We present a simple device that works as a secondary source of light with prescribed polarization properties. The device has great versatility, allowing complete control over both the degree of polarization and the Stokes vector that belongs to the fully polarized component of partially polarized light beams. We report experimental results that illustrate the device’s versatility, by showing how polarized states can be moved within the Poincaré ball along spiraling paths.

We report robust polarimetric measurements of mixed-state geometric phases. An all-optical setup was used to generate geometric phases with great versatility, thereby extending the scope of analogous methods used in neutron polarimetry. Our method allows us to explore geometric phases generated by unitarily evolving mixed states. These are realized as partially polarized single-photon states whose degree of polarization and normalized Stokes vector can be fixed independently of one another. The geometric phases correspond to both open and closed trajectories in Poincaré space. By exploiting the gauge invariance of geometric phases we nullify their dynamical part, thereby making the geometric phase coincide with the total (Pancharatnam) phase, which can be directly addressed by employing standard techniques.

Propone un protocolo protegido de decoherencia para enviar estados cuánticos de fotones individuales a través de canales despolarizadores. Este protocolo se implementa a través de un sumador cuántico aproximado diseñado a través de convertidores paramétricos descendentes espontáneos, y muestra una mayor probabilidad de éxito que los protocolos de teletransportación cuántica destilada para distancias por debajo de un umbral dependiendo de las propiedades del canal.

CONCYTEC-FONDECYT (Grant-Nr. 233-2015); CONCYTEC-FONDECYT (Grant-Nr. 236-2015); DGI-PUCP (Grant-Nr. 441).