  An anisotropic quantum vacuum (AQV) has been predicted to induce quantum
interferences during the spontaneous emission process in an atomic
$V$-transition [G. S. Agarwal, Phys. Rev. Lett. 84, 5500 (2000)]. Nevertheless,
the finite lifetime of the excited states is expected to strongly limit the
observability of this phenomenon. In this paper, we predict that an AQV can
induce a long-lifetime coherence in an atomic $\Lambda$-transition from the
process of spontaneous emission, which has an additional advantage of removing
the need for coherent laser excitation. We also carry out two metasurface
designs and compare their respective efficiencies for creating an AQV over
remote distances. The detection of this coherence induced by a metasurface, in
addition to being yet another vindication of quantum electrodynamics, could
pave the way towards the remote distance control of coherent coupling between
quantum emitters, which is a key requirement to produce entanglement in quantum
technology applications.
