fine structure analysis.
Roadmap on optical metamaterials
Publisher: IOP Publishing
Date: 09-08-2016
Topological phases and nonreciprocal edge states in non-Hermitian Floquet insulators
Publisher: American Physical Society (APS)
Date: 29-07-2019
Near‐Field Characterization of Higher‐Order Topological Photonic States at Optical Frequencies
Publisher: Wiley
Date: 18-03-2021
Abstract: Higher‐order topological insulators (HOTIs) represent a new type of topological system, supporting boundary states localized over boundaries, two or more dimensions lower than the dimensionality of the system itself. Interestingly, photonic HOTIs can possess a richer physics than their original condensed matter counterpart, supporting conventional HOTI states based on tight‐binding coupling, and a new type of topological HOTI states enabled by long‐range interactions. Here, a new mechanism to establish all‐dielectric infrared HOTI metasurfaces exhibiting both types of HOTI states is proposed, supported by a topological transition accompanied by the emergence of topological Wannier‐type polarization. Two kinds of near‐field experimental studies are performed: i) the solid immersion spectroscopy and ii) near‐field imaging using scattering scanning near‐field optical microscopy to directly observe the topological transition and the emergence of HOTI states of two types. It is shown that the near‐field profiles indicate the displacement of the Wannier center across the topological transition leading to the topological dipole polarization and emergence of the topological boundary states. The proposed all‐dielectric HOTI metasurface offers a new approach to confine the optical field in micro‐ and nano‐scale topological cavities and thus paves the way to achieve a novel nanophotonic technology.
Higher-order topological states in photonic kagome crystals with long-range interactions
Publisher: Springer Science and Business Media LLC
Date: 09-12-2019
Transformation Wave Physics
Publisher: Jenny Stanford Publishing
Date: 18-11-2016
Acoustic meta-atom with experimentally verified maximum Willis coupling
Publisher: Springer Science and Business Media LLC
Date: 17-07-2019
DOI: 10.1038/S41467-019-10915-5
Abstract: Acoustic metamaterials are structures with exotic acoustic properties, with promising applications in acoustic beam steering, focusing, impedance matching, absorption and isolation. Recent work has shown that the efficiency of many acoustic metamaterials can be enhanced by controlling an additional parameter known as Willis coupling, which is analogous to bianisotropy in electromagnetic metamaterials. The magnitude of Willis coupling in a passive acoustic meta-atom has been shown theoretically to have an upper limit, however the feasibility of reaching this limit has not been experimentally investigated. Here we introduce a meta-atom with Willis coupling which closely approaches this theoretical limit, that is much simpler and less prone to thermo-viscous losses than previously reported structures. We perform two-dimensional experiments to measure the strong Willis coupling, supported by numerical calculations. Our meta-atom geometry is readily modeled analytically, enabling the strength of Willis coupling and its peak frequency to be easily controlled.
Synthetic Pseudo-Spin-Hall effect in acoustic metamaterials
Publisher: Springer Science and Business Media LLC
Date: 25-10-2022
DOI: 10.1038/S41467-022-34072-4
Abstract: While vector fields naturally offer additional degrees of freedom for emulating spin, acoustic pressure field is scalar in nature, and it requires engineering of synthetic degrees of freedom by material design. Here we experimentally demonstrate the control of sound waves by using two types of engineered acoustic systems, where synthetic pseudo-spin emerges either as a consequence of the evanescent nature of the field or due to lattice symmetry. First, we show that evanescent sound waves in perforated films possess transverse angular momentum locked to their propagation direction which enables their directional excitation. Second, we demonstrate that lattice symmetries of an acoustic kagome lattice also enable a synthetic transverse pseudo-spin locked to the linear momentum, enabling control of the propagation of modes both in the bulk and along the edges. Our results open a new degree of control of radiation and propagation of acoustic waves thus offering new design approaches for acoustic devices.
