Real-time plasmon resonance tuning of liquid Ga nanoparticles by in situ spectroscopic ellipsometry

Liquid Ga nanoparticles have been deposited on sapphire substrates at room temperature. The optical evolution of Ga nanoparticle surface plasmon resonance during deposition has been characterized by in situ real-time spectroscopic ellipsometry to control and tune the plasmon resonance photon energy. The existence of both longitudinal and transverse modes for spheroidal Ga nanoparticles supported on a sapphire substrate is demonstrated and the dependence of the longitudinal and transverse plasmon energies on particle size is discussed. Stability of the Ga surface plasmon resonance to air exposure and high temperature is also demonstrated.