Very compact tunable solid-state laser utilizing a thin-film organic semiconductor

Optically pumped organic semiconductor lasers are fabricated by evaporation of a thin film of tris(8-hydroxyquinoline) aluminum (Alq(3)) molecularly d oped with a laser dye on top of a polyester substrate with an embossed grat ing structure. We achieve low-threshold, longitudinally monomode distribute d-feedback laser operation. By varying the film thickness of the organic se miconductor film, we can tune the wavelength of the surface-emitting laser over 44 nm. The low laser threshold allows the use of a very compact ah-sol id-state pump laser (approximate to 10 cm long). This concept opens up a wa y to obtain inexpensive lasers that are tunable over the whole visible rang e. (C) 2001 Optical Society of America.