Publications by authors named "Yuri Kivshar"

361 Publications

From Fano to Quasi-BIC Resonances in Individual Dielectric Nanoantennas.

Nano Lett 2021 Feb 4;21(4):1765-1771. Epub 2021 Feb 4.

Nonlinear Physics Centre, Research School of Physics, Australian National University, Canberra 2601, Australia.

Sharp optical resonances in high-index dielectric nanostructures have recently attracted significant attention for their promising applications in nanophotonics. Fano resonances, as well as resonances associated with bound states in the continuum (BIC), have independently shown a great potential for applications in nanoscale lasers, sensors, and nonlinear optical devices. Here, we demonstrate experimentally a close connection between Fano and quasi-BIC resonances excited in individual dielectric nanoantennas. We analyze systematically the resonant response of AlGaAs nanoantennas pumped with a structured light in the near-infrared range. We trace a variation of the scattering spectrum that fully agrees with an analytical expression governed by a Fano parameter and observe directly a transition to a quasi-BIC resonance. Our results suggest a unified approach toward the analysis of sharp resonances in subwavelength nanostructures originating from strong coupling of optical modes that can provide high energy localization for enhanced light-matter interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c04660DOI Listing
February 2021

Full-Stokes Polarization Perfect Absorption with Diatomic Metasurfaces.

Nano Lett 2021 Jan 13;21(2):1090-1095. Epub 2021 Jan 13.

Centre of Translational Atomaterials (CTAM), Faculty of Science, Engineering and Technology and ▽The Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia.

Metamaterial-based perfect absorbers provide efficient ways for selective absorption of light with both linear or circular polarizations. Perfect absorption for an arbitrary polarization requires the development of subwavelength structures absorbing efficiently elliptically polarized light, but they remain largely unexplored. Here, we design and realize experimentally novel plasmonic metasurfaces for full-Stokes polarization perfect absorption in the mid-infrared. The metasurface unit cell consists of coupled anisotropic meta-atoms forming a diatomic metamolecule. The designed plasmonic metastructures provide a strong field enhancement by at least 1 order of magnitude higher than conventional perfect absorbers. In experiment, our plasmonic metasurfaces demonstrate sharp differentiation of spectral responses for an arbitrary pair of orthogonal polarization states (linear, circular, or elliptical) providing perfect absorption for one polarization with strong reflection for its counterpart. Our results suggest a novel route for efficient control of light polarization in metasurfaces offering numerous potential applications ranging from thermal imaging to chiral molecule detection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c04456DOI Listing
January 2021

Multipolar lasing modes from topological corner states.

Nat Commun 2020 Nov 13;11(1):5758. Epub 2020 Nov 13.

Department of Physics, Korea University, Seoul, 02841, Republic of Korea.

Topological photonics provides a fundamental framework for robust manipulation of light, including directional transport and localization with built-in immunity to disorder. Combined with an optical gain, active topological cavities hold special promise for a design of light-emitting devices. Most studies to date have focused on lasing at topological edges of finite systems or domain walls. Recently discovered higher-order topological phases enable strong high-quality confinement of light at the corners. Here, we demonstrate lasing action of corner states in nanophotonic topological structures. We identify several multipole corner modes with distinct emission profiles via hyperspectral imaging and discern signatures of non-Hermitian radiative coupling of leaky topological states. In addition, depending on the pump position in a large-size cavity, we generate selectively lasing from either edge or corner states within the topological bandgap. Our studies provide the direct observation of multipolar lasing and engineered collective resonances in active topological nanostructures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-020-19609-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7666194PMC
November 2020

Observation of Supercavity Modes in Subwavelength Dielectric Resonators.

Adv Mater 2021 Jan 9;33(1):e2003804. Epub 2020 Nov 9.

Department of Physics and Engineering, ITMO University, St. Petersburg, 197101, Russia.

Electromagnetic response of dielectric resonators with high refractive index is governed by optically induced electric and magnetic Mie resonances facilitating confinement of light with the amplitude enhancement. Traditionally, strong subwavelength trapping of light was associated only with plasmonic or epsilon-near-zero structures, which however suffer from material losses. Recently, an alternative localization mechanism was proposed allowing the trapping of light in individual subwavelength optical resonators with a high quality factor in the regime of a supercavity mode. Here, the experimental observation of the supercavity modes in subwavelength ceramic resonators in the radio-frequency range is presented. It is experimentally demonstrated that the regime of supercavity modes can be achieved via precise tuning of the resonator's dimensions. A huge growth of the unloaded quality factor is achieved with experimental values up to 1.25 × 10 , limited only by material losses of ceramics. It is revealed that the supercavity modes can be excited efficiently both in the near- and far-field. In both cases, the supercavity mode manifests itself explicitly as a Fano resonance with characteristic peculiarities of spectral shape and radiation pattern. A comparison of supercavities made of diversified materials for the visible, infrared, THz, and radio-frequency regimes is provided.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.202003804DOI Listing
January 2021

Metasurfaces with Maximum Chirality Empowered by Bound States in the Continuum.

Phys Rev Lett 2020 Aug;125(9):093903

Nonlinear Physics Centre, Research School of Physics, Australian National University, Canberra ACT 2601, Australia.

We demonstrate that rotationally symmetric chiral metasurfaces can support sharp resonances with the maximum optical chirality determined by precise shaping of bound states in the continuum (BICs). Being uncoupled from one circular polarization of light and resonantly coupled to its counterpart, a metasurface hosting the chiral BIC resonance exhibits a narrow peak in the circular dichroism spectrum with the quality factor limited by weak dissipation losses. We propose a realization of such chiral BIC metasurfaces based on pairs of dielectric bars and validate the concept of maximum chirality by numerical simulations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.125.093903DOI Listing
August 2020

Room-temperature lasing from nanophotonic topological cavities.

Light Sci Appl 2020 20;9:127. Epub 2020 Jul 20.

Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, ACT 2601 Australia.

The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual properties. Combined with an optical gain, topological photonic structures provide a novel platform for micro- and nanoscale lasers, which could benefit from nontrivial band topology and spatially localized gap states. Here, we propose and demonstrate experimentally active nanophotonic topological cavities incorporating III-V semiconductor quantum wells as a gain medium in the structure. We observe room-temperature lasing with a narrow spectrum, high coherence, and threshold behaviour. The emitted beam hosts a singularity encoded by a triade cavity mode that resides in the bandgap of two interfaced valley-Hall periodic photonic lattices with opposite parity breaking. Our findings make a step towards topologically controlled ultrasmall light sources with nontrivial radiation characteristics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41377-020-00350-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371636PMC
July 2020

Stimulated Raman Scattering from Mie-Resonant Subwavelength Nanoparticles.

Nano Lett 2020 Aug 1;20(8):5786-5791. Epub 2020 Jul 1.

Department of Physics and Engineering, ITMO University, St. Petersburg 197101, Russia.

Resonant dielectric structures have emerged recently as a new platform for subwavelength nonplasmonic photonics. It was suggested and demonstrated that magnetic and electric Mie resonances can enhance substantially many effects at the nanoscale including spontaneous Raman scattering. Here, we demonstrate stimulated Raman scattering (SRS) for isolated crystalline silicon (c-Si) nanoparticles and observe experimentally a transition from spontaneous to stimulated scattering manifested in a nonlinear growth of the signal intensity above a certain pump threshold. At the Mie resonance, the light gets confined into a low volume of the resonant mode with enhanced electromagnetic fields inside the c-Si nanoparticle due to its high refractive index, which leads to an overall strong SRS signal at low pump intensities. Our finding paves the way for the development of efficient Raman nanolasers for multifunctional photonic metadevices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c01646DOI Listing
August 2020

Quasi-BIC Resonant Enhancement of Second-Harmonic Generation in WS Monolayers.

