  Giant transmission and reflection of a finite bandwidth are shown to occur at
the same wavelength when the electromagnetic wave is incident on a periodic
array of PT-symmetric dimers embedded in a metallic film. Remarkably, we found
that this phenomenon vanishes if the metallic substrate is lossless while
keeping other parameters unchanged. When the metafilm is adjusted to the
vicinity of a spectral singularity, tuning substrate dissipation to a critical
value can lead to supper scattering in stark contrast to what would be expected
in conventional systems. The PT-synthetic plasmonic metafilm acts as a lasing
PT-spaser, a planar source of coherent radiation. The metallic dissipation
provides a mean to couple light out of the dark modes of the PT- spaser. Above
a critical gain-loss coupling, the metafilm behaves as a meta-gain medium with
the meta-gain atoms made from the PT-plasmonic dimers. This phenomenon implies
that super radiation is possible from a cavity having gain elements by tuning
the cavity dissipation to a critical value.
