Hybrid nanodiamond and titanium dioxide nanobeam cavity design

Titanium dioxide is an emerging optical material, with a relatively high refractive index (n ~ 2), which allows for high confinement of the electromagnetic field. Extensive research has been conducted on the negatively charged nitrogen vacancy centre in diamond due to its robust electronic and optical properties. In particular, its stable room-temperature photoluminescence properties have been considered for quantum optical applications. Nanobeam cavities are a geometry that offer exceptionally large-Q values given their minimal footprint, a must for high density and compact optical architecture. This paper presents an ultrahigh-Q nanobeam cavity within titanium dioxide in a low-refractive index environment operating at the negatively charged nitrogen vacancy centre of diamond. This research opens the possibility of hybrid optical devices utilising titanium dioxide and diamond.