Nano Lett 2020 Jul 22;20(7):5309-5314. Epub 2020 Jun 22.

School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia.

Atomically thin monolayers of transition metal dichalcogenides (TMDs) have emerged as a promising class of novel materials for optoelectronics and nonlinear optics. However, the intrinsic nonlinearity of TMD monolayers is weak, limiting their functionalities for nonlinear optical processes such as frequency conversion. Here we boost the effective nonlinear susceptibility of a TMD monolayer by integrating it with a resonant dielectric metasurface that supports pronounced optical resonances with high quality factors: bound states in the continuum (BICs). We demonstrate that a WS monolayer combined with a silicon metasurface hosting BICs exhibits enhanced second-harmonic intensity by more than 3 orders of magnitude relative to a WS monolayer on top of a flat silicon film of the same thickness. Our work suggests a pathway to employ high-index dielectric metasurfaces as hybrid structures for enhancement of TMD nonlinearities with applications in nonlinear microscopy, optoelectronics, and signal processing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c01603DOI Listing
July 2020

Room-Temperature Lasing from Mie-Resonant Nonplasmonic Nanoparticles.

ACS Nano 2020 Jul 8;14(7):8149-8156. Epub 2020 Jun 8.

Department of Physics and Engineering, ITMO University, Saint Petersburg 197101, Russia.

Subwavelength particles supporting Mie resonances underpin a strategy in nanophotonics for efficient control and manipulation of light by employing both an electric and a magnetic optically induced multipolar resonant response. Here, we demonstrate that monolithic dielectric nanoparticles made of CsPbBr halide perovskites can exhibit both efficient Mie-resonant lasing and structural coloring in the visible and near-IR frequency ranges. We employ a simple chemical synthesis with nearly epitaxial quality for fabricating subwavelength cubes with high optical gain and demonstrate single-mode lasing governed by the Mie resonances from nanocubes as small as 310 nm by the side length. These active nanoantennas represent the most compact room-temperature nonplasmonic nanolasers demonstrated until now.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.0c01468DOI Listing
July 2020

Bound States in the Continuum in Anisotropic Plasmonic Metasurfaces.

Nano Lett 2020 Sep 10;20(9):6351-6356. Epub 2020 Jun 10.

Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia.

The concept of optical bound states in the continuum (BICs) currently drives the field of dielectric resonant nanophotonics, providing an important physical mechanism for engineering high-quality (high-Q) optical resonances in high-index dielectric nanoparticles and structured dielectric metasurfaces. For structured metallic metasurfaces, realization of BICs remains a challenge associated with strong dissipative losses of plasmonic materials. Here, we suggest and realize experimentally supporting high-Q resonances governed by quasi-BIC collective resonant modes. Our metasurfaces are composed of arrays of vertically oriented double-pillar meta-molecules covered by a thin layer of gold. We engineer quasi-BIC modes and observe experimentally sharp resonances in mid-IR reflectance spectra. Our work suggests a direct route to boost the resonant field enhancement in plasmonic metasurfaces via combining a small effective mode volume of plasmonic systems with engineered high-Q resonances provided by the BIC physics, with multiple applications to enhance light-matter interaction for nano-optics and quantum photonics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c01752DOI Listing
September 2020

Nonlinear Imaging with All-Dielectric Metasurfaces.

Nano Lett 2020 Jun 12;20(6):4370-4376. Epub 2020 May 12.

Department of Physics, Paderborn University, 33098 Paderborn, Germany.

