ULTRAFAST RELAXATION OF ELECTRONS PROBED BY SURFACE-PLASMONS AT A THIN SILVER FILM

We present a novel subpicosecond optical transient-reflection method, which employs the surface-plasmon resonance of a thin silver film as a very sensitive probe to study small transients of the effective electron and lattice temperature. By measuring under surface-plasmon resonant and nonresonant conditions, we can discriminate between lattice and electron heating. We find a change of the lattice and electron temperature of respectively, Tl=0.10(5) K and Te=3090 K for an intensity of 180 W cm-2 and an electron-phonon energy relaxation time of 670(70) fs. © 1990 The American Physical Society.