en نانوفوتونیک و ساختارهای نانویی Nanophotonics and Nanostructures پژوهشي Research <div style="text-align: justify;"><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">In this paper, a plasmonic refractive index sensor based on </span></span></span><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">a<span style="color:black"> graphene ribbon array is proposed. Graphene ribbons are employed to excite surface plasmon waves, providing a subwavelength sensor. </span>The structure exhibits a resonance feature, enabling wavelength-selective operation.<span style="color:black"> It acts like a band rejection filter. The filtering behavior depends on the absorption of the incident light from an incident port at specific wavelengths. The rejected and absorbed bands depend on the structural parameters of the proposed sensor, such as the refractive index of the material surrounding the ribbons. A change in the refractive index of the material would change the wavelength of the transmitted lightwaves out of the sensor, providing a measuring approach to detect various transparent materials. The operation of the structure is simulated using the finite difference time domain (FDTD) numerical method and verified utilizing a simple characteristic equation. Due to the chemical potential dependency of graphene conductivity, the proposed sensor can be calibrated via an external voltage bias. The optimization of the proposed sensor performance can be accomplished through straightforward utilization of calculus. The proposed subwavelength sensor is widely applicable in terahertz-band applications, such as biological and chemical sensing.</span></span></span></div> Graphene ribbon, Optimization of sensor, Plasmonic structure, Refractive index sensor, Subwavelength structure, Wavelength selective structure. 129 138 http://ijop.ir/browse.php?a_code=A-10-781-1&slc_lang=en&sid=1 Alireza Dolatabady alireza.dolatabady@abru.ac.ir 10031947532846005456 10031947532846005456 Yes Department of Electrical Engineering, Faculty of Engineering, Ayatollah Boroujerdi University, Boroujerd, Iran Nader Habibi habibi@abru.ac.ir 10031947532846005457 10031947532846005457 No Ayatollah Boroujerdi University