Classical entanglement underpins the invariant propagation of space–time wave packets

H. Esat Kondakci (1) , Miguel Alonso (2, 3, 4, 5, 6) , Ayman Abouraddy (1)

1 CREOL - Center for Research and Education in Optics and Lasers
2 MOSAIC - MOSAIC
3 FRESNEL - Institut FRESNEL
4 ECM - École Centrale de Marseille
5 AMU - Aix Marseille Université
6 University of Rochester [USA]

Space-time wave packets are propagation-invariant pulsed beams that travel in free space without diffraction or dispersion by virtue of tight correlations introduced into their spatio-temporal spectrum. Such correlations constitute an embodiment of classical entanglement between continuous degrees of freedom. Using a measure of classical entanglement based on the Schmidt number of the field, we demonstrate theoretically and experimentally that the degree of classical entanglement determines the diffraction-free propagation distance of ST wave packets. Reduction in the degree of classical entanglement manifests itself in an increased uncertainty in the measured spatio-temporal spectral correlations

Domaines: Optique [physics.optics]

H. Esat Kondakci, Miguel Alonso, Ayman Abouraddy. Classical entanglement underpins the invariant propagation of space–time wave packets. Optics Letters, 2019, 44 (11), pp.2645. ⟨10.1364/OL.44.002645⟩. ⟨hal-02131496⟩