Lasing from Epitaxially Oriented Needle Crystals of a Thiophene/Phenylene Co-Oligomer

Optically pumped lasing of epitaxially oriented molecular crystals is presented. Needle-like crystals of a thiophene/phenylene co-oligomer is grown along the [110] direction of a KCl substrate. The fluorescence light is one-dimensionally confined and amplified by the self-waveguiding effect in the elongated needles. The Fabry-Perot resonation by the terminated ends results in laser oscillations corresponding to the needle length.