Realizing Q> 300 000 in diamond microdisks for optomechanics via etch optimization

摘要： Nanophotonic structures in single–crystal diamond (SCD) that simultaneously con?ne and co-localize photons and phonons are highly desirable for applications in quantum information science and optomechanics. Here we describe an optimized process for etching SCD microdisk structures designed for optomechanics applications. This process allows the optical quality factor, Q, of these devices to be enhanced by a factor of 4 over previous demonstrations to Q ～ 335 000, which is suf?cient to enable sideband resolved coherent cavity optomechanical experiments. Through analysis of optical loss and backscattering rates, we ?nd that Q remains limited by surface imperfections. We also describe a technique for altering microdisk pedestal geometry which could enable reductions in mechanical dissipation.