Realization of UV Plasmonic Nanolasers With Extremely Small Mode Volume

Abstract

It is difficult to operate plasmonic nanolasers on silver films in the ultraviolet regime owing to the bending-back effect of surface plasmon dispersion. In this paper, we report on plasmonic lasers comprised of a ZnO nanowire lying on a single-crystalline silver film with a SiO2 spacer layer. The silver can strongly shrink the mode volume, thereby boosting the Purcell factor. Meanwhile, the SiO2 spacer thickness is optimized to adjust the surface plasmon dispersion curve so that the lasing wavelength can be located at a large dispersion region, thereby achieving a large group index of 55, an ultra-small effective mode volume of 3.5 x 10(-3)lambda(3), and low-threshold of 11 MW/cm(2).