Optical metasurfaces, composed of planar arrays of sub-wavelength dielectric or metallic structures that collectively mimic the operation of conventional optical elements, have revolutionized the field of optics by their potential in constructing high-efficiency and multi-functional optoelectronic systems with a compact form factor. The study of metasurface now spans various multidisciplinary fields in both fundamental research on light-matter interaction, and emerging applications from solid-state LiDAR to compact imaging and spectroscopy devices. The goal of this focus session is to explore both novel physics and diverse applications of optical metasurfaces operating from the microwave to the ultraviolet spectral range.