Triangular nanobeam photonic cavities in single- crystal diamond

Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multiqubit computing. Here, we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel nanobeam cavity produced in a single crystal diamond are demonstrated. The present cavity design, based on a triangular cross-section, allows vertical confinement and better signal collection efficiency than that of slab-based nanocavities and eliminates the need for a pre-existing membrane. The nanobeam is fabricated by focused-ion-beam (FIB) patterning. The cavity is characterized by confocal photoluminescence. The modes display quality factors of Q ∼ 220 and deviate in wavelength by only∼1.7 nm from the nitrogen-vacancy (NV) color center zero phonon line (ZPL). The measured results are found to be in good agreement with three-dimensional finite-difference-time-domain (FDTD) calculations. A more advanced cavity design with Q = 22 000 is modeled, showing the potential for high-Q implementations using the triangular geometry. The prospects of this concept and its application in spin non-demolition measurement and quantum computing are discussed. 3 Author to whom any correspondence should be addressed. New Journal of Physics 13 (2011) 025018 1367-2630/11/025018+13$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft