A single-mode tunable plasmonic sensor based on an 8-shaped resonator for cancer cell detection

Abstract

In this paper, a novel 8-shaped resonator coupled to metal–insulator–metal waveguides is used for designing plasmonic filters and sensors. The resonator supports two resonance modes, which result in peaks in the transmission spectrum of the structure. A Q-factor of 247.4 which can reach up to 270 at the wavelength of 1187.5 nm is observed. By placing vertical and horizontal metal blades in the resonator, two tunable single-mode plasmonic filters are obtained at the first and second resonance modes, respectively. The effect of structural parameters on the transmission spectrum is investigated using the finite-difference time-domain (FDTD) method. Based on the obtained results, the proposed plasmonic structure can be used for biosensing applications such as the detection of basal cancer cells with a sensitivity of 1200 nm/RIU. It is of great significance that both the sensitivity and Q-factor values for the proposed structure are higher than most recent sensors reported in the literature. Therefore, the proposed structure is a potentially promising candidate for filtering and sensing applications.

Plasmon-Enhanced Refractive Index Sensing of Biomolecules Based on Metal–Dielectric–Metal Metasurface in the Infrared Regime

“…Silver exhibits higher sensitivity to changes in background RI than gold and aluminum in the optical and infrared regimes . Single-mode optical sensors detect biomolecules but have an inherent risk of errors due to limited information retrieval and the absence of redundant confirmation in a single resonance mode. , In contrast, multiple resonance modes provide improved information retrieval, redundant verification, and enhanced sensitivity. Consequently, these biosensors hold substantial potential for diverse applications such as measuring media concentration, identifying individual cancer cells, and performing nucleic acid–based analysis. − …”