Nonlinear metasurfaces incorporate many of the functionalities of their linear counterparts such as wavefront shaping, but simultaneously they perform nonlinear optical transformations. This dual functionality leads to a rather unintuitive physical behavior which is still widely unexplored for many photonic applications. The nonlinear processes render some basic principles governing the functionality of linear metasurfaces. Exemplarily, the superposition principle and the geometric optics approximation become not directly applicable to nonlinear metasurfaces. On the other hand, nonlinear metasurfaces facilitate new phenomena that are not possible in the linear regime. Here, we study the imaging of objects through a dielectric nonlinear metalens. We illuminate objects by infrared light and record their generated images at the visible third-harmonic wavelengths. We revisit the classical lens theory and suggest a for nonlinear imaging, verified both experimentally and analytically. We also demonstrate experimentally higher-order spatial correlations facilitated by the nonlinear metalens, resulting in additional image features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c01105DOI Listing
June 2020

Photon-Mediated Localization in Two-Level Qubit Arrays.

Phys Rev Lett 2020 Mar;124(9):093604

Nonlinear Physics Centre, Research School of Physics, Australian National University, Canberra ACT 2601, Australia.

We predict the existence of a novel interaction-induced spatial localization in a periodic array of qubits coupled to a waveguide. This localization can be described as a quantum analogue of a self-induced optical lattice between two indistinguishable photons, where one photon creates a standing wave that traps the other photon. The localization is caused by the interplay between on-site repulsion due to the photon blockade and the waveguide-mediated long-range coupling between the qubits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.124.093604DOI Listing
March 2020

Ultrafast control of vortex microlasers.

Science 2020 02;367(6481):1018-1021

State Key Laboratory on Tunable Laser Technology, Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, China.

The development of classical and quantum information-processing technology calls for on-chip integrated sources of structured light. Although integrated vortex microlasers have been previously demonstrated, they remain static and possess relatively high lasing thresholds, making them unsuitable for high-speed optical communication and computing. We introduce perovskite-based vortex microlasers and demonstrate their application to ultrafast all-optical switching at room temperature. By exploiting both mode symmetry and far-field properties, we reveal that the vortex beam lasing can be switched to linearly polarized beam lasing, or vice versa, with switching times of 1 to 1.5 picoseconds and energy consumption that is orders of magnitude lower than in previously demonstrated all-optical switching. Our results provide an approach that breaks the long-standing trade-off between low energy consumption and high-speed nanophotonics, introducing vortex microlasers that are switchable at terahertz frequencies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aba4597DOI Listing
February 2020

Subwavelength dielectric resonators for nonlinear nanophotonics.

Science 2020 01;367(6475):288-292

Nonlinear Physics Center, Australian National University, Canberra ACT 2601, Australia.

Subwavelength optical resonators made of high-index dielectric materials provide efficient ways to manipulate light at the nanoscale through mode interferences and enhancement of both electric and magnetic fields. Such Mie-resonant dielectric structures have low absorption, and their functionalities are limited predominantly by radiative losses. We implement a new physical mechanism for suppressing radiative losses of individual nanoscale resonators to engineer special modes with high quality factors: optical bound states in the continuum (BICs). We demonstrate that an individual subwavelength dielectric resonator hosting a BIC mode can boost nonlinear effects increasing second-harmonic generation efficiency. Our work suggests a route to use subwavelength high-index dielectric resonators for a strong enhancement of light-matter interactions with applications to nonlinear optics, nanoscale lasers, quantum photonics, and sensors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aaz3985DOI Listing
January 2020

Inelastic Scattering of Photon Pairs in Qubit Arrays with Subradiant States.

Phys Rev Lett 2019 Dec;123(25):253601

Nonlinear Physics Centre, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

We develop a rigorous theoretical approach for analyzing inelastic scattering of photon pairs in arrays of two-level qubits embedded into a waveguide. Our analysis reveals a strong enhancement of the scattering when the energy of incoming photons resonates with the double-excited subradiant states. We identify the role of different double-excited states in the scattering, such as superradiant, subradiant, and twilight states, as a product of single-excitation bright and subradiant states. Importantly, the N-excitation subradiant states can be engineered only if the number of qubits exceeds 2N. Both the subradiant and twilight states can generate long-lived photon-photon correlations, paving the way to storage and processing of quantum information.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.123.253601DOI Listing
December 2019

Photosensitive chalcogenide metasurfaces supporting bound states in the continuum.

