mechanical systems.Fluorinated graphene; for example, is
transparent but also mechanically strong,90,91 so that it could
be a good material from which to build high-finesse optome-
chanical cavities.92 Other two-dimensional systems of inter-
est include h-BN, MoS2, and NbSe2, which are insulating,
semiconducting, and metallic, respectively.24,93,94 In general,
making mechanical devices out of single atomic layers opens
up a wide range of possibilities enabled by the low mass and
flexibility of these materials, while different materials will
enable tailoring of the optical and electrical properties of the
devices.Gra-
phene resonators have already proven that they can be manu-
factured in large arrays.