Probing High-Temperature Annealing Effects on Diamond Optical Microcavities

A critical step in the fabrication of solid-state qubits involves subjecting the host material to elevated temperatures, a process known as annealing. In the case of diamond, annealing not only facilitates the creation of color centers, but also determines their subsequent optical and spin properties. However, its effect on diamond optical cavities is not clearly understood. Here, we show that high-temperature high-vacuum annealing creates a surface layer on diamond microdisk devices that adversely affects their optical quality factors. We observed that this layer can be removed with an acid surface treatment that restores the optical properties of the microdisk resonators.