MIM waveguide system with independently tunable double resonances and its application for two-parameter detection

Abstract

A metal–insulator–metal (MIM) waveguide system consisting of a MIM waveguide, a ring cavity, and a semi-ring cavity is proposed. Using the finite element method, the transmission characteristics of the MIM waveguide system are discussed under the different geometry parameters. By detecting the resonance wavelength and varying the refractive index, the sensing performance of the MIM waveguide system is analyzed. The proposed structure can be used as a refractive index sensor with the maximum sensitivity of 2412 nm/RIU. Due to isolating the ring cavity and semi-ring cavity, the independent tuning of double resonances can be realized by changing the refractive index of the insulator in the ring cavity or the semi-ring cavity. Benefiting from two independent refractive index sensing modes, the structure with two isolated resonators can realize the simultaneous measurement of glucose solution concentration and blood plasma concentration. The sensitivity of glucose solution sensing in the ring cavity is 0.13133 nm/(g/L). Meanwhile, the blood plasma concentration detection in the semi-ring cavity is realized with the sensitivity of 0.358 nm/(g/L). The system with two isolated cavities has the potential to be used as an efficient nano sensor, which can achieve simultaneous measurement of two parameters.

MIM plasmonic sensors based on single-side ring cavity with one stub and their applications

“…The MIM waveguide structures can generate various phenomena, such as Fano resonance and Lorentzian resonance [9,10]. Among them, Fano resonance, resulting from the interference between a continuous state and a discrete state, is an exemplary resonant phenomenon that exhibits a sharp and asymmetrical line profile [9].…”

A High-Sensitivity Refractive Index Nano-Sensor Structure Based on MIM Waveguide

“…With the fast advancement of a modern science and techo-technology, all kinds of information acquisition and application are transmitted with ultra-fast speed and large amount of storage, so the integration of traditional microelectronics as information carrier has been insufficient to accommodate the current needs of social advancement and people's life. SPPs, a mixed excited state, are caused by the local coordination of free electrons and photons [1]. And SPPs have been widely studied and paid attention to because they can break the diffraction limit of light at nanometer size and have powerful light field limiting and local field boosting capabilities [2].…”