  Atomic-scale control of light-matter interactions represent the ultimate
frontier for many applications in photonics and quantum technology.
Two-dimensional semiconductors, including transition metal dichalcogenides, are
a promising platform to achieve such control due to the combination of an
atomically thin geometry and convenient photophysical properties. Here, we
demonstrate that a variety of durable polymorphic structures can be combined to
generate additional optical resonances beyond the standard excitons. We
theoretically predict and experimentally show that atomic-sized patches of 1T
phase within the 1H matrix form unique electronic bands that give rise to new
and robust optical resonances with strong absorption, circularly polarized
emission and long radiative lifetime. The atomic manipulation of
two-dimensional semiconductors opens unexplored scenarios for light harvesting
devices and exciton-based photonics.