Opt Express 2019 Nov;27(23):33847-33853

We study, both theoretically and experimentally, tunable metasurfaces supporting sharp Fano-resonances inspired by optical bound states in the continuum. We explore the use of arsenic trisulfide (a photosensitive chalcogenide glass) having optical properties which can be finely tuned by light absorption at the post-fabrication stage. We select the resonant wavelength of the metasurface corresponding to the energy below the arsenic trisulfide bandgap, and experimentally control the resonance spectral position via exposure to the light of energies above the bandgap.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.27.033847DOI Listing
November 2019

Disorder-Immune Photonics Based on Mie-Resonant Dielectric Metamaterials.

Phys Rev Lett 2019 Oct;123(16):163901

ITMO University, St Petersburg 197101, Russia.

When the feature size of photonic structures becomes comparable or even smaller than the wavelength of light, the fabrication imperfections inevitably introduce disorder that may eliminate many functionalities of subwavelength photonic devices. Here we suggest a novel concept to achieve a robust band gap which can endure disorder beyond 30% as a result of the transition from photonic crystals to Mie-resonant metamaterials. By utilizing Mie-resonant metamaterials with high refractive index, we demonstrate photonic waveguides and cavities with strong robustness to position disorder, thus providing a novel approach to the band-gap-based nanophotonic devices with new properties and functionalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.123.163901DOI Listing
October 2019

Light trapping gets a boost.

Nature 2019 10;574(7779):491-492

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/d41586-019-03143-wDOI Listing
October 2019

Third-Harmonic Generation in Photonic Topological Metasurfaces.

Phys Rev Lett 2019 Sep;123(10):103901

Nonlinear Physics Centre, Australian National University, Canberra ACT 2601, Australia.

We study nonlinear effects in two-dimensional photonic metasurfaces supporting topologically protected helical edge states at the nanoscale. We observe strong third-harmonic generation mediated by optical nonlinearities boosted by multipolar Mie resonances of silicon nanoparticles. Variation of the pump-beam wavelength enables independent high-contrast imaging of either bulk modes or spin-momentum-locked edge states. We demonstrate topology-driven tunable localization of the generated harmonic fields and map the pseudospin-dependent unidirectional waveguiding of the edge states bypassing sharp corners. Our observations establish dielectric metasurfaces as a promising platform for the robust generation and transport of photons in topological photonic nanostructures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.123.103901DOI Listing
September 2019

All-Dielectric Active Terahertz Photonics Driven by Bound States in the Continuum.

Adv Mater 2019 Sep 31;31(37):e1901921. Epub 2019 Jul 31.

Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.

The remarkable emergence of all-dielectric meta-photonics governed by the physics of high-index dielectric materials offers a low-loss platform for efficient manipulation and subwavelength control of electromagnetic waves from microwaves to visible frequencies. Dielectric metasurfaces can focus electromagnetic waves, generate structured beams and vortices, enhance local fields for advanced sensing, and provide novel functionalities for classical and quantum technologies. Recent advances in meta-photonics are associated with the exploration of exotic electromagnetic modes called the bound states in the continuum (BICs), which offer a simple interference mechanism to achieve large quality factors (Q) through excitation of supercavity modes in dielectric nanostructures and resonant metasurfaces. Here, a BIC-driven terahertz metasurface with dynamic control of high-Q silicon supercavities that are reconfigurable at a nanosecond timescale is experimentally demonstrated. It is revealed that such supercavities enable low-power, optically induced terahertz switching and modulation of sharp resonances for potential applications in lasing, mode multiplexing, and biosensing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201901921DOI Listing
September 2019

Transverse Scattering and Generalized Kerker Effects in All-Dielectric Mie-Resonant Metaoptics.

