Wide range refractive index sensor based on a coupled structure of Au nanocubes and Au film

In the present paper, a new kind of concave shaped refractive index sensor (CSRIS) exploiting localized surface plasmon resonance (LSPR) is proposed and numerically optimized. The LSPR effect between polaritons and the core guided mode of designed CSRIS is used to enhance the sensing performance. The sensor is characterized for two types of sensing structures coated with gold (Au) film and Au nanowires (AuNWs), respectively. The influence of structural parameters such as the distance (D) of the concave shaped channel (CSC) from the core, the diameter of the nanowire (dn) and the size (s) of the CSC are investigated here. In comparison to Au film, the AuNWs are shown to significantly enhance the sensitivity and the performance of the designed sensor. An enhanced sensitivity of 4471 nm/RIU (refractive index unit) is obtained with AuNWs, for a wide range of analytes refractive index (na) varying between 1.33 to 1.38. However, for conventional Au film; the sensitivity of 808.57 nm/RIU is obtained for the same range of analytes.

Download Full-text

Improved Refractive Index-Sensing Performance of Multimode Fano-Resonance-Based Metal-Insulator-Metal Nanostructures

Nanomaterials ◽

10.3390/nano11082097 ◽

2021 ◽

Vol 11 (8) ◽

pp. 2097

Author(s):

Yuan-Fong Chou Chau ◽

Chung-Ting Chou Chao ◽

Siti Zubaidah Binti Haji Jumat ◽

Muhammad Raziq Rahimi Kooh ◽

Roshan Thotagamuge ◽

...

Keyword(s):

Refractive Index ◽

Plasmon Resonance ◽

Fano Resonance ◽

High Sensitivity ◽

Metal Nanostructures ◽

Refractive Index Sensor ◽

Metal Insulator ◽

Wide Range ◽

Metal Insulator Metal ◽

Mode 2

This work proposed a multiple mode Fano resonance-based refractive index sensor with high sensitivity that is a rarely investigated structure. The designed device consists of a metal–insulator–metal (MIM) waveguide with two rectangular stubs side-coupled with an elliptical resonator embedded with an air path in the resonator and several metal defects set in the bus waveguide. We systematically studied three types of sensor structures employing the finite element method. Results show that the surface plasmon mode’s splitting is affected by the geometry of the sensor. We found that the transmittance dips and peaks can dramatically change by adding the dual air stubs, and the light–matter interaction can effectively enhance by embedding an air path in the resonator and the metal defects in the bus waveguide. The double air stubs and an air path contribute to the cavity plasmon resonance, and the metal defects facilitate the gap plasmon resonance in the proposed plasmonic sensor, resulting in remarkable characteristics compared with those of plasmonic sensors. The high sensitivity of 2600 nm/RIU and 1200 nm/RIU can simultaneously achieve in mode 1 and mode 2 of the proposed type 3 structure, which considerably raises the sensitivity by 216.67% for mode 1 and 133.33% for mode 2 compared to its regular counterpart, i.e., type 2 structure. The designed sensing structure can detect the material’s refractive index in a wide range of gas, liquids, and biomaterials (e.g., hemoglobin concentration).

Download Full-text

Wide Range Refractive Index Sensor Using a Birefringent Optical Fiber

10.21203/rs.3.rs-172462/v1 ◽

2021 ◽

Author(s):

Moutusi De ◽

Vinod Kumar Singh

Keyword(s):

Refractive Index ◽

Near Infrared ◽

High Sensitivity ◽

Infrared Region ◽

Device Fabrication ◽

Refractive Index Sensor ◽

Potential Candidate ◽

Wide Range ◽

Analyte Detection ◽

Birefringent Optical Fiber

Abstract In this article, an efficient high birefringent D-shaped photonic crystal fiber (HB-D-PCF) plasmonic refractive index sensor is reported. It is able to work over a long low refractive index (RI) analyte range from 1.29 to 1.36. This modified simple structured hexagonal PCF has high birefringence in the near-infrared region. A thin gold film protected by a titanium dioxide (TiO2) layer is deposited on the D-surface of the PCF which acts as surface plasmon active layer. The sensor consists of an analyte channel on the top of the fiber. The performance of the HB-D-PCF is analyzed based on finite element method (FEM). Both wavelength and amplitude interrogation techniques are applied to study the sensing performance of the optimized sensor. Numerical results show wavelength and amplitude sensitivity of 9245nm/RIU and 1312 RIU-1 respectively with high resolution. Owing to the high sensitivity, long range sensing ability as well as spectral stability the designed HB-D-PCF SPR sensor is a potential candidate for water pollution control, glucose concentration testing, biochemical analyte detection as well as portable device fabrication.

