  We investigate spontaneous emission from a quantum emitter located within the
mode volume of a microring resonator that features chiral exceptional points.
We show that this configuration offers enough degrees of freedom to exhibit a
full control to either enhance or suppress the emission process. Particularly,
we demonstrate that the Purcell factor can be enhanced by a factor of two
beyond its value in an identical microring operating at a diabolic point. Our
conclusions, which are derived using a non-Hermitian Hamiltonian formalism, are
confirmed by employing full-wave simulations of realistic photonic structures
and materials. Our results offer a straightforward route to improve the
performance of single photon sources using current photonics technology without
the need for building optical resonators with ultrahigh quality factors or
nanoscale volumes.
