scholarly journals Analysis of Scaling Law and Figure of Merit of Fiber-Based Biosensor

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jui-Teng Lin ◽  
Da-Chuan Cheng ◽  
Minshan Jiang ◽  
Yueh-Sheng Chiang ◽  
Hsia-Wei Liu
Keyword(s):  
Refractive Index ◽  
Aspect Ratio ◽  
Figure Of Merit ◽  
Scaling Laws ◽  
Scaling Law ◽  
Optimal Designs ◽  
Plasmon Excitation ◽  
Refractive Index Sensitivity ◽  
Optimal Value ◽  
Index Sensitivity

This paper presents a normalized transmitted signal (NTS) of a fiber-based sensor using gold nanorods as the plasmon excitation medium of the evanescent wave. The NTS and the refractive index (RI) sensitivity is calculated as a function of the gold aspect ratio (R), the RI of the sensing medium, and a scaling parameter given by the ratio of the fiber length and its diameter. Finally, the optimal value of gold aspect ratio is calculated to beR= (3.0–4.0) for maximum figure of merits (FOMs) defined by the ratio of the refractive index sensitivity and the full width at half maximum. The scaling laws and the FOM presented in this paper may serve as the guidelines for optimal designs in fiber-based nanosensors.

scholarly journals Refractive index sensing with Fano resonances in silicon oligomers

2017 ◽  
Vol 375 (2090) ◽  
pp. 20160070 ◽  
Author(s):  
Katie E. Chong ◽  
Henry W. Orton ◽  
Isabelle Staude ◽  
Manuel Decker ◽  
Andrey E. Miroshnichenko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Figure Of Merit ◽  
Spectral Features ◽  
Fano Resonances ◽  
Refractive Index Sensitivity ◽  
New Horizons ◽  
Refractive Index Sensing ◽  
Index Sensitivity

We demonstrate experimentally refractive index sensing with localized Fano resonances in silicon oligomers, consisting of six disks surrounding a central one of slightly different diameter. Owing to the low absorption and narrow Fano-resonant spectral features appearing as a result of the interference of the modes of the outer and the central disks, we demonstrate refractive index sensitivity of more than 150 nm RIU −1 with a figure of merit of 3.8. This article is part of the themed issue ‘New horizons for nanophotonics’.

scholarly journals Tunable Fano Resonances in an Ultra-Small Gap

2020 ◽  
Vol 10 (7) ◽  
pp. 2603
Author(s):  
Fuqiang Yao ◽  
Fang Li ◽  
Zhicong He ◽  
Yahui Liu ◽  
Litu Xu ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Performance ◽  
Figure Of Merit ◽  
Silver Film ◽  
Destructive Interference ◽  
Refractive Index Sensitivity ◽  
Thin Aluminum ◽  
Index Sensitivity ◽  
Index Unit ◽  
Dielectric Environment

A Fano resonance is experimentally observed in a single silver nanocube separated from a supporting silver film by a thin aluminum oxide film. The resonance spectrum is modulated by changing the size of the silver nanocube and its distance from the silver film. The system is fabricated by a bottom-up process with an accurately controlled nanogap at the sub-6-nm scale. The simulation result shows that the destructive interference between the dipole mode and the quadrupole mode in this “nanocube on mirror” (NCoM) structure is responsible for the resonance. The spectra red-shifted as the size of the silver nanocube increased and its distance from the silver film decreased. In addition, a refractive index sensitivity of the spectrum of 140 meV/RIU (refractive index unit), with a 2.4 figure of merit, is obtained by changing the dielectric environment around the silver nanocube. This work will enable the development of high-performance tunable optical nanodevices based on NCoM structures.

scholarly journals Improved Refractive Index Sensitivity Utilizing Long-Period Gratings with Periodic Corrugations on Cladding

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Anthony Lim ◽  
Wen Bin Ji ◽  
Swee Chuan Tjin
Keyword(s):  
Refractive Index ◽  
Cost Effective ◽  
Experimental Results ◽  
Refractive Index Sensitivity ◽  
Long Period ◽  
Specimen Collection ◽  
Long Period Gratings ◽  
Highly Sensitive ◽  
Index Sensitivity

A new structure of Long-Period Gratings (LPGs) sensor is introduced as a sensitive ambient RI sensor. This structure consists of creating periodic corrugations on the cladding of the LPG. The experimental results show that this LPG structure has good performances in terms of linearity and sensitivity and serves as a highly sensitive and cost-effective sensor. It also has the advantage of portability as the corrugation can also serve as the reservoir for the specimen collection to be tested.