Ultrahigh-Q guided mode resonances in an All-dielectric metasurface
Publisher: Springer Science and Business Media LLC
Date: 10-06-2023
DOI: 10.1038/S41467-023-39227-5
Abstract: High quality(Q) factor optical resonators are indispensable for many photonic devices. While very large Q-factors can be obtained theoretically in guided-mode settings, free-space implementations suffer from various limitations on the narrowest linewidth in real experiments. Here, we propose a simple strategy to enable ultrahigh-Q guided-mode resonances by introducing a patterned perturbation layer on top of a multilayer-waveguide system. We demonstrate that the associated Q-factors are inversely proportional to the perturbation squared while the resonant wavelength can be tuned through material or structural parameters. We experimentally demonstrate such high-Q resonances at telecom wavelengths by patterning a low-index layer on top of a 220 nm silicon on insulator substrate. The measurements show Q-factors up to 2.39 × 10 5 , comparable to the largest Q-factor obtained by topological engineering, while the resonant wavelength is tuned by varying the lattice constant of the top perturbation layer. Our results hold great promise for exciting applications like sensors and filters.
Full‐Color Complex‐Amplitude Vectorial Holograms Based on Multi‐Freedom Metasurfaces
Publisher: Wiley
Date: 12-03-2020
Correcting the Fabry-Perot artifacts in metamaterial retrieval procedures
Publisher: American Physical Society (APS)
Date: 12-2011
Robust Multiplexing with Topolectrical Higher-Order Chern Insulators
Publisher: American Physical Society (APS)
Date: 12-06-2020
Nonlocal topological insulators: Deterministic aperiodic arrays supporting localized topological states protected by nonlocal symmetries
Publisher: Proceedings of the National Academy of Sciences
Date: 19-08-2021
Abstract: A concept of nonlocal topological phases of DAAs introduced here establishes a different direction in topological physics and offers approaches to emulate higher-dimensional topology in lower-dimensional systems. Our study also unveils opportunities to engineer topologically protected states in aperiodic systems and paves the path to application of resonances associated with such states, whose robustness is ensured by nonlocal symmetries of DAAs. In particular, the possibility to engineer multiple localized resonances via dimensional reduction and their unique features, such as precise spectral properties stemming from their topological nature, offers remarkable opportunities for practical applications, from robust resonators to sensors and aperiodic topological lasers.
Introduction to the Issue on Nanoplasmonics
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2013
Near-field imaging of spin-locked edge states in all-dielectric topological metasurfaces
Publisher: AIP Publishing
Date: 21-01-2019
DOI: 10.1063/1.5055601
Abstract: A new class of phenomena stemming from topological states of quantum matter has recently found a variety of analogies in classical systems. Spin-locking and one-way propagation have been shown to drastically alter scattering of electromagnetic waves, thus offering an unprecedented robustness to defects and disorder. Despite these successes, bringing these new ideas to practical grounds meets a number of serious limitations. In photonics, when it is crucial to implement topological photonic devices on a chip, two major challenges are associated with electromagnetic dissipation into heat and out-of-plane radiation into free space. Both these mechanisms may destroy the topological state and seriously affect the device performance. Here, we demonstrate experimentally that the topological order for light can be implemented in all-dielectric on-chip prototype metasurfaces, which mitigate the effect of Ohmic losses by using exclusively structured dielectric materials, and we reveal that coupling of the system to the radiative continuum does not affect topological properties. We demonstrate the spin-Hall effect of light for spin-polarized topological edge states through near-field spectroscopy measurements.
