Fine tuning of quantum particle plasmon

Abstract

It is of recent interest to study plasmonics of metallic and semiconductor particles that are so small that carriers in the conduction band are separated at discrete subbands due to quantum confinement. These small metallic and semiconductor particles are referred as quantum particles in the present work. The modifications of plasmons of quantum particles are studied in the framework of an electron-in-a-box model with an every-electron-count computational scheme. The quantum size effects are incorporated into the classic description of small particle plasmons with the emphasis on intra-subband fluctuations caused by the quantum confinement. The carrier redistribution at subbands is related to the environmental temperature via Fermi-Dirac distribution. Numerical results have shown that the frequency, the strength, and the shape of the plasmons are modified as a function of both particle size and temperature. The discovery suggests potential applications to tune the plasmonics of quantum particles externally and to calibrate the particle properties accounting to plasmonics. It is proposed that the environmental temperature can be conveniently controlled by evanescent light concentration, such as, laser beams in a slot waveguide.