Conditions for one- and two-band lasing in organic dyes embedded in polymer hosts

The range of one- and two-band lasing in a donor-acceptor system of polymer laser elements is determined for a fixed donor concentration and a varying acceptor concentration. The calculations are made assuming longitudinal pulsed coherent pumping of the donor dye and a radiative mechanism for transfer of electronic excitation energy from the donor to the acceptor. Expressions are derived for the lasing threshold of the system in the fluorescence bands of the donor and the acceptor. The calculated range of one- and two-band lasing in the system of laser dyes was confirmed experimentally.