scholarly journals Significantly enhanced coupling effect and gap plasmon resonance in a MIM-cavity based sensing structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuan-Fong Chou Chau ◽  
Tan Yu Ming ◽  
Chung-Ting Chou Chao ◽  
Roshan Thotagamuge ◽  
Muhammad Raziq Rahimi Kooh ◽  
...  

AbstractHerein, we design a high sensitivity with a multi-mode plasmonic sensor based on the square ring-shaped resonators containing silver nanorods together with a metal–insulator-metal bus waveguide. The finite element method can analyze the structure's transmittance properties and electromagnetic field distributions in detail. Results show that the coupling effect between the bus waveguide and the side-coupled resonator can enhance by generating gap plasmon resonance among the silver nanorods, increasing the cavity plasmon mode in the resonator. The suggested structure obtained a relatively high sensitivity and acceptable figure of merit and quality factor of about 2473 nm/RIU (refractive index unit), 34.18 1/RIU, and 56.35, respectively. Thus, the plasmonic sensor is ideal for lab-on-chip in gas and biochemical analysis and can significantly enhance the sensitivity by 177% compared to the regular one. Furthermore, the designed structure can apply in nanophotonic devices, and the range of the detected refractive index is suitable for gases and fluids (e.g., gas, isopropanol, optical oil, and glucose solution).

2021 ◽  
Author(s):  
Yuan-Fong Chou Chau ◽  
Tan Yu Ming ◽  
Chung-Ting Chou Chao ◽  
Roshan Thotagamuge ◽  
Muhammad Raziq Rahimi Kooh ◽  
...  

Abstract Herein, we design a high sensitivity with a multi-mode plasmonic sensor based on the square ring-shaped resonators containing silver nanorods together with a metal-insulator-metal bus waveguide. The finite element method is used to analyze the transmittance properties and electromagnetic field distributions of the structure in detail. Results show that the coupling effect between the bus waveguide and the side-coupled resonator can enhance by generating gap plasmon resonance among the silver nanorods, increasing the cavity plasmon mode in the resonator. The suggested structure obtained relatively high sensitivity and acceptable figure of merit and quality factor of about 2473 nm/RIU (refractive index unit), 34.18 1/RIU and 56.35, respectively. The achieved plasmonic sensor is ideal for lab-on-chip in gas and biochemical analysis and can significantly enhance the sensitivity by 177% compared to the regular one. The designed structure can apply in nanophotonic devices, and the range of the detected refractive index is suitable for gases and fluids (e.g., gas, isopropanol, optical oil and glucose solution).


Nanomaterials ◽  
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 ◽  
...  

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).


Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1399 ◽  
Author(s):  
Chung-Ting Chou Chao ◽  
Yuan-Fong Chou Chau ◽  
Hung Ji Huang ◽  
N. T. R. N. Kumara ◽  
Muhammad Raziq Rahimi Kooh ◽  
...  

We numerically and theoretically investigate a highly sensitive and tunable plasmonic refractive index sensor that is composed of a metal-insulator-metal waveguide with a side-coupled nanoring, containing silver nanorods using the finite element method. Results reveal that the presence of silver nanorods in the nanoring has a significant impact on sensitivity and tunability performance. It gives a flexible way to tune the system response in the proposed structure. Our designed sensor has a sensitivity of 2080 nm/RIU (RIU is the refractive index unit) along with a figure of merit and a quality factor of 29.92 and 29.67, respectively. The adequate refractive index sensitivity can increase by adding the silver nanorods in a nanoring, which can induce new surface plasmon polaritons (SPPs) modes that cannot be found by a regular nanoring. For a practical application, a valid introduction of silver nanorods in the nanoring can dramatically reduce the dimension of the proposed structure without sacrificing performance.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3181 ◽  
Author(s):  
Kunhua Wen ◽  
Li Chen ◽  
Jinyun Zhou ◽  
Liang Lei ◽  
Yihong Fang

In this paper, multiple Fano resonances preferred in the refractive index sensing area are achieved based on sub-wavelength metal-insulator-metal (MIM) waveguides. Two slot cavities, which are placed between or above the MIM waveguides, can support the bright modes or the dark modes, respectively. Owing to the mode interferences, dual Fano resonances with obvious asymmetrical spectral responses are achieved. High sensitivity and high figure of merit are investigated by using the finite-difference time-domain (FDTD) method. In view of the development of chip-scale integrated photonics, two extra slot cavities are successively added to the structure, and consequently, three and four ultra-sharp Fano peaks with considerable performances are obtained, respectively. It is believed that this proposed structure can find important applications in the on-chip optical sensing and optical communication areas.


