Fig. 3: Nanophotonic integration with direct-bonded membranes.
From: Direct-bonded diamond membranes for heterogeneous quantum and electronic technologies
a Schematics of TiO2-based (top) and diamond-based (bottom) nanophotonics on diamond membrane heterostructures. In this work fused silica (thermal oxide silicon) wafers are used as carrier wafers for the TiO2 (diamond)-based demonstrations. The grating couplers for excitation (collection) are colored in red (blue), respectively. b Microscope images of TiO2 fishbone cavities and ring resonators on a 50 nm-thick diamond membrane. Images were taken at the same location but different fabrication rounds. c The transmission spectrum of a fishbone cavity with resonant frequency at 737.26 nm. Inset: the transmission of the cavity with a tunable laser as the excitation source, showing a quality factor Q of 10640 ± 118. d The bright field and dark field microscope images of the ICP-etched diamond ring resonators on a thermal oxide silicon substrate, showing great uniformity with minimal process contamination. e The transmission spectrum of the diamond-based ring resonator measured at the drop port. Insets: the TE mode profile, and the TE cavity resonance with a quality factor QTE of 21883 ± 6284. The fluctuation in the right inset is caused by the instability of the optical setup.
