Ultrahigh spontaneous emission extraction efficiency induced by evanescent wave coupling
Résumé
A spontaneous emission extraction efficiency greater than 50% is observed in a GaAs/AlGaAs quantum well structure grown on the subwavelength-sized ridge top facet of a V-grooved substrate by means of photoluminescence study. This is an extraction efficiency about 20 times higher than that of a similar structure grown on a flat substrate. It is demonstrated both experimentally and theoretically that the high extraction efficiency is the result of the efficient conversion of evanescent waves into propagating waves in air through constructive coupling of evanescent waves generated on the two sidewall facets of the V-grooved substrate by total internal reflection.