Treball final de màster oficial fet en col·laboració amb Universitat Autònoma de Barcelona (UAB), Universitat de Barcelona (UB) i Institut de Ciències Fotòniques (ICFO)

[ANGLÈS] Optical gap-nanoantennas are basic building blocks to control light at the nanoscale. We study how the morphology of the gap affects the response of the nanoantennas. A classical study shows that in spherical gaps the spectral position of the modes redshifts very strongly as the gap distance is reduced, whereas flat gaps present a saturation of the redshift. Moreover, flat-gap antennas show additional plasmon cavity modes that are not present in the far field, contrary to the spherical gaps where far-field and near-field spectra present the same set of modes. We analyze small gap distances where quantum effects need to be included in the description of the response due to electron tunneling. Using a Quantum Corrected Model, we show how tunneling can strongly modify the response. The near-field enhancement is strongly quenched as a consequence of tunneling and this effect depends strongly on the gap morphology. We also find that the spectral transition between non-touching and the overlapping regime for spherical-gap antennas dramatically changes in comparison with classical simulations.

[CASTELLÀ] Estudiamos los efectos de la morfología del gap en la respues optica de nanoantenas. Puesto que nos concentramos en gaps sub-nanometricos donde los efectos son mas importantees es necesario incluir el efecto del tunel quantico en el tratamiento. Hecho esto se estudian las grandes diferencias entre los resultados obtenidos a través de la teoría clasica con los obtenidos con las simulaciones cuanticas.