First observation of DFB lasing in polarization gratings written in azobenzene film

For the first time the fabrication of DFB laser devices based on polarization gratings in azobenzene-containing materials has been exploited. The gratings were inscribed by polarization holography in a layer of an azobenzene oligomer doped with a fluorophore (laser dye pyridine 1 or pyridine 2). The single step inscription of a polarization grating in this layer leads directly to a DFB laser device. The devices exhibited a lasing threshold of about 0.2–0.3 mJ cm−2. (letter)