scholarly journals Enhanced Plasmonic Resonance Characteristics of AgNRs–Gold Film Hybrid System

2021 ◽  
Vol 8 ◽  
Author(s):  
Yanping Yin ◽  
Jin Zhu ◽  
Zaoji Wang ◽  
Guojun Ma ◽  
Huining Yuan ◽  
...  
Keyword(s):  
Refractive Index ◽  
Aspect Ratio ◽  
Gold Film ◽  
Spectral Response ◽  
Surrounding Medium ◽  
Resonance Wavelength ◽  
Spectral Shift ◽  
Refractive Index Sensor ◽  
Gap Size ◽  
Refractive Index Sensitivity

In recent years, the plasma gap resonance maintained by metal-film-coupled nanostructures has attracted extensive attention. This mainly originates from its flexible control of the spectral response and significantly enhanced field strength at the nanoparticle–film junction. In the present study, the tunability of local surface plasmon resonances (LSPRs) of nanorods coupled to a gold film is studied theoretically. To this end, the plasmonic resonances in the nanostructure of individual silver nanorod–gold film (AgNR-film) with different parameters are investigated. Obtained results show that the refractive index sensitivity (S) of nanostructures to the environment increases as the aspect ratio (Ar) of nanostructures increase. It is found that when the aspect ratio (Ar) is set to 3.5, the figure of merit (FOM) is the highest. Moreover, the variation in the gap distances of the nanorod monomer–gold film, electric field distribution of nanorods dimer, and the corresponding impact on the gold film are studied. It is concluded that the gap size of nanostructures has an exponential correlation with the resonance wavelength. Considering the remarkable influence of the gap size and the surrounding medium environment on the spectral shift of AgNR-film nanostructures, potential applications of the structure as a refractive index sensor and biomolecule measurement are proposed.

scholarly journals Improve the Hole Size-dependent Refractive Index Sensitivity  of Au-Ag Nanocages by Tuning the Alloy Composition

2021 ◽  
Author(s):  
Jianjun LI ◽  
Qiu-Xiang Qin ◽  
Guo-Jun Weng ◽  
Jian Zhu ◽  
Jun-Wu Zhao
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Electric Field ◽  
Alloy Composition ◽  
Geometric Parameters ◽  
Sensitivity Factor ◽  
Hole Size ◽  
Refractive Index Sensitivity ◽  
Electric Field Direction ◽  
Index Sensitivity

Abstract In this study, the nanoboxes is converted into Au-Ag alloy nanocages by increasing the hole size. Discrete dipole approximation (DDA) is used to study the extinction spectrum and the refractive index sensing characteristics of Au-Ag alloy nanocages with different geometric parameters. With the increase of Au component, the local surface plasmon resonance (LSPR) peak shows approximately linear redshift and the sensitivity factor shows approximately linear decrease. The refractive index sensitivity can be effectively controlled by the Au-Ag ratio at large hole size because the hole and cavity surfaces distribute more environmental dielectric components. Therefore, increasing the hole size and decreasing the Au-Ag ratio can improve the refractive index sensitivity. To explain the effect of alloy composition on the LSPR characteristics and the refractive index sensitivity, the local electric field distributions with different geometric parameters are plotted. We find that the electric field direction on the hole and cavity surfaces are controlled by the Au-Ag ratio and environmental dielectric constant. Moreover, the field vector on the hole and cavity surfaces are formed by the superposition of the incident field, the electric field generated by the oscillating electrons on the outer surface, and the polarized field in the environmental dielectric constant.

Influence of diamond-like carbon overlay properties on refractive index sensitivity of nano-coated optical fibres

2013 ◽  
Vol 210 (10) ◽  
pp. 2100-2105 ◽  
Author(s):  
Mateusz Śmietana ◽  
Mariusz Dudek ◽  
Marcin Koba ◽  
Bartosz Michalak
Keyword(s):  
Refractive Index ◽  
Diamond Like Carbon ◽  
Optical Fibres ◽  
Refractive Index Sensitivity ◽  
Index Sensitivity

Measurements of refractive index sensitivity using long-period grating refractometer

2004 ◽  
Vol 229 (1-6) ◽  
pp. 65-69 ◽  
Author(s):  
Joo Hin Chong ◽  
Ping Shum ◽  
H Haryono ◽  
A Yohana ◽  
M.K Rao ◽  
...  
Keyword(s):  
Refractive Index ◽  
Long Period Grating ◽  
Refractive Index Sensitivity ◽  
Long Period ◽  
Index Sensitivity
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