Organic photopumped semiconductor lases on flexible substrate
Visible-wavelength organic semiconductor lasers on a variety of substrates--including flexible plastic films--have lifetimes of at least several days (see Laser Focus World, May 1997, p. 151). Vladimir Kozlov of Princeton Optoelectronics Materials Center (Princeton, NJ) described the lasers at CLEO `97 in paper #CPD18. An amorphous film of organic material Alq3 [tris-(8-hydroxyquinoline) aluminum] doped with DCM laser dye emits red light (at about 665 nm) with a bandwidth of 3 nm, including 0.1-nm spikes from individual modes. The laser operated for three days at CLEO without measurable degradation. The 0.5-mm-long, 300-nm-thick layer of DCM:Alq3 emits peak output powers u¥to 30 W from a 3 ¥ 10-7-cm2 area on the edge when pumped by a UV nitrogen laser spot in a stripe across the surface. The laser material, developed for light-emitting diodes, was vacuum-deposited at room temperature. The edges follow the contours of the substrate, with roughness much less than the lasing wavelength, forming an optical cavity. The developers also demonstrated lasing from the material deposited on an overhead-projection transparency sheet and are working on electrical pumping.