Evolution of vortices created by conical diffraction in biaxial crystals versus orbital angular momentum

A Brenier (1)

1 ILM - Institut Lumière Matière [Villeurbanne]

Light states evolution versus their fractional orbital angular momentum (OAM) has been analyzed in the conical diffraction process occurring through biaxial crystals. Experimental results are provided by a non-degenerate cascade of KGd(WO2)4 and Bi2ZnOB2O6 biaxial crystals. The continuous 012 ℏ/photon increasing of the fractional OAM in passing through integer values was operated with the help of the spin-orbit coupling in the Bi2ZnOB2O6 crystal. The phase of the state light and its vortices were visualized by interference patterns with a reference beam. The evolution of the fractional OAM value is accompanied by a continuous evolution of pairs of vortices with opposite signs and linked by a-/+ discontinuous phase line. The phase pattern evolution around half-integer OAM is observed to be continuous. In other cases, the evolution can be interrupted by the breaking of a-/+ discontinuous phase line and a new pair of vortices with opposite charges is born.

Domains: Optics [physics.optics]; Quantum Physics [quant-ph]

A Brenier. Evolution of vortices created by conical diffraction in biaxial crystals versus orbital angular momentum. Optical Materials, 2020, ⟨10.1016/j.optmat.2020.110504⟩. ⟨hal-02976877v1⟩