Various resonance modes, high transmission, and quality factor with simple design are highly desirable parameters for realizing nano-integrated plasmonic devices. In the context, a plasmonic structure consisting of two straight waveguides MIM coupled one central defective circular nano-disk resonator (CNDR) is proposed in this work. The insulator and metal of the proposed plasmonic filter are air and silver, respectively. The plasmonic filter is designed and investigated numerically by using the finite difference time domain method (FDTD). Our simulation results indicate that the proposed plasmonic filter has two transmission peaks with a maximum transmission equal to 80 and 70 percent. The advantages of the proposed filter are the various resonance modes with high transmission peaks and high quality factor which reaches 35.27. In view of these features, our proposed structure of plasmonic filter has the potential to be employed in various devices such as plasmonic demultiplexers and sensors for optical communication purposes.

In this paper, a plasmonic sensor is proposed based on a metal-insulator-metal waveguide coupled with a double-triangle resonator. The sensing structure is numerically and theoretically investigated using the two-dimensional finite difference time domain (FDTD) method. The results show the presence of a linear relationship between the materials refractive indices and the sensor’s wavelength resonances. The proposed structure revealed a high sensitivity value, reaching the maximum value for mode 1 S mode1 = 1374 nm/RIU, and for mode 2 S mode2 = 2365 nm/RIU. The proposed sensor can be classified as a high-performance nano-sensor that can be used to identify different materials.

In this study, we propose an ultra-wideband bandstop filter (UWB-BSF) using a plasmonic MIM waveguide coupled with a stub cavity that is investigated using finite-difference time-domain (FDTD). Air and silver are used as insulators and metals, respectively; silver is characterized by the Drude model. The structure can filter the optical telecommunication wavelengths of 1550 nm and 1310 nm. The transmission peak and the resonance wavelength of the basic structure can be tuned by varying the stub resonator’s length and width. In order to improve the filtering function of the bandstop filter at broad bandwidth in the NIR region with maximum transmission peak, the number of stub resonators is increased to two, three, and four stubs with properly studied lengths and a proper horizontal distance between each two stubs. The bandwidth is enhanced from 350 nm, with two stubs, to 620nm, with three stubs, and 770 nm, with four stubs, respectively. The corresponding filtered wavelength ranges are [1600nm-1950nm], [1330nm-1950nm] and [1180nm-1950nm] respectively. Moreover, with the increase in the number of stubs, the center wavelength achieves a blue shift to lower wavelengths. Further, the paper provides significant applications for plasmonic bandstop filters in highly integrated optical circuits.

A novel design of an integrated ring cavity consisting of two merged and opposite triangles formed on a metal-insulator-metal (MIM) waveguide is suggested and analyzed for refractive index sensing application. The cavity design can be optimized provide the best sensing performance. In this work, we simulated numerically the device design by utilizing the finite-difference-time-domain (FDTD) technique in a two-dimensional (2D) structure. The detection of the refractive index changes was numerically simulated and analyzed using RSoft™. Small variations in the geometric parameters can enhance the sensitivity achieved, which we found to be 3575 nm/RIU. We believe that the sensor can achieve a resolution of 2.79×10−6. The structure proposed has a simple design for easy and compact realization, paving the way of detecting rare biochemical analytes and for finding applications in optical filters.

In this study, we propose and simulate in the NIR region a tunable stop-band filter based on an MIM waveguide coupled to a triangular cavity. The transmission spectra of the filter are obtained using the R-Soft CAD software based on the two-dimension (2D) finite-difference time-domain (FDTD) method, which uses perfectly matched layers (PML) to absorb the outgoing energy fields. A stop-band plasmonic filter with a large bandwidth and high bandpass transmission is achieved by adding another triangular cavity resonator. One can also control the range filtered and the shift of the central wavelength by tuning the second triangular cavity parameters. This structure has important applications in highly integrated photonic circuits.