Experimental controlled-NOT logic gate for single photons in the coincidence basis
T. B. Pittman, Michael J. Fitch, B. C. Jacobs, J. D. Franson · Physical Review A · 2003
We report a proof-of-principle demonstration of a probabilistic controlled-NOT gate for single photons. Single-photon control and target qubits were mixed with a single ancilla photon in a device constructed using only linear optical elements. The successful operation of the controlled-NOT gate relied on post-selected three-photon interference effects, which required the detection of the photons in the output modes.