  Active optical metasurfaces are rapidly emerging as a major frontier in
photonics research, development, and commercialization. They promise compact,
light-weight, and energy-efficient reconfigurable optical systems with
unprecedented performance and functions that can be dynamically defined
on-demand. Compared to their passive counterparts, the reconfiguration capacity
of active metasurfaces also set additional challenges in scalable design,
manufacturing, and control toward their practical deployment. This perspective
aims to review the state-of-the-art of active metasurface technologies and
their applications while highlighting key research advances essential to
enabling their transition from laboratory curiosity to commercial reality.
