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 symmetry-protected bound states in the continuum. develop rigorous theory such asymmetric periodic structures and demonstrate link between continuum Fano resonances. Our results suggest way for smart engineering many applications nanophotonics metaoptics.

All-dielectric nanophotonics is an exciting and rapidly developing area of nano-optics that utilizes the resonant behavior high-index low-loss dielectric nanoparticles to enhance light-matter interaction at nanoscale.When experimental implementation a specific all-dielectric nanostructure desired, two crucial factors have be considered: choice material fabrication method.The degree which various effects can enhanced relies on response chosen as well accuracy.Here, we provide overview...

Two-dimensional transition metal dichalcogenides (TMDCs) have recently become attractive semiconductor materials for several optoelectronic applications, such as photodetection, light harvesting, phototransistors, light-emitting diodes and lasers.They are particularly appealing because their bandgap lies in the visible near-IR range, they possess strong excitonic resonances, high oscillator strengths, valley-selective response.Coupling these to optical nanocavities enhances quantum yield of...

Abstract Photoconductive antennas are promising sources of terahertz radiation that is widely used for spectroscopy, characterization, and imaging biological objects, deep space studies, scanning surfaces, detection potentially hazardous substances. These compact allow generation both ultrabroadband pulses tunable continuous wave signals at room temperatures, with no need high‐power optical sources. However, such have relatively low energy conversion efficiency femtosecond laser or two close...

Two-dimensional semiconducting transition metal dichalcogenides (TMDCs) are extremely attractive materials for optoelectronic applications in the visible and near-infrared range. Coupling these to optical nanocavities enables advanced quantum optics nanophotonic devices. Here, we address issue of resonance coupling hybrid exciton-polariton structures based on single Si nanoparticles (NPs) coupled monolayer (1L)-WS2. We predict a strong regime with Rabi splitting energy exceeding 110 meV NP...

Abstract Advanced nanophotonics penetrates into other areas of science and technology, ranging from applied physics to biology, which results in many fascinating cross-disciplinary applications. It has been recently demonstrated that suitably engineered light-matter interactions at the nanoscale can overcome limitations today’s terahertz (THz) photoconductive antennas, making them one step closer practical implications. Here, we push forward this concept by comprehensive numerical...

Phase-change materials (PCMs) can switch between different crystalline states as a function of an external bias, offering pronounced change their dielectric function. To take full advantage these features for active photonics and information storage, stand-alone PCMs are not sufficient because the phase transition requires strong pump fields. Here, we explore hybrid metal–semiconductor core–shell nanoantennas loaded with PCMs, enabling drastic in scattering load changes its phase. Large...

Progress in light scattering engineering made it feasible to develop optical tweezers allowing capture, hold, and controllable displacement of submicrometer-size particles biological structures. However, the momentum conservation law imposes a fundamental restriction on pressure be repulsive paraxial fields, which severely limits capabilities optomechanical control, e.g., preventing attractive force acting sufficiently subwavelength molecules. Herein, we revisit issue forces by their...

Advances in the field of plasmonics, that is, nanophotonics based on optical properties metal nanostructures, paved way for development ultrasensitive biological sensors and other devices whose operating principles are localization an electromagnetic at nanometer scale. However, high dissipative losses nanostructures limit their performance many modern areas, including metasurfaces, metamaterials, interconnections, which required new combine them with refractive index dielectric...

We reveal that strong near-field coupling effects can be observed for dissimilar Mie-resonant dielectric meta-atoms and demonstrate both properties functionalities of high-index all-dielectric photonic structures controlled by engineering their geometry changing the distance between thus enhancing effective magnetic response. describe dimers, quadrumers, metasurfaces with a staggered structure optically induced moments (the so-called ”optical antiferromagnetism”) also toroidal response...

Abstract All-dielectric nanostructures have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts visible range is hindered by larger absorption coefficient, thus encouraging search alternative dielectrics nanophotonics. Here, we employ bandgap engineering synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features We observe...

