Polarization squeezing and multipartite entanglement of triphoton states

Based upon standard angular momentum theory, we develop a framework to investigate polarization squeezing and multipartite entanglement of a quantum light field. Both mean polarization and variances of the Stokes parameters are obtained analytically, with which we study recent observation of triphoton states [L.K. Shalm et al., Nature 457, 67 (2009)]. Our results show that the appearance of the maximally entangled NOON state accompanied by (|3,0 >(H,V)-i|3,0 >(H,V))root 2, is a flip of mean polarization and can be well understood in terms of quantum Fisher information. (C) 2010 Optical Society of America