  We demonstrate fabrication of a high quality factor lithium niobate
double-disk whispering-gallery microcavity using femtosecond laser assisted ion
beam milling. Using this method, two vertically stacked 30-um-diameter disks
with a 200-nm-gap are fabricated. With our device, an optical quality factor as
high as 1.2*10^5 is demonstrated. Our approach is scalable to fabricate
multiple disks on a single chip.
