Optical control of single-photon negative-feedback avalanche diode detector

We experimentally demonstrate optical control of negative-feedback avalanche diode detectors using bright light. We deterministically generate fake single-photon detections with a better timing precision than normal operation. This could potentially open a security loophole in quantum cryptography systems. We then show how monitoring the photocurrent through the avalanche photodiode can be used to reveal the detector is being blinded.