INVESTIGATION OF NANOSTRUCTURES FOR HIGHLY SENSITIVE SURFACE PLASMON RESONANCE SENSORS

Abstract

An extensive study of Surface Plasmon Polaritons (SPPs) and their applications has been undertaken in this work. Highly sensitive surface plasmon resonance sensors, made of noble metals, as well as multilayer nanostructures, are investigated. Detailed simulations are performed to optimize and improve the structure of these sensors. Evanescent fields created on the surface of the sensor are evaluated. It is demonstrated theoretically and experimentally that sensor sensitivity can be increased significantly by choosing the right index of the prism used in our Kretschmann and Fixed Detector Kretschmann Spectrometers.

The interaction of the SPPs and CdSe/ZnS quantum dots that leads to Rabi splitting in the dispersion curve, is studied by COMSOL simulations in relation to the experimental photoluminescence data obtained previously in our research group. These simulations provide an explanation for the observed shift in the PL wavelength emitted by QDs when coupled to SPPs and meanwhile exposed to a 514 nm laser beam.

Additionally, a new metamaterial nanostructure, consisting of TiN, SiO2 and HfO2, is proposed and investigated for applications as an efficient solar absorber. This nanostructure increases absorption of the solar energy up to an unprecedented amount of 98% for wavelengths from 250 to 1100 nm. In case of indirect sunlight incidence, we see a continuous decrease in absorption by going to higher angles, but still it remains higher than 80% for majority of wavelengths for incidence angle less than 60 degrees.