We demonstrate a new approach to measuring high-order temporal coherences that uses a four-element superconducting nanowire single-photon detector (SNSPD) in which four independent, single-photon-sensitive elements are interleaved over a single spatial mode of the optical beam. We show the power of this technique by measuring nth-order coherences (n = 2,3,4) both of a chaotic, pseudo-thermal source that exhibits high-order photon bunching (up to n!), and of a coherent state source for which all coherences are ~1. Our results demonstrate that using multiple detector elements to parse an optical beam over dimensions smaller than the minimum diffraction-limited spot size can be equivalent--and in some cases superior--to using multiple beamsplitters and discrete detectors that each sample a replica of the entire mode.
Proceedings Title: CQIQC III: Conference on Quantum Information and Quantum Control
Conference Dates: August 24-27, 2009
Conference Location: Toronto, -1
Pub Type: Conferences