Shining massive light through a wall

A massive photon possesses a longitudinal polarization mode absent in its massless counterpart. Transverse and modes follow different dispersion relations, the latter being much less attenuated than former when passing through conductor, suggesting possibility of isolating by shining intense light on conducting wall. We calculate transmission rates for normal incidence upon semi-infinite medium passage slab. For second case we compare expected fluxes with those measurable current future light-shining-through-a-wall experiments. Using 1-MW microwave source as envisaged STAX project, sensitivity at level $m_\gamma < 9.6 \times 10^{-11} \, {\rm eV/c^2}$ could be reached after run time an year, potential improvement factor $\sim 10^4$ if radio waves similar power are used.