  We numerically investigated the plane-wave reflection-transmission
characteristics of a columnar thin film (CTF) whose columns are made from a
dissipative material but whose void regions are filled with an active material.
By computing the reflectances and transmittances, we found that the CTF can
simultaneously amplify $s$-polarized incident light and attenuate $p$-polarized
incident light, or vice versa. This polarization-state-dependent attenuation
and amplification phenomenon depends upon the angle of incidence and the
thickness of the CTF.
