scholarly journals Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3247
Author(s):  
Lina Grineviciute ◽  
Soon Hock Ng ◽  
Molong Han ◽  
Tania Moein ◽  
Vijayakumar Anand ◽  
...  
Keyword(s):  
Angular Dependence ◽  
Field Enhancement ◽  
Absorption Bands ◽  
Mid Infrared ◽  
Infrared Microspectroscopy ◽  
Enhanced Absorption ◽  
Glancing Angle ◽  
Infrared Spectral ◽  
Stretching Vibration ◽  
Polarisation Analysis

Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

scholarly journals Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

2021 ◽  
Author(s):  
Lina Grineviciute ◽  
Soon Hock Ng ◽  
Molong Han ◽  
Tania Moein ◽  
Vijayakumar Anand ◽  
...  
Keyword(s):  
Angular Dependence ◽  
Field Enhancement ◽  
Absorption Bands ◽  
Mid Infrared ◽  
Infrared Microspectroscopy ◽  
Enhanced Absorption ◽  
Glancing Angle ◽  
Infrared Spectral ◽  
Stretching Vibration ◽  
Polarisation Analysis

Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

scholarly journals Lattice Rayleigh Anomaly Associated Enhancement of NH and CH Stretching Modes on Gold Metasurfaces for Overtone Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1265 ◽  
Author(s):  
Daler R. Dadadzhanov ◽  
Tigran A. Vartanyan ◽  
Alina Karabchevsky
Keyword(s):  
Near Infrared ◽  
Field Enhancement ◽  
Dielectric Substrate ◽  
Square Lattice ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Bands ◽  
Transparent Dielectric ◽  
Infrared Spectral ◽  
Rayleigh Anomaly

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element method (FEM), gold metasurfaces on a transparent dielectric substrate covered by weakly absorbing analyte supporting N-H and C-H overtone absorption bands around 1.5 μ m and around 1.67 μ m, respectively. We found that the absorption enhancement in N-H overtone transition can be increased up to the factor of 22.5 due to the combination of localized surface plasmon resonance in prolonged nanoparticles and lattice Rayleigh anomaly. Our approach may be extended for sensitive identification of other functional group overtone transitions in the near-infrared spectral range.

scholarly journals Enhanced Absorption with Graphene-Coated Silicon Carbide Nanowires for Mid-Infrared Nanophotonics

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2339
Author(s):  
Patrick Rufangura ◽  
Iryna Khodasevych ◽  
Arti Agrawal ◽  
Matteo Bosi ◽  
Thomas G. Folland ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Spectral Range ◽  
Field Enhancement ◽  
Experimental Methods ◽  
Hybrid Nanostructure ◽  
Mid Infrared ◽  
Enhanced Absorption ◽  
The Core ◽  
Coupling Medium ◽  
Plasmon Polaritons

The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide layer a few nanometers thick, sandwiched between the graphene and silicon carbide. This intermediate shell layer is characteristically obtained using our graphitization approach and acts as a coupling medium between the core and outer shell of the nanowires.

FR-IR Molecular Microanalysis System

1990 ◽  
Vol 48 (2) ◽  
pp. 270-271
Author(s):  
John A. Reffner ◽  
William T. Wihlborg
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Integrated System ◽  
Morphological Examination ◽  
Fully Integrated ◽  
Ir Microscopy ◽  
Normal Functions ◽  
Infrared Microspectroscopy ◽  
Infrared Spectral ◽  
Ft Ir

The IRμs™ is the first fully integrated system for Fourier transform infrared (FT-IR) microscopy. FT-IR microscopy combines light microscopy for morphological examination with infrared spectroscopy for chemical identification of microscopic samples or domains. Because the IRμs system is a new tool for molecular microanalysis, its optical, mechanical and system design are described to illustrate the state of development of molecular microanalysis. Applications of infrared microspectroscopy are reviewed by Messerschmidt and Harthcock.Infrared spectral analysis of microscopic samples is not a new idea, it dates back to 1949, with the first commercial instrument being offered by Perkin-Elmer Co. Inc. in 1953. These early efforts showed promise but failed the test of practically. It was not until the advances in computer science were applied did infrared microspectroscopy emerge as a useful technique. Microscopes designed as accessories for Fourier transform infrared spectrometers have been commercially available since 1983. These accessory microscopes provide the best means for analytical spectroscopists to analyze microscopic samples, while not interfering with the FT-IR spectrometer’s normal functions.

scholarly journals Group delay dispersion measurements in the mid-infrared spectral range of 2-20 µm

2016 ◽  
Vol 24 (15) ◽  
pp. 16705 ◽  
Author(s):  
Florian Habel ◽  
Michael Trubetskov ◽  
Vladimir Pervak
Keyword(s):  
Spectral Range ◽  
Group Delay ◽  
Group Delay Dispersion ◽  
Mid Infrared ◽  
Infrared Spectral Range ◽  
Infrared Spectral

scholarly journals Cavity enhanced absorption spectroscopy in the mid-infrared using a supercontinuum source

2017 ◽  
Vol 111 (6) ◽  
pp. 061103 ◽  
Author(s):  
Caroline Amiot ◽  
Antti Aalto ◽  
Piotr Ryczkowski ◽  
Juha Toivonen ◽  
Goëry Genty
Keyword(s):  
Absorption Spectroscopy ◽  
Mid Infrared ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy

scholarly journals Plasmon-Enhanced Photoresponse of Self-Powered Si Nanoholes Photodetector by Metal Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2460
Author(s):  
Pericle Varasteanu ◽  
Antonio Radoi ◽  
Oana Tutunaru ◽  
Anton Ficai ◽  
Razvan Pascu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Simulation Analysis ◽  
Field Enhancement ◽  
Metal Nanowires ◽  
Local Surface Plasmon Resonance ◽  
Resonance Effects ◽  
Enhanced Sensitivity ◽  
Infrared Spectral ◽  
Self Powered ◽  
Cost Efficient

In this work, we report the development of self-powered photodetectors that integrate silicon nanoholes (SiNHs) and four different types of metal nanowires (AgNWs, AuNWs, NiNWs, PtNWs) applied on the SiNHs’ surface using the solution processing method. The effectiveness of the proposed architectures is evidenced through extensive experimental and simulation analysis. The AgNWs/SiNHs device showed the highest photo-to-dark current ratio of 2.1 × 10−4, responsivity of 30 mA/W and detectivity of 2 × 1011 Jones along with the lowest noise equivalent power (NEP) parameter of 2.4 × 10−12 WHz−1/2 in the blue light region. Compared to the bare SiNHs device, the AuNWs/SiNHs device had significantly enhanced responsivity up to 15 mA/W, especially in the red and near-infrared spectral region. Intensity-modulated photovoltage spectroscopy (IMVS) measurements revealed that the AgNWs/SiNHs device generated the longest charge carrier lifetime at 470 nm, whereas the AuNWs/SiNHs showed the slowest recombination rate at 627 nm. Furthermore, numerical simulation confirmed the local field enhancement effects at the MeNWs and SiNHs interface. The study demonstrates a cost-efficient and scalable strategy to combine the superior light harvesting properties of SiNHs with the plasmonic absorption of metallic nanowires (MeNWs) towards enhanced sensitivity and spectral-selective photodetection induced by the local surface plasmon resonance effects.

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