Lasing at 460, 485, and 510 nm is demonstrated in optically pumped, vacuum-deposited amorphous thin films of a carbazole derivative doped with Coumarin 47, perylene, and Coumarin 30, respectively. Efficient, nonradiative Fo¨rster energy transfer between host and dopant organic molecules results in low lasing thresholds(5 &mgr;J/cm2),high differential quantum efficiencies (15&percent;), high peak output powers (20 W), and long operational lifetimes(>105pulses at 100 times the threshold power). ©1998 American Institute of Physics.