Sub-optical-cycle control of light and matter

Many fundamental and ubiquitous physical phenomena have origin at the
ultrafast timescale. The possibility to investigate various primary
processes on their intrinsic timescales relies on the generation of
ultrashort pulses with widely tunable carrier frequency, from
ultraviolet to mid- and far-infrared. These optical waveforms allow the
investigation of microscopic light-matter interactions in a wide variety
of condensed material systems to unveil the deep origin of their
optoelectronic properties.
A novel idea consist in exploiting the optical field itself to control
the properties of crystals and nanostructures. With this approach, it
becomes possible to access phenomena occurring within a oscillation of
light as benchmarked by three experiments: i) optical response of
semiconducting nanostructures by impulsively exciting a plasma frequency
in mid-infrared range that establishes a plasmonic resonance; ii)
quasi-instantaneous localization of electronic wavefunctions in GaAs by
non-resonant bias with intense THz radiation; iii) ultrafast electron
transport driven by the peak electric field of a single-cycle optical
pulses focused on nanostructured gold circuits.