  Single photon emitters (SPEs) are critical building blocks needed for quantum
science and technology. For practical applications, large-scale
room-temperature solid-state platforms are required. Color centers in layered
hexagonal boron nitride (hBN) have recently been found to be ultra-bright and
stable SPEs at room temperature. Yet, to scale up solid-state quantum
information processing, large tuning range of single photon energy is demanded
for wavelength division multiplexing quantum key distribution, where
indistinguishability is not required, and for indistinguishable single-photon
production from multi-emitters. Stark effect can tune the single photon energy
by an electric field, which however, has been achieved only at cryogenic
temperature so far. Here we report the first room-temperature Stark effect of
SPEs by exploiting hBN color centers. Surprisingly, we observe a giant Stark
shift of single photon more than 30 meV, about one order of magnitude greater
than previously reported in color center emitters. Moreover, for the first
time, the orientation of the electric permanent dipole moment in the
solid-state SPE is determined via angle-resolved Stark effect, revealing the
intrinsic broken symmetries at such a color center. The remarkable Stark shift
discovered here and the significant advance in understanding its atomic
structure pave a way towards the scalable solid-state on-chip quantum
communication and computation at room temperature.
