Photonic signals were efficiently stored in a semiconductor-based memory ce
ll. The incident photons were converted to electron-hole pairs that were lo
cally stored in a quantum well that was Laterally modulated by a field-effe
ct tunable electrostatic superlattice. At Large superlattice potential ampl
itudes, these pairs were stored for a time that was at least five orders of
magnitude Longer than their natural Lifetime. At an arbitrarily chosen tim
e, they were released in a short and intense flash of incoherent light, whi
ch was triggered by flattening the superlattice amplitude.