Phys Rev Lett 2019 May;122(19):193905

ITMO University, St. Petersburg 197101, Russia.

All-dielectric resonant nanophotonics lies at the heart of modern optics and nanotechnology due to the unique possibilities to control scattering of light from high-index dielectric nanoparticles and metasurfaces. One of the important concepts of dielectric Mie-resonant nanophotonics is associated with the Kerker effect that drives the unidirectional scattering of light from nanoantennas and Huygens metasurfaces. Here we suggest and demonstrate experimentally a novel effect manifested in the nearly complete simultaneous suppression of both forward and backward scattered fields. This effect is governed by the Fano resonance of an electric dipole and off-resonant quadrupoles, providing necessary phases and amplitudes of the scattered fields to achieve the transverse scattering. We extend this concept to dielectric metasurfaces that demonstrate zero reflection with transverse scattering and strong field enhancement for resonant light filtering, nonlinear effects, and sensing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.122.193905DOI Listing
May 2019

Angle-multiplexed all-dielectric metasurfaces for broadband molecular fingerprint retrieval.

Sci Adv 2019 May 17;5(5):eaaw2871. Epub 2019 May 17.

Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.

Infrared spectroscopy resolves the structure of molecules by detecting their characteristic vibrational fingerprints. Subwavelength light confinement and nanophotonic enhancement have extended the scope of this technique for monolayer studies. However, current approaches still require complex spectroscopic equipment or tunable light sources. Here, we introduce a novel metasurface-based method for detecting molecular absorption fingerprints over a broad spectrum, which combines the device-level simplicity of state-of-the-art angle-scanning refractometric sensors with the chemical specificity of infrared spectroscopy. Specifically, we develop germanium-based high- metasurfaces capable of delivering a multitude of spectrally selective and surface-sensitive resonances between 1100 and 1800 cm. We use this approach to detect distinct absorption signatures of different interacting analytes including proteins, aptamers, and polylysine. In combination with broadband incoherent illumination and detection, our method correlates the total reflectance signal at each incidence angle with the strength of the molecular absorption, enabling spectrometer-less operation in a compact angle-scanning configuration ideally suited for field-deployable applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.aaw2871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6527437PMC
May 2019

Single-Mode Lasing from Imprinted Halide-Perovskite Microdisks.

ACS Nano 2019 Apr 18;13(4):4140-4147. Epub 2019 Mar 18.

ITMO University , St. Petersburg 197101 , Russia.

Halide-perovskite microlasers have demonstrated fascinating performance owing to their low-threshold lasing at room temperature and low-cost fabrication. However, being synthesized chemically, controllable fabrication of such microlasers remains challenging, and it requires template-assisted growth or complicated nanolithography. Here, we suggest and implement an approach for the fabrication of microlasers by direct laser ablation of a thin film on glass with donut-shaped femtosecond laser beams. The fabricated microlasers represent MAPbBr I microdisks with 760 nm thickness and diameters ranging from 2 to 9 μm that are controlled by a topological charge of the vortex beam. As a result, this method allows one to fabricate single-mode perovskite microlasers operating at room temperature in a broad spectral range (550-800 nm) with Q-factors up to 5500. High-speed fabrication and reproducibility of microdisk parameters, as well as a precise control of their location on a surface, make it possible to fabricate centimeter-sized arrays of such microlasers. Our finding is important for direct writing of fully integrated coherent light sources for advanced photonic and optoelectronic circuitry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.8b08948DOI Listing
April 2019

Engineering scattering patterns with asymmetric dielectric nanorods.

Opt Express 2018 Dec;26(25):32624-32630

By controlling interference of Mie resonance modes of various nanostructures, we can achieve a large number of nontrivial effects in nanophotonics. In this work, we propose a cylindrical structure in which the spectral overlap of the Mie-type modes can be controlled by drilling a hole parallel to the axis, thus changing unidirectional scattering. We further demonstrate that the scattering patterns can be tailored by rotating the structure to achieve almost arbitrary scattered wave direction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.26.032624DOI Listing
December 2018

Manipulation of Magnetic Dipole Emission from Eu with Mie-Resonant Dielectric Metasurfaces.

