Nonlinear excitation of polariton cavity modes in ZnO single nanocombs

CAPELUTO, M.GABRIELA; GRINBLAT, GUSTAVO; TIRADO, MONICA; COMEDI, DAVID; BRAGAS, ANDREA V.

OPTICS EXPRESS

OPTICAL SOC AMER

Año: 2014 vol. 22 p. 5341 - 5349

1094-4087

Tunable second harmonic (SH) polaritons have been efficientlygenerated in ZnO nanocombs, when the material is excited close to half ofthe band-gap. The nonlinear signal couples to the nanocavity modes, and, asa result, Fabry-Pérot resonances with high Q factors of about 500 aredetected. Due to the low effective volume of the confined modes, matterlightinteraction is very much enhanced. This effect lowers the velocity ofthe SH polariton in the material by 50 times, and increases the SHconfinement inside the nanocavity due to this higher refractive index. Wealso show that the SH phase-matching condition is achieved through LOphononmediation. Finally, birrefringence of the crystal produces a strongSH intensity dependence on the input polarization, with a high polarizationcontrast, which could be used as a mechanism for light switching in thenanoscale.