Optical and Near-infrared View of Planet-forming Disks and Protoplanets
  In this chapter of the Protostars and Planets VII, we review the breakthrough
progress that has been made in the field of high-resolution, high-contrast
optical and near-infrared imaging of planet-forming disks. These advancements
include the direct detection of protoplanets embedded in some disks, and
derived limits on planetary masses in others. Morphological substructures,
including: rings, spirals, arcs, and shadows, are seen in all imaged
infrared-bright disks to date, and are ubiquitous across spectral types. These
substructures are believed to be the result of disk evolution processes, and in
particular disk-planet interactions. Since small dust grains that scatter light
are tightly bound to the disk's gas, these observations closely trace disk
structures predicted by hydrodynamical models and serve as observational tests
of the predictions of planet formation theories. We argue that the results of
current and next-generation high-contrast imaging surveys will, when combined
with complementary data from ALMA, lead to a much deeper understanding of the
co-evolution of disks and planets, and the mechanisms by which planets form.
