Observation Of Femtosecond Infrared Luminescence In Gold (Vol 100, 125405, 2019)

Femtosecond infrared luminescence in Au was observed using the upconversion technique. The instantaneous luminescence intensity for a sample with an appropriate surface roughness was three orders of magnitudes higher than that for a flat film and comparable to the hot luminescence in InAs. The time-resolved spectra from 0 to 1 ps exhibited broad features spreading from 0.3 to 1.04 eV, indicating a continuous joint density of states around the Fermi energy. In terms of a simple model that considers nonthermal and thermal carriers for describing the hot luminescence, most of the characteristic behaviors are semiquantitatively understood.