Download Full-text

A Tunable Plasmonic Refractive Index Sensor with Nanoring-Strip Graphene Arrays

Sensors ◽

10.3390/s18124489 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4489 ◽

Cited By ~ 32

Author(s):

Chunlian Cen ◽

Hang Lin ◽

Jing Huang ◽

Cuiping Liang ◽

Xifang Chen ◽

...

Keyword(s):

Refractive Index ◽

Doping Level ◽

Transverse Electric ◽

Resonance Wavelength ◽

Transverse Magnetic ◽

Refractive Index Sensor ◽

Transmission Characteristics ◽

Wide Range ◽

Strip Length ◽

Mode A

In the present study, we design a tunable plasmonic refractive index sensor with nanoring-strip graphene arrays. The calculations prove that the nanoring-strip have two transmission dips. By changing the strip length L of the present structure, we find that the nanoring-strip graphene arrays have a wide range of resonances (resonance wavelength increases from 17.73 μm to 28.15 μm). When changing the sensing medium refractive index nmed, the sensitivity of mode A and B can reach 2.97 μm/RIU and 5.20 μm/RIU. By changing the doping level ng, we notice that the transmission characteristics can be tuned flexibly. Finally, the proposed sensor also shows good angle tolerance for both transverse magnetic (TM) and transverse electric (TE) polarizations. The proposed nanoring-strip graphene arrays along with the numerical results could open a new avenue to realize various tunable plasmon devices and have a great application prospect in biosensing, detection, and imaging.

Download Full-text

A wide-range temperature immune refractive-index sensor using concatenated long-period-fiber-gratings

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2016.12.012 ◽

2017 ◽

Vol 243 ◽

pp. 1109-1114 ◽

Cited By ~ 11

Author(s):

Saurabh Mani Tripathi ◽

Wojtek J. Bock ◽

Predrag Mikulic

Keyword(s):

Refractive Index ◽

Refractive Index Sensor ◽

Fiber Gratings ◽

Long Period ◽

Wide Range ◽

Long Period Fiber Gratings

Download Full-text

Solution refractive index sensor with wide-range high-resolution linear response based on short no-core fiber

Acta Physica Sinica ◽

10.7498/aps.62.150703 ◽

2013 ◽

Vol 62 (15) ◽

pp. 150703

Author(s):

Zheng Jing-Jing ◽

Jian Shui-Sheng ◽

Ma Lin ◽

Bai Yun-Long ◽

Pei Li ◽

...

Keyword(s):

Refractive Index ◽

High Resolution ◽

Linear Response ◽

Refractive Index Sensor ◽

Wide Range ◽

Core Fiber

Download Full-text

Refractive Index Sensor Based on Metal-Clad Planar Polymer Waveguide Operating at 850 nm

Photonic Sensors ◽

10.1007/s13320-020-0606-1 ◽

2020 ◽

Author(s):

Lanting Ji ◽

Wei Wei ◽

Gang Li ◽

Shuqing Yang ◽

Yujie Fu ◽

...

Keyword(s):

Refractive Index ◽

Buffer Layer ◽

Layer Thickness ◽

Low Cost ◽

Water Environment ◽

Polymer Materials ◽

Refractive Index Sensor ◽

Polymer Waveguide ◽

Waveguide Width ◽

Wide Range

Abstract A metal-clad planar polymer waveguide refractive index sensor based on epoxy (EPO) polymer materials by using light intensity interrogation at 850 nm is designed. The polymethyl methacrylate (PMMA) material is deployed as the low refractive index (RI) buffer layer in order to better couple the optical guided mode and the surface plasmon polaritons (SPP) mode for working in water environment. The effects of the gold film thickness, PMMA buffer layer thickness, waveguide layer thickness, waveguide width, and gold length on the sensor sensing characteristics have been comprehensively studied. Simulation results demonstrate that the normalized transmission increases quasi-linearly with the increment of RI of the analyte from 1.33 to 1.46. The sensitivity is 491.5 dB/RIU, corresponding to a high RI resolution of 2.6×10−9 RIU. The designed SPP-based optical waveguide sensor is low-cost, wide-range, and high-precision, and has a broad application prospect in biochemical sensing with merits of miniaturization, flexibility, and multiplexing.

