Ultra-high-Q resonances in plasmonic metasurfaces

AbstractPlasmonic nanostructures hold promise for the realization of ultra-thin sub-wavelength devices, reducing power operating thresholds and enabling nonlinear optical functionality in metasurfaces. However, this promise is substantially undercut by absorption introduced by resistive losses, causing the metasurface community to turn away from plasmonics in favour of alternative material platforms (e.g., dielectrics) that provide weaker field enhancement, but more tolerable losses. Here, we report a plasmonic metasurface with a quality-factor (Q-factor) of 2340 in the telecommunication C band by exploiting surface lattice resonances (SLRs), exceeding the record by an order of magnitude. Additionally, we show that SLRs retain many of the same benefits as localized plasmonic resonances, such as field enhancement and strong confinement of light along the metal surface. Our results demonstrate that SLRs provide an exciting and unexplored method to tailor incident light fields, and could pave the way to flexible wavelength-scale devices for any optical resonating application.

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Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.9.215 ◽

2018 ◽

Vol 9 ◽

pp. 2306-2314 ◽

Cited By ~ 23

Author(s):

Valerio F Gili ◽

Lavinia Ghirardini ◽

Davide Rocco ◽

Giuseppe Marino ◽

Ivan Favero ◽

...

Keyword(s):

Frequency Conversion ◽

Near Infrared ◽

Strong Field ◽

Second Harmonic ◽

Near Field ◽

Field Enhancement ◽

High Refractive Index ◽

Plasmonic Nanostructures ◽

Ohmic Losses ◽

Order Of Magnitude

Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode. Plasmonic nanostructures, on the other hand, remain the most promising solution to achieve strong local field confinement, especially in the NIR, where metals such as gold display relatively low losses. Results: We present a nonlinear hybrid antenna based on an AlGaAs nanopillar surrounded by a gold ring, which merges in a single platform the strong field confinement typically produced by plasmonic antennas with the high nonlinearity and low loss characteristics of dielectric nanoantennas. This platform allows enhancing the coupling of light to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna.

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Optical microfibers and nanofibers

Nanophotonics ◽

10.1515/nanoph-2013-0033 ◽

2013 ◽

Vol 2 (5-6) ◽

pp. 407-428 ◽

Cited By ~ 73

Author(s):

Xiaoqin Wu ◽

Limin Tong

Keyword(s):

Nonlinear Optics ◽

Fiber Optics ◽

Optical Fibers ◽

Optical Sensors ◽

Near Field ◽

Field Enhancement ◽

Atom Optics ◽

Near Field Optics ◽

Wavelength Scale ◽

Sub Wavelength

AbstractAs a combination of fiber optics and nanotechnology, optical microfibers and nanofibers (MNFs) have been emerging as a novel platform for exploring fiber-optic technology on the micro/nanoscale. Typically, MNFs taper drawn from glass optical fibers or bulk glasses show excellent surface smoothness, high homogeneity in diameter and integrity, which bestows these tiny optical fibers with low waveguiding losses and outstanding mechanical properties. Benefitting from their wavelength- or sub-wavelength-scale transverse dimensions, waveguiding MNFs exhibit a number of interesting properties, including tight optical confinement, strong evanescent fields, evident surface field enhancement and large and abnormal waveguide dispersion, which makes them ideal nanowaveguides for coherently manipulating light, and connecting fiber optics with near-field optics, nonlinear optics, plasmonics, quantum optics and optomechanics on the wavelength- or sub-wavelength scale. Based on optical MNFs, a variety of technological applications, ranging from passive micro-couplers and resonators, to active devices such as lasers and optical sensors, have been reported in recent years. This review is intended to provide an up-to-date introduction to the fabrication, characterization and applications of optical MNFs, with emphasis on recent progress in our research group. Starting from a brief introduction of fabrication techniques for physical drawing glass MNFs in Section 2, we summarize MNF optics including waveguiding modes, evanescent coupling, and bending loss of MNFs in Section 3. In Section 4, starting from a “MNF tree” that summarizes the applications of MNFs into 5 categories (waveguide & near field optics, nonlinear optics, plasmonics, quantum & atom optics, optomechanics), we go to details of typical technological applications of MNFs, including optical couplers, interferometers, gratings, resonators, lasers and sensors. Finally in Section 5 we present a brief summary of optical MNFs regarding their current challenges and future opportunities.

