Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

• Generation of vector beams using an off-the-shelf optical component, a double wedge depolarizer.
• Jones calculus to quantify the non-separability of the polarization and spatial mode parity degrees of freedom of the vector beam.
• Quantum-inspired concurrence and Bell-like inequality measurements are reported to quantify the degree of non-quantum entanglement of the optical beam.
• The generated vector beams are highly suitable for metrology applications and in logic gates and protocols appropriate for an entangling device and in photonic integrated circuits.

Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)–odd (Hermite–Gaussian) mode parity and horizontal–vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser–Horne–Shimony–Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.