  Stimulated emission in small-molecule organic films at a high dye
concentration is generally hindered by fluorescence quenching, especially in
the red region of the spectrum. Here we demonstrate the achievement of high net
gains (up to 50 cm-1) around 640 nm in thermally evaporated non-doped films of
4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene, which makes this
material suitable for green-light pumped single-mode organic lasers with low
threshold and superior stability. Lasing effect is demonstrated in a DBR
resonator configuration, as well as under the form of random lasing at high
pump intensities.
