Seminários

Seminário do grupo de Óptica e Informação Quântica

Data: Sexta-Feira 21/09/2018, Sala A5-01, 11 am.

Palestrante: Daniel Tasca (UFF)

Título: How fast is a twisted photon?

Abstract:  Recent measurements have highlighted that even in vacuum spatially shaped photons travel slower than c, the speed of monochromatic plane waves. Here we investigate the intrinsic delay introduced by “twisting” a photon, i.e., by intro- ducing orbital angular momentum (OAM), and measure the photon time of flight with a Hong–Ou–Mandel inter- ferometer. When all other parameters are held constant, the addition of OAM reduces the delay (accelerates) with respect to the same beam with no OAM. We support our results using a theoretical method to calculate the group velocity and gain an intuitive understanding of the measured OAM acceleration by considering a geometrical ray-tracing approach.

https://doi.org/10.1364/OPTICA.5.000682