2005/11/30 by Fang‐Wen Sun, F. W. Sun, Z. Y. Ou +2 · 1 citation
Computer Science · Physics and Astronomy · #Orbital Angular Momentum in Optics #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1103/physreva.73.023808
8 pages, 3 figures, new title, some content change, replaced Fig.1
arxiv created 2005/12/11 · openalex publication_date 2006/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We construct a projection measurement process for the maximally entangled N-photon state [the NOON state (\ensuremath|N,0⟩+\ensuremath|0,N⟩)∕√(2)] with only linear optical elements and photodetectors. This measurement process will give null result for any N-photon state that is orthogonal to the NOON state. We examine the projection process in more detail for N=4 by applying it to a four-photon state from type-II parametric down-conversion. This demonstrates an orthogonal projection measurement with a null result. This null result corresponds to a dip in a generalized Hong-Ou-Mandel interferometer for four photons. We find that the depth of the dip in this arrangement can be used to distinguish a genuine entangled four-photon state from two separate pairs of photons. We next apply the NOON state projection measurement to a four-photon superposition state from two perpendicularly oriented type-I parametric down-conversion processes. A successful NOON state projection is demonstrated with the appearance of the four-photon de Broglie wavelength in the interference fringe pattern.