Analysis, design and simulation of MIM plasmonic filters with different geometries for technical parameters improvement

Abstract

In this paper, four optical filter topologies based on metal–insulator–metal waveguides are proposed and the designed structures are investigated numerically using finite-difference time-domain method. Triangular-shaped adjunctions have been added to the filter structures to improve their transmission spectrum. These improved structures consist of air as the insulator and silver as the metal. The relative permittivity of metal has been described via the Drude, Drude–Lorentz, and Palik models. The first filter’s transmission spectrum shows an acceptable transmittance. In the second optimized filter, the transmission spectrum has been improved. The transmittance spectrum can be tuned through adjusting the edge of the triangle in these four optimized filters. As a result, the bandwidths of resonance spectra can be adjusted. The theory of such tapered structures will be investigated by the tapered transmission line and will be solved with the transfer matrix method. This method shows a better performance and higher transmission efficiency in comparison with the basic structures. On the other hand, the final filter has been chosen as the best one because of its hexagonal resonator. The main reason for having a better result is due to a longer interaction length in comparison with the circular resonator. This in turn creates much better energy coupling and results in higher transmission.

Design and Simulation of a Plasmonic Refractive Index Nano-Sensor Based on Tunable Fano Resonance

“…This is because SPPs can overcome diffraction limit (Barnes et al 2003), and therefore they are appropriate for highly integrated photonic and plasmonic circuit applications. Plasmonic devices such as optical switches (Khani et al 2021;Wang et al 2012;Karimi et al 2021), splitters (He et al 2010;Yu et al 2017), demultiplexers (Wen et al 2012;Hajshahvaladi et al 2019), filters (Wu et al 2016;Shafagh et al 2020), and sensors (Wang et al 2019) have been investigated frequently. Lately, plasmonic sensors have drawn attention due to their smaller size and also analogous operational parameters compared to other optical sensors (Zhang et al 2018).…”

Highly Sensitive THz Refractive Index Sensor Based on Folded Split-Ring Metamaterial Graphene Resonators

“…Graphene is a two-dimensional (2D) single-layer structure in which carbon atoms are coordinated into a honeycomb structure. In the far-infrared to THz band, graphene supports surface plasmonic polaritons (SPPs) [36][37][38][39][40][41][42] and they have strong electric field constraints and low loss optical attributes compared to other plasmonic metals such as gold and silver [43], [44]. Also, graphene plasmonic sensors can improve sensing characteristics due to the high amount of modal confinement in graphene-insulator surfaces [45].…”