Abstract:
In this thesis, three high-yielding plasmonic refractive index sensors are proposed to satisfy the
current sensing demands in different sectors, for example, medical, forensic, and industrial. The
proposed works employ a straight waveguide and octagonal ring resonator, a PCF-SPR sensor
using symmetrical arrays of plasmonic layers, and another PCF-SPR sensor with dual plasmonic
layers. COMSOL Multiphysics is chosen as the wave-solver, which inherently deploys the Finite
Element Method. The re-simulations of existing structures corroborate the computational accuracy
of COMSOL Multiphysics. Furthermore, the first two sensors fabricated through nanoimprint
lithography technique and the stack-and-draw approach, respectively, exhibit linear correlation
with the refractive index and the resonant wavelength. Moreover, the structural parameters of the
plasmonic sensors are sensitive to variations. Thus, the suggested sensors undergo extensive
simulations and optimization processes to maximize their performance. The proposed first work
with the concentric octagonal-ring resonator exhibits a maximum sensitivity of 13157, and a high
dip strength of 0.8311 nm/RIU is obtained after optimization. This proposed work is deployed to
detect various types of fluids like air, optic oil, and different types of water. The proposed first
PCF-SPR sensor displays a wavelength sensitivity of 85,300 nm/RIU and amplitude sensitivity of
800.037 RIU-1
. The device has also shown FOM of 370.8 RIU-1 which denotes high accuracy and
reliability. A novel parameter was proposed in this work named Peak Amplitude Difference
Sensitivity (PADS) for higher precision interrogation in case of multiple peak analysis. The
proposed third work with dual plasmonic layer shows an initial wavelength sensitivity of 24,000
nm/RIU and 34,000 nm/RIU for two different peaks from 2 different regions. After optimization,
the wavelength sensitivity of the second peak was achieved 1,12,500nm/RIU which is one of the
highest among its competitors. The amplitude sensitivity was found 1248 RIU-1
. The structural
parameters will be optimized to maximize the performance of the suggested refractive index sensor
in future
Description:
Supervised by
Prof. Dr. Syed Iftekhar Ali,
Department of Electrical and Electronics Engineering (EEE)
Islamic University of Technology (IUT)
Board Bazar, Gazipur-1704, Bangladesh
