Compact design of a gallium phosphide nanobeam cavity for coupling to diamond germanium-vacancy centers

A design for an ultrahigh Q/V nanobeam cavity engineered to interact with Germanium-vacancy (GeV) centers is presented. The nanobeam cavity supports a mode with Q/V > 10(8) with transmission over 70%. The proposed design is based on a new scalable approach developed to reduce the footprint of nanobeam cavities by more than 50% without losing the cavity Q/V value and transmission. Cavity quantum electrodynamics analysis reveals that strong coupling between the zero-phonon line transition of GeV centers and the cavity mode can be achieved for a range of nanobeam dimensions. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement