scholarly journals Dielectric nanohole array metasurface for high-resolution near-field sensing and imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Donato Conteduca ◽  
Isabel Barth ◽  
Giampaolo Pitruzzello ◽  
Christopher P. Reardon ◽  
Emiliano R. Martins ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Limit Of Detection ◽  
Near Field ◽  
Nanohole Array ◽  
Trade Off ◽  
High Q ◽  
Biochemical Sensing ◽  
Optical Modes ◽  
Field Sensing ◽  
Q Factors

AbstractDielectric metasurfaces support resonances that are widely explored both for far-field wavefront shaping and for near-field sensing and imaging. Their design explores the interplay between localised and extended resonances, with a typical trade-off between Q-factor and light localisation; high Q-factors are desirable for refractive index sensing while localisation is desirable for imaging resolution. Here, we show that a dielectric metasurface consisting of a nanohole array in amorphous silicon provides a favourable trade-off between these requirements. We have designed and realised the metasurface to support two optical modes both with sharp Fano resonances that exhibit relatively high Q-factors and strong spatial confinement, thereby concurrently optimizing the device for both imaging and biochemical sensing. For the sensing application, we demonstrate a limit of detection (LOD) as low as 1 pg/ml for Immunoglobulin G (IgG); for resonant imaging, we demonstrate a spatial resolution below 1 µm and clearly resolve individual E. coli bacteria. The combined low LOD and high spatial resolution opens new opportunities for extending cellular studies into the realm of microbiology, e.g. for studying antimicrobial susceptibility.

scholarly journals Dielectric Nanohole Array Metasurface For High-Resolution Near-Field Sensing and Imaging

2020 ◽  
Author(s):  
Donato Conteduca ◽  
Isabel Barth ◽  
Giampaolo Pitruzzello ◽  
Christopher Reardon ◽  
Emiliano Martins ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Limit Of Detection ◽  
Near Field ◽  
Nanohole Array ◽  
Trade Off ◽  
High Q ◽  
Biochemical Sensing ◽  
Optical Modes ◽  
Field Sensing ◽  
Q Factors

Abstract Dielectric metasurfaces support resonances that are widely explored both for far-field wavefront shaping and for near-field sensing and imaging. Their design explores the interplay between localised Mie resonances and extended Bragg resonances, with a typical trade-off between Q-factor and light localisation; high Q-factors are desirable for refractive index sensing while localisation is desirable for imaging resolution. Here, we show that a dielectric metasurface consisting of a nanohole array in amorphous silicon provides a favourable trade-off between these requirements. We have designed and realised the metasurface to support two optical modes both with sharp Fano resonances that exhibit relatively high Q factors and strong spatial confinement, thereby concurrently optimizing the device for both imaging and biochemical sensing. For the sensing application, we demonstrate a limit of detection (LOD) as low as 1pg/ml for Immunoglobulin G (IgG); for resonant imaging, we demonstrate a spatial resolution below 1µm and clearly resolve individual E.coli bacteria. The combined low LOD and high spatial resolution opens new opportunities for extending cellular studies into the realm of microbiology, e.g. for studying antimicrobial susceptibility.

scholarly journals Scanning the plasmonic properties of a nanohole array with a single nanocrystal near-field probe

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 793-801
Author(s):  
Thi Phuong Lien Ung ◽  
Rabeb Jazi ◽  
Julien Laverdant ◽  
Remy Fulcrand ◽  
Gérard Colas des Francs ◽  
...  
Keyword(s):  
Electric Field ◽  
Local Density ◽  
Near Field ◽  
Normal Component ◽  
Electromagnetic Properties ◽  
Nanohole Array ◽  
Strong Concentration ◽  
Optical Modes ◽  
Plasmon Polaritons

