An experiment is proposed in which the overall path taken by a photon is indicated\nby the timing of a twin herald photon, while a particular segment\nof that path is determined by interference. The needed coincident pairs of\nphotons are generated by type I spontaneous-parametric-down-conversion\n(SPDC) and diffraction-selected by a grating at the frequency of a two-photon\nstate. This is to be divided into two one-photon states of high coherence\nlength. Upon experimental confirmation that their count coincidences have\nbeen maintained, the two single photons are to be used as a timing herald and\nsource for an unequal path interferometer. A photon�s path through the interferometer\nvia a short arm is indicated by count synchronization with the\nherald. The exit output port used and resulting final detection location are\ndetermined by the phase in the long arm. If output port usage can be controlled\nby the phase in the photon-free arm, the path of the photon as particle\nwill have been controlled by interference with an accompanying photon-\nempty wave.
Loading....