feed ical google calendar

(1) Presentation(s)


Mer. 05/04/2023 09:45 Bâtiment 20, Amphi

ACKEMANN Thorsten (University of Strathclyde, Glasgow)
Vector vortex solitons and spin-optoelectronics in vertical-cavity semiconductor lasers

(Physique de l'exciton, du photon et du spin)


Systems driven out of thermal equilibrium can form spontaneously complex structured spatial and spatio-temporal states via self-organization, even if the drive is homogeneous in space and constant in time. Broad-area vertical-cavity surface-emitting lasers (VCSELs) emerged as a highly controllable and versatile tool to investigate this interesting nonlinear laser dynamics as they are semiconductor lasers with very short (about 1 µm) but broad (about 200 µm diameter) microcavities. The high circular symmetry of VCSELs also allows for the polarization degrees of freedom to be self-organized. I will present investigations on the spontaneous appearance of vector vortex beams in a VCSEL with frequency-selective feedback with a radial, spiral and hyperbolic polarization structure and their interpretation as high order vectorial solitons. Vector vortex beams are an example of “fully structured light”, i.e. light beams with spatially inhomogeneous intensity and polarization distribution, usually created by specialized linear beam shaping devices. I will also review some results on mode-locking of laser cavity solitons, i.e. the possibility of spontaneous pulsations due to operating on multiple longitudinal modes. This might pave a path to “light bullets”, i.e. light self-localized in all three dimensions.

Evidence of spin memory for spin polarized pumping in the photoluminescence of quantum dot vertical-gain structures is presented. This opens the path to vertical-external cavity lasers with polarization control via pumping (“spin-VECSELs”).

Pour plus d'informations, merci de contacter Finco A.