Femtosecond laser inscribed waveguide and micro-chip laser operation at 1.07μm in Yb3+ doped germanate glass
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2539820
Topological photonic crystals in the visible: design and angle-resolved characterization of the bulk and edge states
Publisher: OSA
Date: 2018
Far-field probing of leaky topological states in all-dielectric metasurfaces
Publisher: Springer Science and Business Media LLC
Date: 02-03-2018
DOI: 10.1038/S41467-018-03330-9
Abstract: Topological phase transitions in condensed matter systems give rise to exotic states of matter such as topological insulators, superconductors, and superfluids. Photonic topological systems open a whole new realm of research and technological opportunities, exhibiting a number of important distinctions from their condensed matter counterparts. Photonic modes can leak into free space, which makes it possible to probe topological photonic phases by spectroscopic means via Fano resonances. Based on this idea, we develop a technique to retrieve the topological properties of all-dielectric metasurfaces from the measured far-field scattering characteristics. Collected angle-resolved spectra provide the momentum-dependent frequencies and lifetimes of the photonic modes that enable the retrieval of the effective Hamiltonian and extraction of the topological invariant. Our results demonstrate how the topological states of open non-Hermitian systems can be explored via far-field measurements, thus paving a way to the design of metasurfaces with unique scattering characteristics controlled via topological effects.
Demonstration of a quantized acoustic octupole topological insulator
Publisher: Springer Science and Business Media LLC
Date: 30-04-2020
DOI: 10.1038/S41467-020-15705-Y
Abstract: Recently introduced quantized multipole topological insulators (QMTIs) reveal new types of gapped boundary states, which themselves represent lower-dimensional topological phases and host symmetry protected zero-dimensional corner states. Inspired by these predictions, tremendous efforts have been devoted to the experimental observation of quantized quadrupole topological phase. However, due to stringent requirements of anti-commuting reflection symmetries, it is challenging to achieve higher-order quantized multipole moments, such as octupole moments, in a three-dimensional structure. Here, we overcome this challenge, and experimentally realize the acoustic analogue of a quantized octupole topological insulator using negatively coupled resonators. We confirm by first-principle studies that our design possesses a quantized octupole topological phase, and experimentally demonstrate spectroscopic evidence of a hierarchy of boundary modes, observing 3 rd order topological corner states. Furthermore, we reveal topological phase transitions from higher- to lower-order multipole moments. Our work offers a pathway to explore higher-order topological states in 3D classical platforms.
Unidirectionally excited phonon polaritons in high-symmetry orthorhombic crystals
Publisher: American Association for the Advancement of Science (AAAS)
Date: 29-07-2022
Abstract: Advanced control over the excitation of ultraconfined polaritons—hybrid light and matter waves—empowers unique opportunities for many nanophotonic functionalities, e.g., on-chip circuits, quantum information processing, and controlling thermal radiation. Recent work has shown that highly asymmetric polaritons are directly governed by asymmetries in crystal structures. Here, we experimentally demonstrate extremely asymmetric and unidirectional phonon polariton (PhP) excitation via directly patterning high-symmetry orthorhombic van der Waals (vdW) crystal α-MoO 3 . This phenomenon results from symmetry breaking of momentum matching in polaritonic diffraction in vdW materials. We show that the propagation of PhPs can be versatile and robustly tailored via structural engineering, while PhPs in low-symmetry (e.g., monoclinic and triclinic) crystals are largely restricted by their naturally occurring permittivities. Our work synergizes grating diffraction phenomena with the extreme anisotropy of high-symmetry vdW materials, enabling unexpected control of infrared polaritons along different pathways and opening opportunities for applications ranging from on-chip photonics to directional heat dissipation.
Topological edge states in acoustic Kagome lattices
Publisher: IOP Publishing
Date: 16-05-2017
Experimental demonstration of higher-order topological states in photonic metasurfaces
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEO_AT.2020.JM3A.3
Abstract: We demonstrate and visualize the emergence of a topological transition and opening of a Dirac cone by directly exciting the bulk modes of the higher-order topological metasurface via solid-state immersion spectroscopy. The open nature of the metasurface is then utilized to directly image topological boundary states. We show that, while the topological domain walls host 1D edge states, their bending induces 0D higher-order topological modes confined to the corners.
Full-visible transmissive metagratings with large angle/wavelength/polarization tolerance
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR05745B
Abstract: We introduce a transmissive perfect diffraction metagrating towards high-performance full-visible holograms with large angle/wavelength olarization tolerance.
