Femtosecond carrier dynamics in graphite

Abstract

We present a comprehensive report of pump-probe reflectivity and transmission measurements on highly oriented pyrolytic graphite with 50 fs time resolution. The experiments trace the generation, relaxation, and recombination of nonequilibrium carriers in a quasi-two-dimensional semimetallic solid over a wide range of experimental parameters. The fluence of excitation at hν=2.0 eV was varied between ${10}^{\mathrm{-}6}$ and ${10}^{\mathrm{-}2}$ J/${\mathrm{cm}}^2$, below the threshold for optical damage, while probe pulses in the photon energy range 1.5hν