Abstract

If a metal is excited by laser pulses for which the pulse duration is less than or comparable to the hot electron energy loss lifetime (τ_e), a transient inequality between the effective electron and lattice temperatures (T_e and T_ℓ, respectively) occurs [1]. Previous femtosecond thermotransmissivity [2] (thermoreflectivity [3,4]) of Cu (Au) have successfully been used to temporally resolve the decay of the hot electrons. These experiments relied on the fact that changes in the occupancy of electronic states near the Fermi level modulates the optical properties of the metal [5]. Although results for τ_e showed agreement with a calculation of electron-phonon coupling [6], there remains unresolved the role of lattice imperfections on hot electron energy loss and transport.

© 1990 Optical Society of America