  Optical modulation of high-harmonics generation in solids enables the
detection of material properties such as the band structure and promising new
applications such as super-resolution imaging in semiconductors. Various recent
studies have shown optical modulation of high-harmonics generation in solids,
in particular, suppression of high-harmonics generation has been observed by
synchronized or delayed multi-pulse sequences. Here we provide an overview of
the underlying mechanisms attributed to this suppression and provide a
perspective on the challenges and opportunities regarding these mechanisms.
All-optical control of high-harmonic generation allows for femtosecond, and in
the future possibly subfemtosecond, switching, which has numerous possible
applications: These range from super-resolution microscopy, to nanoscale
controlled chemistry, and highly tunable nonlinear light sources.
