Geometrical effects on field enhancements and multiphoton luminescence of plasmonic gold nanoparticles

It is known that the sharpness of a plasmonic nanoparticle is connected to the localised field strength, however, this relationship has not been properly characterised. This thesis aims to analyse how the sharpness of gold nanorod tips influences the efficiency of luminescence and to investigate the multiphoton luminescence from gold nanoparticles for an excitation wavelength beyond 1000 nanometres. The thesis presents a semi-analytical model that is able to solve the field enhancement around the surface of nanorods. The thesis performs experimental studies using z-scan, non-linear microscopy and non-linear spectroscopy to successfully characterise the non-linear emission caused by gold nanoparticles.