Organic semiconductor laser

Summary form only given. Lasing action has been demonstrated in a vacuum-deposited 3000 /spl Aring/ thick layer of tris-(8-hydroxyquinoline)aluminum (Alq/sub 3/) doped with DCM laser dye. We observed a remarkably low lasing threshold at a pump energy density of 1 /spl mu/J/cm/sup 2/ with a 500 psec excitation pulse. Initial lifetime measurements showed an extremely high photochemical stability of the laser material. The low lasing threshold and high stability are primarily due to an excitation method in which pump light is absorbed by the host material (Alq/sub 3/), and the light emitting DCM molecules are excited by means of an efficient non-radiative energy transfer from the Alq/sub 3/ molecules. We also found that the facets of vacuum-deposited films are optically smooth, providing enough reflection for feedback. Hence, no processing of the material is necessary to fabricate a good optical cavity.