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Scanning-tunneling spectroscopy on conjugated polymer films

MRS Proceedings ◽

10.1557/proc-771-l4.3 ◽

2003 ◽

Vol 771 ◽

Author(s):

M. Kemerink ◽

S.F. Alvarado ◽

P.M. Koenraad ◽

R.A.J. Janssen ◽

H.W.M. Salemink ◽

...

Keyword(s):

Polymer Films ◽

Conjugated Polymer ◽

Three Dimensional ◽

Field Enhancement ◽

Direct Consequence ◽

Scanning Tunneling Spectroscopy ◽

Tunneling Spectroscopy ◽

Band Alignment ◽

Scanning Tunneling ◽

Order Of Magnitude

AbstractScanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current, which can amount to more than an order of magnitude, and can even change the polarity of the dominant charge carrier. As a direct consequence, the single-particle band gap and band alignment of the organic material can be directly obtained from tip height-voltage (z-V) curves, provided that the tip has a sufficiently sharp apex.

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Observing and controlling a Tamm plasmon at the interface with a metasurface

Nanophotonics ◽

10.1515/nanoph-2019-0514 ◽

2020 ◽

Vol 9 (4) ◽

pp. 897-903 ◽

Cited By ~ 4

Author(s):

Oleksandr Buchnev ◽

Alexandr Belosludtsev ◽

Victor Reshetnyak ◽

Dean R. Evans ◽

Vassili A. Fedotov

Keyword(s):

Liquid Crystal ◽

Metal Film ◽

Near Infrared ◽

Thin Metal Film ◽

Outer Side ◽

Spectral Position ◽

External Perturbations ◽

Dielectric Mirror ◽

Wavelength Scale ◽

Sub Wavelength

AbstractWe demonstrate experimentally that Tamm plasmons in the near infrared can be supported by a dielectric mirror interfaced with a metasurface, a discontinuous thin metal film periodically patterned on the sub-wavelength scale. More crucially, not only do Tamm plasmons survive the nanopatterning of the metal film but they also become sensitive to external perturbations as a result. In particular, by depositing a nematic liquid crystal on the outer side of the metasurface, we were able to red shift the spectral position of Tamm plasmon by 35 nm, while electrical switching of the liquid crystal enabled us to tune the wavelength of this notoriously inert excitation within a 10-nm range.

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High-Q dark hyperbolic phonon-polaritons in hexagonal boron nitride nanostructures

Nanophotonics ◽

10.1515/nanoph-2020-0048 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1457-1467 ◽

Cited By ~ 1

Author(s):

Georg Ramer ◽

Mohit Tuteja ◽

Joseph R. Matson ◽

Marcelo Davanco ◽

Thomas G. Folland ◽

...

Keyword(s):

Boron Nitride ◽

Cross Sections ◽

Hexagonal Boron Nitride ◽

Near Field ◽

High Q ◽

Surface Phonon Polaritons ◽

Previous Hypothesis ◽

Phonon Polaritons ◽

Field Reflectance ◽

Strong Confinement

AbstractThe anisotropy of hexagonal boron nitride (hBN) gives rise to hyperbolic phonon-polaritons (HPhPs), notable for their volumetric frequency-dependent propagation and strong confinement. For frustum (truncated nanocone) structures, theory predicts five, high-order HPhPs, sets, but only one set was observed previously with far-field reflectance and scattering-type scanning near-field optical microscopy. In contrast, the photothermal induced resonance (PTIR) technique has recently permitted sampling of the full HPhP dispersion and observing such elusive predicted modes; however, the mechanism underlying PTIR sensitivity to these weakly-scattering modes, while critical to their understanding, has not yet been clarified. Here, by comparing conventional contact- and newly developed tapping-mode PTIR, we show that the PTIR sensitivity to those weakly-scattering, high-Q (up to ≈280) modes is, contrary to a previous hypothesis, unrelated to the probe operation (contact or tapping) and is instead linked to PTIR ability to detect tip-launched dark, volumetrically-confined polaritons, rather than nanostructure-launched HPhPs modes observed by other techniques. Furthermore, we show that in contrast with plasmons and surface phonon-polaritons, whose Q-factors and optical cross-sections are typically degraded by the proximity of other nanostructures, the high-Q HPhP resonances are preserved even in high-density hBN frustum arrays, which is useful in sensing and quantum emission applications.