Author(s):  
Zhaojian Zhang ◽  
Junbo Yang ◽  
Xin He ◽  
Jingjing Zhang ◽  
Jie Huang ◽  
...  

A plasmonic refractive index (RI) sensor based on metal-insulator-metal (MIM) waveguide coupled with concentric double rings resonator (CDRR) is proposed and investigated numerically. Utilizing the novel supermodes of the CDRR, the FWHM of the resonant wavelength can be modulated, and a sensitivity of 1060 nm/RIU with high figure of merit (FOM) 203.8 is realized in the near-infrared region. The unordinary modes as well as the influence of structure parameters on the sensing performance are also discussed. Such plasmonic sensor with simple framework and high optical resolution could be applied to on-chip sensing systems and integrated optical circuits.


2021 ◽  
Vol 9 ◽  
Author(s):  
Rahul Kumar Gangwar ◽  
Rui Min ◽  
Santosh Kumar ◽  
Xiaoli Li

In this article, a D-shaped optical fiber refractive index (RI) sensor based on surface plasmon resonance effect is demonstrated. The gold film is placed at the flat portion of the optical fiber along with the sensing analytes of the different RIs to excite the plasmonic interactions. Sensing properties are investigated by using the finite element method. The maximum sensitivity of the proposed sensor is achieved as high as 20863.20 nm/RIU with the maximum resolution of 4.79 × 10−6 RIU and figure of merit of 308.38 RIU−1 for an analyte with RI 1.43 by optimizing the different parameters of the sensor with maximum phase matching between the core mode and surface plasmon mode. The high sensitivity of the sensor offers a promising approach for the detection of unknown RI analyte in chemical and biological fields in the near-infrared region.


Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Rostamian ◽  
Ehsan Madadi-Kandjani ◽  
Hamed Dalir ◽  
Volker J. Sorger ◽  
Ray T. Chen

Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to use such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of n g  = 73 and a strong localization of modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when combined with integrated with quantum cascade laser and detectors.


Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1325 ◽  
Author(s):  
Ru-Jing Sun ◽  
Hung Ji Huang ◽  
Chien-Nan Hsiao ◽  
Yu-Wei Lin ◽  
Bo-Huei Liao ◽  
...  

A TiN-based substrate with high reusability presented high-sensitivity refractive index measurements in a home-built surface plasmon resonance (SPR) heterodyne phase interrogation system. TiN layers with and without additional inclined-deposited TiN (i-TiN) layers on glass substrates reached high bulk charge carrier densities of 1.28 × 1022 and 1.91 × 1022 cm−3, respectively. The additional 1.4 nm i-TiN layer of the nanorod array presented a detection limit of 6.1 × 10−7 RIU and was higher than that of the 46 nm TiN layer at 1.2 × 10−6 RIU when measuring the refractive index of a glucose solution. Furthermore, the long-term durability of the TiN-based substrate demonstrated by multiple processing experiments presented a high potential for various practical sensing applications.


Author(s):  
E. Gazzola ◽  
A. Pozzato ◽  
G. Ruffato ◽  
E. Sovernigo ◽  
A. Sonato

AbstractSurface plasmon resonance biosensors have recently known a rapid diffusion in the biological field and a large variety of sensor configurations is currently available. Biological applications are increasingly demanding sensor miniaturization, multiple detection in parallel, temperature-controlled environment and high sensitivity. Indeed, versatile and tunable sensing platforms, together with an accurate biological environment monitoring, could improve the realization of custom biosensing devices applicable to different biological reactions. Here we propose a smart and high throughput fabrication protocol for the realization of a custommicrofluidic plasmonic biochip that could be easily tuned and modified to address different biological applications. The sensor chip here presented shows a high sensing capability, monitored by an accurate signal calibration in the presence of concentration and temperature variation.


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