Polarization dependent thresholds of a polymer laser

Summary form only given. Almost all lasers emit light with a well-defined polarization. The direction of this polarization is determined by dichroic and birefringent properties of the complete laser, i.e., of both the cavity and the active medium. In optically pumped lasers one has access to the dichroism and/or birefringence of the gain medium through, for instance, the polarization of the optical pump beam. We have used the anisotropy of light-emitting polymer solutions to build a short-cavity laser whose output characteristics are strongly dependent on the pump polarization. Inside a 25 mm long laser cavity we transversally pump the polymer solution with a 100 fs long pulse at 400 nm focussed to a line on the cavity axis.