  Molybdenum disulfide, $MoS_2$, is a next-generation semiconductor and is
frequently integrated into emergent optoelectronic technologies based on
two-dimensional materials. Here, we present a method that provides direct
optical feedback on the thickness and crystallinity of sputter-deposited
$MoS_2$ down to the few-layer regime. This smart sensing enables tracking the
material's functional properties, such as excitonic response, sheet resistance,
and hardness across the amorphous-crystalline transition. To illustrate the
potential of such feedback-controlled fabrication, we realized $MoS_2$-based
hyperbolic metamaterials (HMM) with controllable optical topological
transitions and hardness.