Self-induced topological transitions and edge states supported by nonlinear staggered potentials
Publisher: American Physical Society (APS)
Date: 07-04-2016
Reconfigurable Acoustic Metagrating for High-Efficiency Anomalous Reflection
Publisher: American Physical Society (APS)
Date: 29-06-2020
One-way photons in silicon
Publisher: Springer Science and Business Media LLC
Date: 09-2014
Nonlinear control of tunneling through an epsilon-near-zero channel
Publisher: American Physical Society (APS)
Date: 29-06-2009
Experimental observation of high-order topological corner states in 2D photonic Kagome lattice
Publisher: IEEE
Date: 09-2019
Nonlinear dynamic reciprocity
Publisher: Springer Science and Business Media LLC
Date: 28-05-2015
Optical isolator based on chiral light-matter interactions in a ring resonator integrating a dichroic magneto-optical material
Publisher: AIP Publishing
Date: 14-06-2021
DOI: 10.1063/5.0057558
Abstract: Nonreciprocal optical devices based on magneto-optical ferrites in their low-loss regimes have been widely investigated as a promising platform for integrated photonics. Nonreciprocity in such devices originates from circular birefringence, leading to frequency splitting of forward and backward modes and, as a result, nonreciprocal transmission. In this paper, we propose an alternative approach to realize nonreciprocal devices based on magneto-optical circular dichroism and relying on the very presence of optical absorption. Our approach relies on the phenomenon of spin-Hall effect of light, which gives rise to chiral near field interactions of light carrying transverse angular momentum with matter, which, in lossy regimes, yields a disparate absorption for forward and backward optical modes. As an ex le of practical application, we design an optical isolator based on ring resonator integrating Ce:YIG ferrite, and we demonstrate isolation near 880 nm absorption line due to the ionic electric dipole transition. A Ce:YIG film asymmetrically placed on the inner side of the ring yields different critical coupling conditions due to the chiral nature of evanescent light for forward and backward waves, leading to nonreciprocal absorption and transmission. The proposed approach to nonreciprocity may significantly broaden the possible choice of magneto-optical materials for nonreciprocal devices, enabling operation even in lossy regimes.
Experimental observation of spin-locked propagation of topological edge states in an open non-Hermitian metasurface
Publisher: IOP Publishing
Date: 09-2018
A topolectrical higher-order Chern insulator
Publisher: IEEE
Date: 27-09-2020
Topological edge states of distorted photonic Kagome lattices
Publisher: SPIE
Date: 24-08-2017
DOI: 10.1117/12.2273938
Interplay of Magnetic Responses in All-Dielectric Oligomers to Realize Magnetic Fano Resonances
Publisher: American Chemical Society (ACS)
Date: 18-05-2015
Self-induced topological protection in nonlinear circuit arrays
Publisher: Springer Science and Business Media LLC
Date: 09-03-2018
Topological phonon-polariton funneling in midinfrared metasurfaces
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-10-2021
Abstract: Understanding of the topological features of bandgaps has provided a route for engineering optical structures that exhibit directional propagation of light and are robust to defects. Guddala et al . combined a silicon-based topological photonic crystal with an atomic monolayer of hexagonal boron nitride (hBN). The topological features of the photonic crystal are coupled to the lattice vibrations of the hBN through the formation of phonon-polaritons. Funneling of helical infrared phonons along arbitrary pathways and across sharp bends provides the possibility of realizing directional heat dissipation along topologically resilient heat sinks. —ISO
Related Organisations
No related organisations have been discovered for Andrea Alu.
Related Funding Activities
Discovery Projects - Grant ID: DP150103736
Start Date: 2015
End Date: 12-2017
Amount: $544,100.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP200101708
Start Date: 09-2020
End Date: 09-2024
Amount: $400,000.00
Funder: Australian Research Council
View Funded ActivityARC Centres Of Excellence - Grant ID: CE200100010
Start Date: 2021
End Date: 12-2027
Amount: $34,935,112.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150103611
Start Date: 2015
End Date: 12-2018
Amount: $434,300.00
Funder: Australian Research Council
View Funded Activity