Fig. 3: Boosting the Q0 via fine-polishing and heating.
From: Boosting silica micro-rod Q factor to 8.28 × 109 for fully stabilizing a soliton microcomb
a Scanning electron microscope (SEM) images of microcavity surface. b Atomic force microscope (AFM) images show a root-mean-square (RMS) roughness of 0.46 nm, and a surface inhomogeneity coefficient of 7.84 nm, after the fine polishing process. c Left: Ringdown curve of the microcavity after two-step polishing. Middle: The Q0 evolution during the heating, stable and recovery process. Right: Measured ringdown curve after heating process, showing that the intrinsic Q factor of the microcavity could be finally increased to 8.28 × 109. d Picture of the encapsulated device after heating, microrod inside keeps its Q0 higher than 7 × 109 level. e The proportions of various losses in the original, polished, and heated microcavity, respectively. Error bars: uncertainty in repeated measurements for 10 microcavity samples. f Improvement of the intrinsic Q factor from the original state to the final state after polishing and heating, here we record 10 microcavity samples.
