Photonic resonator interferometric scattering microscopy

AbstractInterferometric scattering microscopy is increasingly employed in biomedical research owing to its extraordinary capability of detecting nano-objects individually through their intrinsic elastic scattering. To significantly improve the signal-to-noise ratio without increasing illumination intensity, we developed photonic resonator interferometric scattering microscopy (PRISM) in which a dielectric photonic crystal (PC) resonator is utilized as the sample substrate. The scattered light is amplified by the PC through resonant near-field enhancement, which then interferes with the <1% transmitted light to create a large intensity contrast. Importantly, the scattered photons assume the wavevectors delineated by PC’s photonic band structure, resulting in the ability to utilize a non-immersion objective without significant loss at illumination density as low as 25 W cm−2. An analytical model of the scattering process is discussed, followed by demonstration of virus and protein detection. The results showcase the promise of nanophotonic surfaces in the development of resonance-enhanced interferometric microscopies.

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Simulation of Electromagnetic Field Distribution at a Nanowire Probe for Near Field Scanning Optical Microscopy

ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer, Parts A and B ◽

10.1115/mnht2008-52078 ◽

2008 ◽

Author(s):

Nathan P. Malcolm ◽

Alex J. Heltzel ◽

Li Shi ◽

John R. Howell

Keyword(s):

Optical Microscopy ◽

Signal To Noise Ratio ◽

Near Field ◽

Three Dimensional ◽

Field Enhancement ◽

Fdtd Simulation ◽

Plasmonic Nanoparticle ◽

Excitation Laser ◽

Scanning Optical Microscopy ◽

Near Field Scanning

This work studies a new design of a near field scanning optical microscopy (NSOM) probe based on a ZnO nanowire sub-wavelength waveguide terminated with a plasmonic gold nanoparticle. Three-dimensional finite difference time domain (FDTD) simulation is used to visualize light guiding in the nanowire and near field coupling between the plasmonic nanoparticle and the substrate. The simulation results reveal local field enhancement at the gap between the nanoparticle and a gold substrate when the nanowire axis is tilted from the substrate normal by a small angle. The enhancement occurs only along the cross section plane that is parallel to the polarization of the excitation laser beam. The regime of field enhancement is much smaller than the diameter of the 100 nm plasmonic particle, making the nanowire probe well suited for NSOM with superior spatial resolution and signal to noise ratio compared to the state of the art.

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A Time-Resolved Low-Angle Light Scattering Apparatus. Application to Phase Separation Problems in Polymer Systems

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20010973 ◽

2001 ◽

Vol 66 (6) ◽

pp. 973-982 ◽

Cited By ~ 5

Author(s):

Čestmír Koňák ◽

Jaroslav Holoubek ◽

Petr Štěpánek

Keyword(s):

Phase Separation ◽

Light Scattering ◽

Signal To Noise Ratio ◽

Scattered Light ◽

Ccd Camera ◽

Time Resolved ◽

Polymer Systems ◽

Software Analysis ◽

Phase Separation Kinetics ◽

Small Angle Light Scattering

A time-resolved small-angle light scattering apparatus equipped with azimuthal integration by means of a conical lens or software analysis of scattering patterns detected with a CCD camera was developed. Averaging allows a significant reduction of the signal-to-noise ratio of scattered light and makes this technique suitable for investigation of phase separation kinetics. Examples of applications to time evolution of phase separation in concentrated statistical copolymer solutions and dissolution of phase-separated domains in polymer blends are given.

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Effects of gap thickness and emitter location on the photoluminescence enhancement of monolayer MoS2 in a plasmonic nanoparticle-film coupled system

Nanophotonics ◽

10.1515/nanoph-2020-0178 ◽

2020 ◽

Vol 9 (7) ◽

pp. 2097-2105

Author(s):

Xiaozhuo Qi ◽

Tsz Wing Lo ◽

Di Liu ◽

Lantian Feng ◽

Yang Chen ◽

...

Keyword(s):

Near Field ◽

Central Area ◽

Field Enhancement ◽

Coupled System ◽

Film Structure ◽

Plasmonic Nanoparticle ◽

Emitter Location ◽

Radiation Properties ◽

Radiation Enhancement ◽

Quantum Emitters

AbstractPlasmonic nanocavities comprised of metal film-coupled nanoparticles have emerged as a versatile nanophotonic platform benefiting from their ultrasmall mode volume and large Purcell factors. In the weak-coupling regime, the particle-film gap thickness affects the photoluminescence (PL) of quantum emitters sandwiched therein. Here, we investigated the Purcell effect-enhanced PL of monolayer MoS2 inserted in the gap of a gold nanoparticle (AuNP)–alumina (Al2O3)–gold film (Au Film) structure. Under confocal illumination by a 532 nm CW laser, we observed a 7-fold PL peak intensity enhancement for the cavity-sandwiched MoS2 at an optimal Al2O3 thickness of 5 nm, corresponding to a local PL enhancement of ∼350 by normalizing the actual illumination area to the cavity’s effective near-field enhancement area. Full-wave simulations reveal a counterintuitive fact that radiation enhancement comes from the non-central area of the cavity rather than the cavity center. By scanning an electric dipole across the nanocavity, we obtained an average radiation enhancement factor of about 65 for an Al2O3 spacer thickness of 4 nm, agreeing well with the experimental thickness and indicating further PL enhancement optimization. Our results indicate the importance of configuration optimization, emitter location and excitation condition when using such plasmonic nanocavities to modulate the radiation properties of quantum emitters.

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Ultrasonic Imaging of Thick Carbon Fiber Reinforced Polymers through Pulse-Compression-Based Phased Array

Applied Sciences ◽

10.3390/app11041508 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1508

Author(s):

Muhammad Khalid Rizwan ◽

Stefano Laureti ◽

Hubert Mooshofer ◽

Matthias Goldammer ◽

Marco Ricci

Keyword(s):

Carbon Fiber ◽

Pulse Compression ◽

Phased Array ◽

Signal To Noise Ratio ◽

Near Field ◽

Ultrasonic Imaging ◽

Fiber Reinforced Polymers ◽

Fiber Reinforced ◽

Custom Made ◽

Carbon Fiber Reinforced

The use of pulse-compression in ultrasonic non-destructive testing has assured, in various applications, a significant improvement in the signal-to-noise ratio. In this work, the technique is combined with linear phased array to improve the sensitivity and resolution in the ultrasonic imaging of highly attenuating and scattering materials. A series of tests were conducted on a 60 mm thick carbon fiber reinforced polymer benchmark sample with known defects using a custom-made pulse-compression-based phased array system. Sector scan and total focusing method images of the sample were obtained with the developed system and were compared with those reconstructed by using a commercial pulse-echo phased array system. While an almost identical sensitivity was found in the near field, the pulse-compression-based system surpassed the standard one in the far-field producing a more accurate imaging of the deepest defects and of the backwall of the sample.

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