Light scattering is one of the most established wave phenomena in optics, lying at heart light-matter interactions and crucial importance for nanophotonic applications. Passivity, causality, energy conservation imply strict bounds on degree control over from small particles, with implications performance many optical devices. Here, we demonstrate that these can be surpassed by considering excitations complex frequencies, yielding extreme responses as tailored nanoparticles reach a...

Launching and focusing phonon-polaritons present novel opportunities for low-loss guiding of subdiffractionally confined light at the nanoscale. Despite significant efforts to improve control in polaritonic media, focused spatially phonon-polariton waves have only been achieved in-plane anisotropic crystals (such as MoO$_3$) remain elusive isotropic hexagonal boron nitride). In this study, we a previously unexplored approach launching by employing hBN subwavelength resonators coupled gold...

Abstract Fano resonances in photonics arise from the coupling and interference between two resonant modes structures with broken symmetry. They feature an uneven narrow tunable lineshape are ideally suited for optical spectroscopy. Many resonance have been suggested nanophotonics over last ten years, but reconfigurability tailored design remain challenging. Herein, all‐optical “pick‐and‐place” approach aimed at assembling metamolecules of various geometries compositions a reconfigurable...

Surface-enhanced Raman spectroscopy (SERS) is a promising optical method for analyzing molecular samples of various nature. Most SERS studies are an applied nature, indicating serious potential their application in analytical practice. Dendritelike nanostructures have great SERS, but the lack predictable production significantly limits implementation. In this paper, controllably obtaining spatially separated, self-organized, and highly-branched silver dendrites via template synthesis pores...

High-index dielectric nanostructures are of particular interest for nonlinear nanophotonics, as they offer inherent magnetic-resonance-enhanced frequency conversion, and special types optical nonlinearity. This study proposes a nanoantenna consisting chain Si nanoparticles excited by quantum emitter, with radiation properties that can be tuned photoexcitation the electron-hole plasma. system is very sensitive to refractive indices nanoparticles---a fact exploited efficient all-optical...

Various clusters of metallic or dielectric nanoparticles can exhibit sharp Fano resonances originating from at least two modes interference different spectral width. However, for practical applications such as biosensing nonlinear nanophotonics, the fine-tuning is generally required. Here, we propose and demonstrate a novel type hybrid oligomers consisting asymmetric metal-dielectric (Au/Si) with resonance in visible range, which has predominantly magnetic origin. We both numerically...

The recently emerged concept of all-dielectric nanophotonics based on optical Mie resonances in high-index dielectric nanoparticles has proven to be a promising pathway boost light-matter interactions at the nanoscale. In this work, we discuss opportunities enabled by interaction nanoresonators with 2D transition metal dichalcogenides (2D TMDCs), leading weak and strong coupling regimes. We perform comprehensive analysis bright exciton photoluminescence (PL) enhancement from various TMDCs,...

Whispering-gallery-mode disk optical nanocavities with an enhancement factor up to 100 can be fabricated from bulk transition metal dichalcogenides having indirect bandgap using scanning probe lithography.

Metasurfaces are 2D planar lattices of nanoparticles that allow the manipulation incident light properties. Because attribute, metasurfaces promising candidates to replace bulky optical components. Traditionally, made from a periodic arrangement identical unit cells. However, more degrees freedom accessible if an increasing number structured cells combined. The present study explores type dielectric metasurface with complex supercells composed Mie-resonant nanocylinders and nanoscale rings....

Bound states in a continuum periodic photonic structures can be described as topological defects the k -space. These vortices migrate within Brillouin zone when geometrical parameters of system vary. In this study, we focus on migration polarization vortex across light line, from radiation to waveguide mode domain. We found that during transition, far-field transforms into near-field vortex. This is characterized by an enhanced localization evanescent field due vanishing fundamental Fourier...