Download Full-text

Fiber Reshaping-Based Refractive Index Sensor Interrogated through Both Intensity and Wavelength Detection

Sensors ◽

10.3390/s19112477 ◽

2019 ◽

Vol 19 (11) ◽

pp. 2477

Author(s):

Peng Ji ◽

Shiru Jiang ◽

Sang-Shin Lee

Keyword(s):

Refractive Index ◽

Intensity Variation ◽

Intensity Difference ◽

Wavelength Shift ◽

Refractive Index Sensor ◽

Interaction Length ◽

Surrounding Environment ◽

Wide Range ◽

Mmi Coupler ◽

Wavelength Detection

A fiber reshaping-based refractive index (RI) sensor is proposed relying on both optical intensity variation and wavelength shift. The objective of this study is to completely reshape the core and to ultimately mimic a coreless fiber, thereby creating a highly efficient multimode interference (MMI) coupler. Thus, propagation modes are permitted to leak out into the cladding and eventually escape out of the fiber, depending on the surrounding environment. Two interrogation mechanisms based on both the intensity variation and wavelength shift are employed to investigate the performance of the RI sensor, with the assistance of leaky-mode and MMI theories. By monitoring the output intensity difference and the wavelength shift, the proposed RI sensor exhibits high average sensitivities of 185 dB/RIU and 3912 nm/RIU in a broad range from 1.339 to 1.443, respectively. The operating range and sensitivity can be adjusted by controlling the interaction length, which is appealing for a wide range of applications in industry and bioscience research.

Download Full-text

High Sensitivity Refractive Index Sensor Based on the Excitation of Long-Range Surface Plasmon Polaritons in H-Shaped Optical Fiber

Sensors ◽

10.3390/s20072111 ◽

2020 ◽

Vol 20 (7) ◽

pp. 2111 ◽

Cited By ~ 5

Author(s):

Nelson Gomez-Cardona ◽

Erick Reyes-Vera ◽

Pedro Torres

Keyword(s):

Refractive Index ◽

Optical Fiber ◽

Long Range ◽

Surface Plasmon ◽

High Sensitivity ◽

Refractive Index Sensor ◽

Promising Alternative ◽

Sensor Performance ◽

Wide Range ◽

Sensor Structure

In this paper, we propose and numerically analyze a novel design for a high sensitivity refractive index (RI) sensor based on long-range surface plasmon resonance in H-shaped microstructured optical fiber with symmetrical dielectric–metal–dielectric waveguide (DMDW). The influences of geometrical and optical characteristics of the DMDW on the sensor performance are investigated theoretically. A large RI analyte range from 1.33 to 1.39 is evaluated to study the sensing characteristics of the proposed structure. The obtained results show that the DMDW improves the coupling between the fiber core mode and the plasmonic mode. The best configuration shows 27 nm of full width at half maximum with a resolution close to 1.3 × 10 − 5 nm, a high sensitivity of 7540 nm/RIU and a figure of merit of 280 RIU − 1 . Additionally, the proposed device has potential for multi-analyte sensing and self-reference when dissimilar DMDWs are deposited on the inner walls of the side holes. The proposed sensor structure is simple and presents very competitive sensing parameters, which demonstrates that this device is a promising alternative and could be used in a wide range of application areas.

Download Full-text

GaN-Based High-Contrast Grating for Refractive Index Sensor Operating Blue–Violet Wavelength Region

Sensors ◽

10.3390/s20164444 ◽

2020 ◽

Vol 20 (16) ◽

pp. 4444

Author(s):

Yuusuke Takashima ◽

Masanobu Haraguchi ◽

Yoshiki Naoi

Keyword(s):

Refractive Index ◽

Chemical Stability ◽

Simple System ◽

Refractive Index Sensor ◽

Field Calculation ◽

High Contrast ◽

High Chemical ◽

Wide Range ◽

High Contrast Grating ◽

High Chemical Stability

Owing to its versatility, optical refractive index (RI) sensors with compact size and high chemical stability are very suitable for a wide range of the applications in the internet of things (IoT), such as immunosensor, disease detection, and blood mapping. In this study, a RI sensor with very simple system and high chemical stability was developed using GaN-based high-contrast grating (HCG). The designed HCG pattern was fabricated on GaN-film grown on c-plane sapphire substrate. The fabricated GaN-HCG sensor can detect minuscule RI change of 1.71 × 10–3 with extreme simple surface normal irradiation system. The light behavior inside the GaN-HCG was discussed using numerical electromagnetic field calculation, and the deep understand of the sensing mechanism was provided. The simple system and very high chemical stability of our sensor exploit RI sensing applications in IoT society.

Download Full-text