scholarly journals Self-Referenced Refractive Index Biosensing with Graphene Fano Resonance Modes

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 400
Author(s):  
Xiaoyu Dai ◽  
Banxian Ruan ◽  
Yuanjiang Xiang

A hybrid structure composed of periodic monolayer graphene nanoribbons and a dielectric multilayer structure was designed to generate a Fano resonance (FR). The strong interaction between the surface plasmon resonance of graphene and the dielectric waveguide mode results in the FR. The finite element method is utilized to investigate the behaviors of the FR, and it matches well with the theoretical calculations using rigorous coupled wave theory. The results demonstrate that the profile of the FR can be passively tuned by the period of the graphene nanoribbons and actively tuned by the Fermi level of the graphene. The decoupled nature of the FR gives it potential applications as a self-calibrated refractive index biosensor, and the sensitivity can reach as high as 4.615 μm/RIU. Thus, this work provides a new idea for an excellent self-referencing refractive index biosensor.

2020 ◽  
Vol 13 (4) ◽  
pp. 119-134
Author(s):  
Lin Chen ◽  
Bo Liu ◽  
Yiming Zhu

We have experimentally excited terahertz multipolar Fano resonances in two asymmetrical metal particles: a defective corrugated metallic disk(CMD) structure and a hybrid structure consisted of a C-shaped resonator and a CMD. Furthermore, the Fano resonance modes can also be excited by the interaction between plasmonic waveguide and CMD. Our findings have shed light into the terahertz multipolar Fano resonances in asymmetrical CMD and opened the way to the design of terahertz plasmonic devices.


Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4125
Author(s):  
Xiaoyu Yang ◽  
Ertian Hua ◽  
Hao Su ◽  
Jing Guo ◽  
Shubin Yan

Herein, a nanosensor structure is proposed, which comprises metal-insulator-metal (MIM) waveguide with stub and circular ring cavity with a stub (CRCS). The phenomenon of Fano resonance appears in the transmission spectrum, which is formed by interaction between the narrowband mode of CRCS and broadband mode of stub on bus waveguide. The influence of geometric asymmetry on mode splitting of Fano resonance was discussed. The mode splitting of Fano resonance can vastly improve figure of merit (FOM) with a sight decrease of sensitivity. The best performance of the refractive-index nanosensor is attained, which is 1420 nm/RIU with a high FOM of 76.76. Additionally, the application of designed structure on temperature sensing was investigated, which has sensitivity of 0.8 nm/°C. The proposed structure also possesses potential applications on other on-chip nanosensors.


2020 ◽  
pp. 2150065
Author(s):  
Ying Chen ◽  
Jinggang Cao ◽  
Yangmei Xu ◽  
Xinbei Gao ◽  
Jinchao Xie

A metal-dielectric-metal (MDM) waveguide coupled disk cavity structure with bimetallic baffle is proposed, which bases on the transmission characteristics of surface plasmon polaritons (SPPs) in subwavelength structure, and the absorption material InGaAsP is filled in the Fabry–Perot (F-P) cavity and disk cavity. The Fano resonance is an asymmetric spectral line formed by the destructive interference between the wide continuous state generated by the F-P resonator and the narrow discrete state interference generated by the disk cavity. Based on the coupled mode theory, the formation mechanism of the Fano resonance of the structure is qualitatively analyzed. The structure was simulated by finite element method to quantitatively analyze the influence of structural parameters and absorption material InGaAsP on the refractive index sensing characteristics. The proposed sensor yields sensitivity higher than 1360 nm/refractive index unit (RIU) and a figure of merit of [Formula: see text] by optimizing the geometry parameters and filling the absorption material InGaAsP. This structure has potential applications for high integration of nanosensors, slow-light devices, and nano-optical switches.


Author(s):  
Shubin Yan ◽  
Meng Zhang ◽  
Xuefeng Zhao ◽  
Yanjun Zhang ◽  
Jicheng Wang ◽  
...  