Nano Lett 2019 02 8;19(2):1015-1022. Epub 2019 Jan 8.

Institute of Applied Physics, Abbe Center of Photonics , Friedrich Schiller University Jena , 07745 Jena , Germany.

Mie-resonant high-index dielectric nanoparticles and metasurfaces have been suggested as a viable platform for enhancing both electric and magnetic dipole transitions of fluorescent emitters. While the enhancement of the electric dipole transitions by such dielectric nanoparticles has been demonstrated experimentally, the case of magnetic-dipole transitions remains largely unexplored. Here, we study the enhancement of spontaneous emission of Eu ions, featuring both electric and magnetic-dominated dipole transitions, by dielectric metasurfaces composed of Mie-resonant silicon nanocylinders. By coating the metasurfaces with a layer of an Eu doped polymer, we observe an enhancement of the Eu emission associated with the electric (at 610 nm) and magnetic-dominated (at 590 nm) dipole transitions. The enhancement factor depends systematically on the spectral proximity of the atomic transitions to the Mie resonances as well as their multipolar order, both controlled by the nanocylinder size. Importantly, the branching ratio of emission via the electric or magnetic transition channel can be modified by carefully designing the metasurface, where the magnetic dipole transition is enhanced more than the electric transition for cylinders with radii of about 130 nm. We confirm our observations by numerical simulations based on the reciprocity principle. Our results open new opportunities for bright nanoscale light sources based on magnetic transitions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.8b04268DOI Listing
February 2019

Reshaping the Second-Order Polar Response of Hybrid Metal-Dielectric Nanodimers.

Nano Lett 2019 02 10;19(2):877-884. Epub 2019 Jan 10.

Optical Nanomaterial Group, Institute for Quantum Electronics , ETH Zurich , 8093 Zurich , Switzerland.

We combine the field confinement of plasmonics with the flexibility of multiple Mie resonances by bottom-up assembly of hybrid metal-dielectric nanodimers. We investigate the electromagnetic coupling between nanoparticles in heterodimers consisting of gold and barium titanate (BaTiO or BTO) nanoparticles through nonlinear second-harmonic spectroscopy and polarimetry. The overlap of the localized surface plasmon resonant dipole mode of the gold nanoparticle with the dipole and higher-order Mie resonant modes in the BTO nanoparticle lead to the formation of hybridized modes in the visible spectral range. We employ the pick-and-place technique to construct the hybrid nanodimers with controlled diameters by positioning the nanoparticles of different types next to each other under a scanning electron microscope. Through linear scattering spectroscopy, we observe the formation of hybrid modes in the nanodimers. We show that the modes can be directly accessed by measuring the dependence of the second-harmonic generation (SHG) signal on the polarization and wavelength of the pump. We reveal both experimentally and theoretically that the hybridization of plasmonic and Mie-resonant modes leads to a strong reshaping of the SHG polarization dependence in the nanodimers, which depends on the pump wavelength. We compare the SHG signal of each hybrid nanodimer with the SHG signal of single BTO nanoparticles to estimate the enhancement factor due to the resonant mode coupling within the nanodimers. We report up to 2 orders of magnitude for the SHG signal enhancement compared with isolated BTO nanoparticles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.8b04089DOI Listing
February 2019

Nonlinear light generation in topological nanostructures.

Nat Nanotechnol 2019 02 17;14(2):126-130. Epub 2018 Dec 17.

Nonlinear Physics Centre, Australian National University, Canberra, Australian Capital Territory, Australia.

