We propose a single-photon spin-orbit entangled state analyzer for investigating the effective dimensionality of the Hilbert space spanned by spin and orbital angular momentum (OAM) states of twin photons from a spontaneous parametric downconversion (SPDC). The Pancharatnam–Berry phase element, the key element called a q plate equipped in the analyzer, induces the coupling between spin and OAM. It is found that the Shannon dimensionality of quantum channels in SPDC can be evidently increased owing to the spin-orbit hyperentanglement.
© 2009 Optical Society of America
Original Manuscript: April 13, 2009
Manuscript Accepted: May 11, 2009
Published: June 10, 2009
Lixiang Chen and Weilong She, "Increasing Shannon dimensionality by hyperentanglement of spin and fractional orbital angular momentum," Opt. Lett. 34, 1855-1857 (2009)