  Achieving optical operation of logic elements, especially those that involve
2D layers, can open the long sought era of optical computing. However, the
efficient optical modulation of the electronic properties of 2D materials
including memory effect is currently missing. Here we report a fully optical
control of the conductivity of a graphene with write/erase option yet under
ultralow optical fluence. The competition between light-induced charge
generation in ferroelectric-photovoltaic substrate with subsequent relaxation
processes provides the selective photocarrier trapping control affecting the
doping of 2D overlayer. These findings open the road to photonic control of 2D
devices for all -optical modulators and a variety of all-optical logic
circuits, memories and field-effect transistors.