In this study, we design a new refractive index sensor based on a metal–insulator–metal waveguide coupled with a notched ring and vertical rectangular resonators. We use the finite element method to study the propagation characteristics of the sensor. According to the calculation results, the transmission spectrum exhibits a typical Fano resonance shape. The phenomenon of Fano resonance is caused by the coupling between the wide spectrum and narrow spectrum. In the design, the wide spectrum signal is generated by the vertical rectangular resonator, while the narrow spectrum signal is generated by the notched ring resonator. In addition, we varied the structural parameters of the resonators and filled the structure with media of different refractive indices to study the sensing properties. The maximum achieved sensitivity of the sensor reached 1071.4 nm/RIU. The results reveal potential applications of the coupled system in the field of sensors.


Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Xiangyang Li ◽  
Zongpeng Song ◽  
Huancheng Zhao ◽  
Wenfei Zhang ◽  
Zhenhua Sun ◽  
...  

In recent years, using two-dimensional (2D) materials to realize broadband photodetection has become a promising area in optoelectronic devices. Here, we successfully synthesized SnSe nanosheets (NSs) by a facile tip ultra-sonication method in water-ethanol solvent which was eco-friendly. The carrier dynamics of SnSe NSs was systematically investigated via a femtosecond transient absorption spectroscopy in the visible wavelength regime and three decay components were clarified with delay time of τ1 = 0.77 ps, τ2 = 8.3 ps, and τ3 = 316.5 ps, respectively, indicating their potential applications in ultrafast optics and optoelectronics. As a proof-of-concept, the photodetectors, which integrated SnSe NSs with monolayer graphene, show high photoresponsivities and excellent response speeds for different incident lasers. The maximum photo-responsivities for 405, 532, and 785 nm were 1.75 × 104 A/W, 4.63 × 103 A/W, and 1.52 × 103 A/W, respectively. The photoresponse times were ~22.6 ms, 11.6 ms, and 9.7 ms. This behavior was due to the broadband light response of SnSe NSs and fast transportation of photocarriers between the monolayer graphene and SnSe NSs.


Plasmonics ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. 1379-1385 ◽  
Author(s):  
Kristof Lodewijks ◽  
Jef Ryken ◽  
Willem Van Roy ◽  
Gustaaf Borghs ◽  
Liesbet Lagae ◽  
...  

Author(s):  
Shuangxiu Yuan ◽  
Xuebo Sun ◽  
Jing Li ◽  
Yan Li ◽  
Fufang Su ◽  
...  

Abstract We experimentally and theoretically investigate Fano-like resonance in large-area Au/SiO2/Au nano-patches meta-structure, which is originating from the coupling between Fabry Perot resonance and magnetic dipole resonance modes. A highly sensitive refractive index sensor based on the lineshape analysis is obtained. The extracted wavelength shift with the amount of substance of Hg2+ changing from 10-3 pmol to 1 nmol has a linear dependence, and the sensitivity can reach to ultra-low limit of detection (LOD) as 10-3 pmol. This study may provide an approach for the development and modification in sensing.


2020 ◽  
Vol 10 (4) ◽  
pp. 375-386 ◽  
Author(s):  
Jiankai Zhu ◽  
Xiangxian Wang ◽  
Yuan Wu ◽  
Yingwen Su ◽  
Tianxu Jia ◽  
...  

Abstract In this paper, we propose two kinds of composite structures based on the one- and two-dimensional (1D&2D) gold grating on a gold film for plasmonic refractive index sensing. The resonance modes and sensing characteristics of the composite structures are numerically simulated by the finite-difference time-domain method. The composite structure of the 1D gold semi-cylinder grating and gold film is analyzed first, and the optimized parameters of the grating period are obtained. The sensitivity and figure of merit (FOM) can reach 660RIU/nm and 169RIU−1, respectively. Then, we replace the 1D grating with the 2D gold semi-sphere particles array and find that the 2D grating composite structure can excite strong surface plasmon resonance intensity in a wider period range. The sensitivity and FOM of the improved composite structure can reach 985RIU/nm and 298 RIU−1, respectively. At last, the comparison results of the sensing performance of the two structures are discussed. The proposed structures can be used for bio-chemical refractive index sensing.


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