Excitonic laser action

PM spectra and their decays in DOO-PPV films and dilute solutions, we conclude that the primary excitations in DOO-PPV films are also singlet excitons [26]. The long excitonic lifetime and a corresponding high PL quantum efficiency [27] indicates that DOO-PPV is a high quality polymer material, which is very suitable for electrooptics and laser action applications [28],... 

Ultrafast Exciton Dynamics and Laser Action in n-Conjugated Semiconductors... 

It is apparent that the right-hand side of Equation 22.22 contains two driving terms, which correspond to the macroscopic dipole moment of the excitons (St) and their radiated electromagnetic field (At), respectively. The first term gives rise to cooperative radiation or SF, whereas the second term is the source of ASE. It thus becomes clear that, in general the resultant laser action emission contains contributions from both SF and ASE. Whether the laser action emission is dominated by SF or ASE is determined within this model by the values of kt and T2. Here, is the Arrechi-Courtens cooperation time [112] given by = b crN/V). The value of accounts for the number of photons emitted by the... 

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