Hybrid gap plasmon GaAs nanolasers

Abstract

Compact semiconductor lasers with sub-wavelength-scale dimensions rely heavily on materials with low surface recombination due to the large surface area to volume ratios of their nano-cavities. Furthermore, the reliance on semiconductor nanostructures has led to predominantly bottom-up fabrication approaches, which has hindered scalable and practical applications. In this letter, we present lithographically constructed hybrid gap plasmon nanolasers using the gain of bulk GaAs operating at room temperature. The nanolasers are built on GaAs suspended membranes with InGaP passivation layers. Laser resonators are defined only by patterning gold on top of these GaAs membranes, thus eliminating the need to etch the semiconductor for optical confinement, which would introduce additional surface recombination. An analysis of the modal gain and losses in these devices suggests that threshold carrier densities in the range of 4-5×1018 cm-3 are necessary - potentially achievable with current densities as low as 6-8 kA cm-2.