We report an eight-element, linear-array, single-photon detector that uses multiple fibers of differing lengths coupled to a single detector, the timing information from which reveals the position in which the photon was measured. Using two such arrays and two detectors we measure the correlations of photons produced by parametric downconversion, without recourse to mechanical scanning. Spatial light modulators acting as variable focal length lenses positioned between the downconversion crystal and the arrays allow us to switch between measurement of position, transverse momentum, or intermediate bases. We observe the product of the variances of the conditional probabilities for position and momentum to be more than an order of magnitude below the classical limit, realizing a full-field demonstration of the Einstein-Podolsky-Rosen paradox. Such, multistate measurement technologies allow access to the higher information content of the photon based upon spatial modes.
- optical field
- quantum physics
- multiple fibers
Leach, J., Warburton, R., Ireland, D. G., Izdebski, F., Barnett, S., Yao, A., ... Padgett, M. J. (2012). Quantum correlations in position, momentum, and intermediate bases for a full optical field of view. Physical Review A, 85(1), . https://doi.org/10.1103/PhysRevA.85.013827