Topological photonics has emerged as a route to robust optical circuitry protected against disorder and now includes demonstrations such as topologically protected lasing and single-photon transport. Recently, nonlinear optical topological structures have attracted special theoretical interest, as they enable tuning of topological properties by a change in the light intensity and can break optical reciprocity to realize full topological protection. However, so far, non-reciprocal topological states have only been realized using magneto-optical materials and macroscopic set-ups with external magnets, which is not feasible for nanoscale integration. Here we report the observation of a third-harmonic signal from a topologically non-trivial zigzag array of dielectric nanoparticles and the demonstration of strong enhancement of the nonlinear photon generation at the edge states of the array. The signal enhancement is due to the interaction between the Mie resonances of silicon nanoparticles and the topological localization of the electric field at the edges. The system is also robust against various perturbations and structural defects. Moreover, we show that the interplay between topology, bi-anisotropy and nonlinearity makes parametric photon generation tunable and non-reciprocal. Our study brings nonlinear topological photonics concepts to the realm of nanoscience.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41565-018-0324-7DOI Listing
February 2019

Noninterleaved Metasurface for (2-1) Spin- and Wavelength-Encoded Holograms.

Nano Lett 2018 12 6;18(12):8016-8024. Epub 2018 Dec 6.

Department of Electrical and Computer Engineering , National University of Singapore , 4 Engineering Drive 3 , Singapore 117583 , Singapore.

Nanostructured metasurfaces demonstrate extraordinary capabilities to control light at the subwavelength scale, emerging as key optical components to physical realization of multitasked devices. Progress in multitasked metasurfaces has been witnessed in making a single metasurface multitasked by mainly resorting to extra spatial freedom, for example, interleaved subarrays, different angles. However, it imposes a challenge of suppressing the cross-talk among multiwavelength without the help of extra spatial freedom. Here, we introduce an entirely novel strategy of multitasked metasurfaces with noninterleaved single-size Si nanobrick arrays and minimalist spatial freedom demonstrating massive information on 6-bit encoded color holograms. The interference between electric dipole and magnetic dipole in individual Si nanobricks with in-plane orientation enables manipulating six bases of incident photons simultaneously to reconstructed 6-bit wavelength- and spin-dependent multicolor images. Those massively reconstructed images can be distinguished by pattern recognition. It opens an alternative route for integrated optics, data encoding, security encryption, and information engineering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.8b04246DOI Listing
December 2018

Asymmetric Metasurfaces with High-Q Resonances Governed by Bound States in the Continuum.

Phys Rev Lett 2018 Nov;121(19):193903

Nonlinear Physics Centre, Australian National University, Canberra ACT 2601, Australia.

We reveal that metasurfaces created by seemingly different lattices of (dielectric or metallic) meta-atoms with broken in-plane symmetry can support sharp high-Q resonances arising from a distortion of symmetry-protected bound states in the continuum. We develop a rigorous theory of such asymmetric periodic structures and demonstrate a link between the bound states in the continuum and Fano resonances. Our results suggest the way for smart engineering of resonances in metasurfaces for many applications in nanophotonics and metaoptics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.121.193903DOI Listing
November 2018

Quantum metasurface for multiphoton interference and state reconstruction.

Science 2018 09;361(6407):1104-1108

Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia.

Metasurfaces based on resonant nanophotonic structures have enabled innovative types of flat-optics devices that often outperform the capabilities of bulk components, yet these advances remain largely unexplored for quantum applications. We show that nonclassical multiphoton interferences can be achieved at the subwavelength scale in all-dielectric metasurfaces. We simultaneously image multiple projections of quantum states with a single metasurface, enabling a robust reconstruction of amplitude, phase, coherence, and entanglement of multiphoton polarization-encoded states. One- and two-photon states are reconstructed through nonlocal photon correlation measurements with polarization-insensitive click detectors positioned after the metasurface, and the scalability to higher photon numbers is established theoretically. Our work illustrates the feasibility of ultrathin quantum metadevices for the manipulation and measurement of multiphoton quantum states, with applications in free-space quantum imaging and communications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aat8196DOI Listing
September 2018