  Realization of Quantum information and communications technologies requires
robust, stable solid state single photon sources. However, most existing
sources cease to function above cryogenic or room temperature due to thermal
ionization or strong phonon coupling which impede their emissive and quantum
properties. Here we present an efficient single photon source based on a defect
in a van der Waals crystal that is optically stable and operates at elevated
temperatures of up to 800 K. The quantum nature of the source and the photon
purity are maintained upon heating to 800 K and cooling back to room
temperature. Our report of a robust high temperature solid state single photon
source constitutes a significant step to-wards practical, integrated quantum
technologies for real-world environments.
