Development of a Nanoplasmonic Ruler

Abstract

The ability to simultaneously and independently measure the refractive index and thickness of a thin film is of tremendous interest in the fields of material science and biology. For example, via these measurements it can be possible to thoroughly investigate the effects of temperature on a material or the conformational changes of a cell membrane upon the binding of a protein. In this thesis, a dual parametric nanoplasmonic ruler has been developed to enable this simultaneous and independent measurement. A ruler based on a dual-sized nanodisks design has been explored and successfully fabricated using hole-mask colloidal lithography. Milling parameters have been optimised to enable the formation of a topographically flat surface on these rulers. The fabricated rulers have been characterised using atomic force microscopy, scanning electron microscopy, spectrophotometry and bulk refractive index sensitivity measurements. The functionality of the ruler has been tested using lipid adsorption followed by the subsequent binding of DNA and proteins.