Photo-electron storage in a one-electron quantum dot

We report on the trapping, storage and detection of a single photo-electron in an electrostatic quantum dot defined by surface metallic gates on a GaAs/AlGaAs modulation doped heterostructure. The dot can be emptied and reset in a controlled fashion before the arrival of each photon. The trapped photo-electron is detected by the photoconductive gain mechanism of a point contact transistor integrated adjacent to the electron trap. Each photo-electron causes a persistent negative step in the transistor channel current. Such a controllable, non-invasive, single photo- electron detector could allow for quantum information transfer between flying photon qubits and stored electron qubits.