  The gravitational deflection of massless and massive particles, both with and
without spin, has been extensively studied. This paper discusses the lensing of
a particle which oscillates between two interaction eigenstates. The deflection
angle, lens equation and time delay between images are derived in a model of
photon to hidden-photon oscillations. In the case of coherent oscillations, the
coupled photon behaves as a massive particle with a mass equal to the product
of the coupling constant and hidden photon mass. The conditions for observing
coherent photon-hidden photon lensing are discussed.
