Enhanced coupling efficiency in metal – dielectric – metal waveguide-ring structure for plasmonic temperature sensor and sucrose concentration detector

In this paper, we propose a sensing structure based on metal-dielectric-metal waveguide technology, which comprises of two square ring resonators side linked to the bus waveguide and operates in the infrared and near infrared regions. The results revealed that the proposed device enormously enhanced the coupling effect between the main waveguide and the cavity thereby increasing the sensor's performance parameters. The device has an ability to act as refractive index sensor, temperature sensor for ethanol and sucrose concentration detector with sensitivities of 2880 nm/RIU, 1.375 nm/℃, and 1750 nm/RIU, respectively. The device is also optimized by changing the structural parameters and material medium. The sensor design is simple to construct, has better sensing features, and is small in size. Thus, the proposed plasmonic sensor is relevant for lab-on-chip gas and biochemical detection (having an optical refractive index between 1.0 and 1.5).