## Hardy’s nonlocality proof using twisted photons |

Optics Express, Vol. 20, Issue 19, pp. 21687-21692 (2012)

http://dx.doi.org/10.1364/OE.20.021687

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### Abstract

Hardy’s nonlocality proof is considered as “the best version of Bell’s theorem”. We report an experimental implementation of this by measuring the orbital angular momentum (OAM) of entangled twisted photon pairs. Two advantages arise from using twisted photons. First, the limited OAM spectrum generated by parametric down-conversion provides a natural set of OAM non-maximally entangled states with selective degrees of entanglement. Second, the measurement of any non-trivial superposition of OAM states can be conveniently done with spatial light modulators. We measure states that are defined on asymmetric OAM Bloch spheres and show results which are incompatible with local realism.

© 2012 OSA

**OCIS Codes**

(270.0270) Quantum optics : Quantum optics

(050.4865) Diffraction and gratings : Optical vortices

(270.5585) Quantum optics : Quantum information and processing

**ToC Category:**

Quantum Optics

**History**

Original Manuscript: June 28, 2012

Revised Manuscript: August 28, 2012

Manuscript Accepted: August 31, 2012

Published: September 6, 2012

**Citation**

Lixiang Chen and Jacquiline Romero, "Hardy’s nonlocality proof using twisted photons," Opt. Express **20**, 21687-21692 (2012)

http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-19-21687

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