AbstractThe electromagnetic properties of ordered hole nanostructures in very thin metal films are characterized using CdSe/CdS nanocrystals (NCs) as nanoprobes. The characterization of the local density of optical states (LDOS) on the nanostructure is possible by the measurement of their photoluminescence decay rate. Statistical measurements are performed in the far field to show the average increase of optical modes. A determinist approach using an active single NC nanoprobe in the near field gives access to a more precise characterization of the LDOS. The optical properties of the structure come from the coupling between localized surface plasmons created by the holes and surface plasmon polaritons. A strong concentration of optical modes is observed around the holes thanks to the active near-field nanoprobe. With different NC orientations, the strong influence of the component perpendicular to the surface in the very near field of the LDOS is observed. Finite differential time domain simulations of the different components of the electric field in the very near field of the structure confirm that the localization of the electric field around the holes is only due to the normal component as observed with the nanoprobe.

scholarly journals Near-Field Excitation of Bound States in the Continuum in All-Dielectric Metasurfaces through a Coupled Electric/Magnetic Dipole Model

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 998
Author(s):  
Diego R. Abujetas ◽  
José A. Sánchez-Gil
Keyword(s):  
Magnetic Dipole ◽  
Density Of States ◽  
Bound States ◽  
Local Density ◽  
Near Field ◽  
Field Pattern ◽  
Local Density Of States ◽  
Optical Modes ◽  
Source Excitation ◽  
The Continuum

Resonant optical modes arising in all-dielectric metasurfaces have attracted much attention in recent years, especially when so-called bound states in the continuum (BICs) with diverging lifetimes are supported. With the aim of studying theoretically the emergence of BICs, we extend a coupled electric and magnetic dipole analytical formulation to deal with the proper metasurface Green function for the infinite lattice. Thereby, we show how to excite metasurface BICs, being able to address their near-field pattern through point-source excitation and their local density of states. We apply this formulation to fully characterize symmetry-protected BICs arising in all-dielectric metasurfaces made of Si nanospheres, revealing their near-field pattern and local density of states, and, thus, the mechanisms precluding their radiation into the continuum. This formulation provides, in turn, an insightful and fast tool to characterize BICs (and any other leaky/guided mode) near fields in all-dielectric (and also plasmonic) metasurfaces, which might be especially useful for the design of planar nanophotonic devices based on such resonant modes.

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

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1457-1467 ◽  
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.

scholarly journals Improvement of spatial resolution by tilt correction in near-field scanning microwave microscopy

AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035114
Author(s):  
Xianfeng Zhang ◽  
Zhe Wu ◽  
Quansong Lan ◽  
Zhiliao Du ◽  
Quanxin Zhou ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Near Field ◽  
Tilt Correction ◽  
Microwave Microscopy ◽  
Scanning Microwave Microscopy ◽  
Near Field Scanning

scholarly journals Demonstration of an integrated nanophotonic chip-scale alkali vapor magnetometer using inverse design

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yoel Sebbag ◽  
Eliran Talker ◽  
Alex Naiman ◽  
Yefim Barash ◽  
Uriel Levy
Keyword(s):  
Spatial Resolution ◽  
Near Field ◽  
Computer Assisted ◽  
Experimental Characterization ◽  
Optical Isolation ◽  
New Concepts ◽  
On Chip ◽  
The Cost ◽  
Micrometer Scale

AbstractRecently, there has been growing interest in the miniaturization and integration of atomic-based quantum technologies. In addition to the obvious advantages brought by such integration in facilitating mass production, reducing the footprint, and reducing the cost, the flexibility offered by on-chip integration enables the development of new concepts and capabilities. In particular, recent advanced techniques based on computer-assisted optimization algorithms enable the development of newly engineered photonic structures with unconventional functionalities. Taking this concept further, we hereby demonstrate the design, fabrication, and experimental characterization of an integrated nanophotonic-atomic chip magnetometer based on alkali vapor with a micrometer-scale spatial resolution and a magnetic sensitivity of 700 pT/√Hz. The presented platform paves the way for future applications using integrated photonic–atomic chips, including high-spatial-resolution magnetometry, near-field vectorial imaging, magnetically induced switching, and optical isolation.

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