Zhang Bo, Luo Cui-Bai

We propose a novel mechanism for photon-dark photon mass state oscillations mediated by gravitational separation during propagation through the interstellar medium. This phenomenon establishes a new avenue for the detection of dark matter. By analyzing gravitational lensing data from quasars, we investigate the sensitivity of this approach to dark photons. Our analysis demonstrates constraints of$\epsilon<10^-2$ in the dark photon mass range of $10^{-14}eV$. Furthermore, we propose potential applications of this mechanism to astrophysical systems with strong gravitational fields, such as neutron stars and black hole accretion disks.