Long-range surface plasmon resonance and its sensing applications: A review

Tunable and high-sensitivity sensing based on Fano resonance is analytically and numerically investigated in coupled plasmonic cavities structure. To analyze and manipulate the Fano line shape, the coupled cavities are taken as a composite cavity that supports at least two resonance modes. A theoretical model is newly-established, and its results agree well with the finite difference time domain (FDTD) simulations for the plasmonic stub-pair structure. The detection sensitivity factor in coupled cavities approaches 6.541 × 107 m-1, which is an order of magnitude larger than single stub case. In addition, the wavelengths of resonant modes in the plasmonic stub-pair structure can be adjusted independently, which paves a new way for improving detection sensitivity. These discoveries hold potential applications for realizing tunable and highly integrated photonic devices.

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Tunable and high-sensitivity sensing based on Fano resonance with coupled plasmonic cavities

In this paper, an asymmetric plasmonic structure composed of two MIM (metal-insulator-metal) waveguides and two rectangular cavities is reported, which can support triple Fano resonances originating from three different mechanisms. And the multimode interference coupled mode theory (MICMT) including coupling phases is proposed based on single mode coupled mode theory (CMT), which is used for describing and explaining the multiple Fano resonance phenomenon in coupled plasmonic resonator systems. Just because the triple Fano resonances originate from three different mechanisms, each Fano resonance can be tuned independently or semi-independently by changing the parameters of the two rectangular cavities. Such, a narrow 'M' type of double Lorentzian-like line-shape transmission windows with the position and the full width at half maximum (FWHM) can be tuned freely is constructed by changing the parameters of the two cavities appropriately, which can find widely applications in sensors, nonlinear and slow-light devices.

Tunable triple Fano resonances based on multimode interference in coupled plasmonic resonator system

External temperature variations inevitably affect the accuracy of surface plasmon resonance (SPR) biosensors To that end, we propose an ultra-compact label-free dual-channel SPR fiber sensor (DSPRFS) that can simultaneously measure the glucose concentration and ambient temperature in real-time The proposed sensor is based on a unique dual-channel structure fabricated by etching a side-hole fiber (SHF), and has significantly higher spatial sensitivity than traditional SPR biosensors After coating with silver and zinc oxide films, one channel was filled with polydimethylsiloxane (PDMS) to sense the ambient temperature, and the other channel was immobilized with glucose oxidase (GOx) enzyme for glucose sensing The proposed sensor is analyzed theoretically, fabricated and characterized Glucose concentration sensitivity and temperature sensitivity of the manufactured sensor sample were found to be as high as 6156 nm/mMand -1604 nm/°C with limits of detection (LOD) of 1624 µM and 006 °C, respectively The proposed sensor has an extremely compact structure, enables temperature compensation, and is suitable for in-situ monitoring and high-precision sensing of glucose and other biological analytes

In-situ dual-channel surface plasmon resonance fiber sensor for temperature-compensated detection of glucose concentration

Ultra-fast all-optical plasmonic switching in near infra-red spectrum using a Kerr nonlinear ring resonator

Metallic film thickness optimization in mono- and bimetallic plasmonic structures has been carried out in order to determine the correct device parameters. Different resonance parameters, such as reflectivity, phase, field enhancement, and the complex amplitude reflectance Argand diagram (CARAD), have been investigated for the proposed optimization procedure. Comparison of mono- and bimetallic plasmonic structures has been carried out in the context of these resonance parameters with simultaneous angular and spectral interrogation. Differential phase analysis has also been performed and its application to sensing has been discussed along with a proposed interferometric set-up.

Resonance parameters based analysis for metallic thickness optimization of a bimetallic plasmonic structure

A new scheme of variable thickness ladder-like stepped metal film for simultaneous excitation of surface plasmon resonance (SPR) with different wavelength based on modified three layer Kretschmann configuration has been proposed. Metal thickness has been optimized for four different wavelengths ranging from visible to near infrared. The thickness has also been optimized for different substrates as well as different metal films in order to show the dependency of the substrate and metal layers on the ultimate performance of the plasmonic structure. A new concept of Reflectance Constrained Dynamic Range has been employed and its value has been calculated numerically and graphically for each SPR structure under consideration and for each wavelength considering water as reference sample and using the optimized metal thickness. Electric field enhancement has been evaluated for different structures and the full width half maximum has also been calculated for four working wavelengths in order to study the field confinement and measurement accuracy. Longer wavelength provides larger dynamic range and better measurement precision, which is desirable for biochemical sensing. Moreover, this multi-channel ladder-like stepped metallic structure can also be utilized for simultaneous sensing of different samples.

Simultaneous excitation of multi-spectral surface plasmon resonance using multi-stepped-thickness metallic film

In view of the increasing need for detection and analysis of chemical and biochemical substances in many important areas including medicine, environmental monitoring, biotechnology, drug and food monitoring, surface plasmon resonance (SPR) sensor technology holds a significant potential. An intermediate dielectric layer may be introduced between the glass prism and the thin metallic film to have a better precision in chemical sensors. In this paper we have studied and simulated various SPR curves in MATLAB environment, which further helps to determine certain optical properties, such as refractive index and thickness of homogeneous thin transparent films. Based on the proposed application of SPR to the sensor technology, our simulation results throw some insight into the sensitivity of detection and signature of various chemical/biological samples. In order to increase the precision, some supplementary procedural techniques have also been proposed to compensate for the minor errors during the measurement of a particular sensing parameter used in the SPR based bio/chemical sensor.

Precise detection and signature of biological/chemical samples based on surface plasmon resonance (SPR)

Experimental investigation on surface plasmon resonance (SPR) modulated interference has been proposed and demonstrated under radially sheared environment with the help of a birefringent lens. SPR modulated interference images captured by a charged couple device have been demonstrated in two different analyzing regime, namely, using an analyzer and using a Wollaston prism, the later being advantageous for the simultaneous observation of p- and s-polarized contribution towards SPR. We also report the analysis of the interference imaging for the two substrate materials and also for the two analytes in order to show the substrate-sample dependency of SPR. Moreover, phase dependent resonant behavior, together with the analysis of amplitude reflection co-efficient in complex plane, has been theoretically simulated and discussed in support of the present experimental investigation, which can be well utilized for biological and chemical sensing.

Experimental surface plasmon resonance modulated radially sheared interference imaging using a birefringent lens

Numerical investigations of metal–dielectric–metal waveguide-coupled dual nanoresonator is demonstrated. Phase dependent resonant behavior along with its complex plane analysis is investigated in wavelength regime. Detailed analysis of the influence of the structural parameters on the resonance curve helps to determine the correct device parameters for different plasmonic applications. This waveguide-coupled plasmonic resonator can be utilized for chemical and biological sensing. In this context, figure of merit related to the asymmetric Fano line shape is redefined, incorporating both differential phase and quality (Q)-factor. Theoretical analysis of differential phase sensitivity in wavelength regime predicts the possibility of detection of refractive index change of the order of 10 −8 RIU.

Mahua Bera

Papers

Resonance parameters based analysis for metallic thickness optimization of a bimetallic plasmonic structure

Simultaneous excitation of multi-spectral surface plasmon resonance using multi-stepped-thickness metallic film

Precise detection and signature of biological/chemical samples based on surface plasmon resonance (SPR)

Experimental surface plasmon resonance modulated radially sheared interference imaging using a birefringent lens

Parametric Analysis of Spectral Fano Lineshape for Plasmonic Waveguide-Coupled Dual Nanoresonator