Threshold current analysis of distributed feed-back organic semiconductor lasers

The relationship between the exciton density and material gain in an Alq(3):DCM organic semiconductor laser material is estimated by a comparison between published experimental data and the results of a static analysis of organic semiconductor distributed feedback lasers. The gain coefficient for an Alq(3):DCM laser material operating at 640 nm is estimated to be of order 1 x 10(-18) cm(2). This value is used to perform a threshold current optimisation of a double heterostructure (DH) organic semiconductor laser utilising a substrate grating for distributed feedback. It is found that the threshold current density can be reduced by approximately 35% by such an optimisation. The minimum threshold current density for a 2 cm long device is estimated to be about 50A cm(-2.)