  We present a novel optical transient absorption and reflection microscope
based on a diffraction-limited pump pulse in combination with a wide-field
probe pulse, for the spatio-temporal investigation of ultrafast population
transport in thin films. The microscope achieves a temporal resolution down to
12 fs and simultaneously provides sub-10 nm spatial accuracy. We demonstrate
the capabilities of the microscope by revealing an ultrafast excited-state
exciton population transport of up to 32 nm in a thin film of pentacene and by
tracking the carrier motion in p-doped silicon. The use of few-cycle optical
excitation pulses enables impulsive stimulated Raman micro-spectroscopy, which
is used for in-situ verification of the chemical identity in the 100 - 2000
cm-1 spectral window. Our methodology bridges the gap between optical
microscopy and spectroscopy allowing for the study of ultrafast transport
properties down to the nanometer length scale.
