  We report highly linearly polarized remote luminescence that emerges at the
cleaved edges of nanoscale gallium selenide slabs tens of micrometers away from
the optical excitation spot. The remote-edge luminescence (REL) measured in the
reflection geometry has a degree of linear polarization above 0.90, with
polarization orientation pointing toward the photoexcitation spot. The REL is
dominated by an index-guided optical mode that is linearly polarized along the
crystalline $c$-axis. This luminescence is from out-of-plane dipoles that are
converted from in-plane dipoles through a spin-flip process at the excitation
spot.