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Hyperspectral Molecular Orientation Mapping in Metamaterials

Applied Sciences ◽

10.3390/app11041544 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1544

Author(s):

Meguya Ryu ◽

Yoshiaki Nishijima ◽

Shinya Morimoto ◽

Naoki To ◽

Tomoki Hashizume ◽

...

Keyword(s):

Molecular Orientation ◽

Field Enhancement ◽

Chemical Mapping ◽

Metal Insulator ◽

Orientation Mapping ◽

Metal Insulator Metal ◽

Finger Printing ◽

Thermal Emitter ◽

Ir Bands ◽

Sub Wavelength

The four polarisation method is adopted for measurement of molecular orientation in dielectric nanolayers of metal-insulator-metal (MIM) metamaterials composed of gold nanodisks on polyimide and gold films. Hyperspectral mapping at the chemical finger printing spectral range of 4–20 μμm was carried out for MIM patterns of 1–2.5 μμm period (sub-wavelength). Overlay images taken at 0,π4,π2,3π4 orientation angles and subsequent baseline compensation are shown to be critically important for the interpretation of chemical mapping results and reduction of spurious artefacts. Light field enhancement in the 60-nm-thick polyimide (I in MIM) was responsible for strong absorption at the characteristic polyimide bands. Strong absorbance A at narrow IR bands can be used as a thermal emitter (emittance E=1−R), where R is the reflectance and A=1−R−T, where for optically thick samples the transmittance is T=0.

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Ultrahigh electric and magnetic near field enhancement based on high-Q whispering gallery modes in subwavelength all-dielectric resonators

Applied Physics Express ◽

10.35848/1882-0786/ac10a8 ◽

2021 ◽

Author(s):

Xiao-Jing Du ◽

Zhong-Jian Yang ◽

Ma-Long Hu ◽

Lin Ma ◽

Jun He

Keyword(s):

Near Field ◽

Field Enhancement ◽

Whispering Gallery Modes ◽

Dielectric Resonators ◽

High Q ◽

Whispering Gallery

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Optical Analysis of Hole Patterned Ag Nanoparticle Structure

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19382 ◽

2021 ◽

Vol 21 (8) ◽

pp. 4192-4199

Author(s):

Hyun-Ji Jeon ◽

Ji-Yeon Kim ◽

Jinnil Choi

Keyword(s):

Metal Nanoparticles ◽

Optical Transmission ◽

Incident Angle ◽

Incident Light ◽

Localized Surface Plasmon ◽

Optical Analysis ◽

Optical Noise ◽

Hole Configuration ◽

Nanoparticle Structure ◽

Sub Wavelength

A structure with periodic sub-wavelength nanohole patterns interacts with incident light and causes extraordinary optical transmission (EOT), with metal nanoparticles leading to localized surface plasmon resonance (LSPR) phenomena. To explore the effects of metal nanoparticles (NPs), optical analysis is performed for metal NP layers with periodic hole patterns. Investigation of Ag NP arrangements and comparisons with metal film structures are presented. Ag NP structures with different hole configuration are explored. Also, the effects of increasing light incident angle are investigated for metal NP structures where EOT peak at 460 nm wavelength is observed. Moreover, electric field distributions at each transmittance peak wavelengths and optical noise are analyzed. As a result, optical characteristics of metal NP structures are obtained and differences in resonance at each wavelength are highlighted.

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