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1

Design of localized surface plasmon resonance-based refractive index sensor using optical fiber

Yadav Mukti, Kaler R. S.

Optica Applicata

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2024

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Vol. 54, nr 1

85--96

EN

The paper proposes a design of a localized surface plasmon resonance-based refractive index sensor for the detection of a chemical compound availing unclad geometry of the optical fiber. The geometry is explored to analyze the sensing behavior and coupling phenomenon at the metal-dielectric interface. The finite element method (FEM) is applied numerically to evaluate the analytical change in the reflectance spectra of the fiber model by inoculating potassium nitrate compound. The resonance shift and reflectance of the surface plasmon resonance (SPR) signal obtained after the optimization of structural parameters enhance the sensing performance of the prototype. The sensor exhibits a maximum sensitivity of 80.2919 rad/RIU for a 1.56 high refractive index analyte and minimum sensitivity of 2.3446 rad/RIU for a 1.33 low refractive index analyte. The proposed sensor is modelled in such a way that it can be employed in various sensing applications for a wide range of refractive indices.

2

Optical simulations and optimization of highly sensitive biosensor for cancer cell detection

El Mouncharih Abdelkarim, Takassa Rabi, Farkad Omar, Tchenka Abdelaziz, Ibnouelghazi El Alami, Abouelaoualim Driss

Optica Applicata

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2023

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Vol. 53, nr 3

407--418

EN

In this work, using the two-dimensional finite difference time domain method, we are theoretically studying the optical properties of a two-dimensional photonic crystal biosensor based on silicon rods arranged as a square structure in an air bottom with two waveguides and a nanocavity. For this purpose, six different cells are infiltrated into the point defect. These six cells are Jurkat, HeLa, PC-12, MDA-MB-231, MCF-7, and basal cells. As a result, we have successfully detected cancer and benign cases of these cells through resonance peaks in the transmission spectrum. We evaluated the sensitivity, quality factor, detection limit, and figure of merit at different values for sensing region radius for optimization purposes. We report that we observed the maximum sensitivity of 1350 nm/RIU at 0.15 μm for the basal cell. Finally, the proposed biosensor can be a miniaturized structure with extreme sensitivity in cancer cell detection models.

3

Nanoblocks embedded in L-shaped nanocavity of a plasmonic sensor for best sensor performance

Butt M. A., Kazanskiy N. L.

Optica Applicata

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2021

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Vol. 51, nr 1

109--120

EN

In this work, we proposed a highly sensitive design of a plasmonic sensor which is formed by embedding a periodic array of nanoblocks in L-shaped cavity formed by the metal–insulator–metal waveguide. The nanoblocks are placed in the strong electric field confinement region to further enhance its strength by confining it to a small area. To validate the study, the spectral characteristics of the proposed sensor design is compared to the spectral characteristics of a standard design having the same geometric parameters excluding nanoblocks in the cavity. The study shows that the incorporation of 5 nanoblocks of length 25 nm in the cavity can provide best performance indicators in the form of sensitivity, figure of merit and Q-factor. The sensitivity, figure of merit and Q-factor of the proposed sensor design is 1065 nm/RIU, 251.17 and 343.4 which is significantly higher than the standard L-shape resonator design. The sensor design can be developed with a single fabrication step. Due to the ease of fabrication and the highly responsive nature of the design, it can be used in biomedical applications.

4

Single air-mode resonance photonic crystal nanofiber cavity for ultra-high sensitivity refractive index sensing

Zhang Yanni, Yang Jiaxi, Song Meiqi, Zhang Xuan, Yang Daquan

Optica Applicata

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2020

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Vol. 50, nr 2

199--207

EN

We propose a design of series-connected one-dimensional photonic crystal nanofiber cavity sensor (1-D PC-NCS) and one-dimensional photonic crystal nanofiber bandgap filter (1-D PC-NBF). The proposed structure can get a single air mode for refractive index sensing with its extinction ratio of 58.64 dB. It filters out the high order mode and reduces the interaction between signals. By 3D FDTD, the calculated sensitivity is 848.18 nm/RIU (RIU – refractive index unit). Compared with general silicon on-chip nanobeam cavity, the sensitivity is increased by eight times. The additional 1-D PC-NBF will not change the sensitivity and the position of the resonance wavelength. Therefore, the new design we propose addresses the issue of crosstalk, and can be applied to ultra-high sensitivity index-based gas sensing and biosensing without the need for complicated coupling systems.

5

Nanoslotted microring resonator for high figure of merit refractive index sensing

Yang Daquan, Duan Bing, Zhang Xuan, Lu Hui

Optica Applicata

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2020

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Vol. 50, nr 1

37--47

EN

A nanoslotted microring resonator (NSMR) with enhanced light-matter interaction has been designed, which can be used for high sensitive refractive index sensing. The performance of the device is investigated theoretically based on a three-dimensional finite-difference time-domain (3D-FDTD) method. In order to achieve high figure of merit sensing, the nanoslot geometry is exploited to make the optical field strongly localized inside the low index region and overlap sufficiently with the analytes. By using the 3D-FDTD method, the proposed NSMR sensor device achieves a high Q-factor (Q > 105) and sensitivity ~100 nm/RIU (RIU – refractive index unit). Moreover, the strong light confinement introduced by the nanoslot in NSMR results in the sensor figure of merit as high as 6.73 × 103. Thus, the design we proposed is a promising platform for refractive index-based biochemical sensing and lab-on-a-chip applications.

6

Design of a highly sensitive photonic crystal refractive index sensor incorporating ring-shaped GaAs cavity

Rahman-Zadeh F., Danaie M., Kaatuzian H.

Opto-Electronics Review

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2019

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Vol. 27, No. 4

369--377

EN

Two highly sensitive optical sensor topologies are proposed and simulated in this paper. The proposed structures are optimized to provide better performance characteristics such as sensitivity, detection limit, and quality factor. They are based on two-dimensional photonic crystals consisting of rectangular arrays of GaAs rods in SiO2 substrates. Such lattices have bandgaps for transverse magnetic modes. Two-dimensional finite difference time domain and plane wave expansion methods are used for the simulation and analysis of the refractive index sensors and particle swarm optimization method is used to optimize the structural parameters. The designed structures show a high sensitivity to refractive index variations. They are able to detect refractive indices from 1.33 to 1.5. An excellent figure of merit equal to 737 RIU−1 is observed for the proposed structure and a significant improvement is observed compared to the structures reported in the literature.