Optical manipulation of quantum fluids in semiconductor microcavities
- Autores: Guilherme Tosi
- Directores de la Tesis: Luis Viña (dir. tes.)
- Lectura: En la Universidad Autónoma de Madrid ( España ) en 2013
- Idioma: inglés
- Tribunal Calificador de la Tesis: José Manuel Calleja Pardo (presid.), Carlos Tejedor (secret.), Andrés Cantarero (voc.), Luisa González Sotos (voc.), Jacqueline Bloch (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: Biblos-e Archivo
- Resumen
When semiconductor materials are properly nano-structured, as to allow for excitons and photons to coherently interact for long enough times, a new quasi-particle emerges called polariton. These mixed light-matter entities inherit the bosonic character from their constituents: under high densities, polaritons occupy a single macroscopic state. Their collective coherent flow can be easily manipulated and visualised by using simple opticalmicroscopy configurations. Despite their macroscopic size, polariton fluids have different properties from those of classical fluids: the laws of quantum mechanics are directly observed at macroscopic scales. As we show in this thesis, the angular momentum of a polariton vortex assumes quantised values, differently from classical vortices. Moreover, the circular currents of a stirred polariton fluid persist with no apparent dissipation. We also show that an outflowing polariton liquid propagate ballistically, differently from water ripples. We unveil new polaritonic phenomena that are very different from the ones of equilibrium quantum fluids: polariton out-of-equilibrium currents are capable of generating unintended vortex-antivortex pairs and determine new conditions for the stability of doubly-quantised circulation. It is also possible to shape the polariton flow pattern in such a way that interferences generate stable vortex lattices. Finally, we show that polariton interactions are so strong as to shape its own confining potential, generating harmonically-oscillating fluid packets.
