Hamburg 2001 – scientific programme
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SYOF: Organische Festkörper
SYOF 5: Poster Session
SYOF 5.33: Poster
Tuesday, March 27, 2001, 17:00–19:00, Aula S3
A novel optically pumped polymer laser based on a circular grating structure — •C. Bauer1, H. Giessen1, B. Schnabel2, E.-B. Kley2, U. Scherf3, C. Schmitt4, and R. F. Mahrt1,4 — 1FB Physik, Philipps-Universität Marburg, 35032 Marburg — 2Institut für Angewandte Physik, Friedrich-Schiller Universität Jena, 07743 Jena — 3Institut für Physikalische und Theoretische Chemie, Universität Potsdam, 14476 Golm — 4MPI für Polymerforschung, 55128 Mainz
Conjugated polymers exhibit high optical gain which makes them promising candidates for organic solid state lasers. Future applications however, strongly require low lasing thresholds. Optimizing the photon confinement is one important goal in reducing the threshold. Since complete 3D confinement is usually difficult to achieve and modify, we used an idea new in the field of organic materials. The devices were fabricated as circular–grating surface–emitting distributed Bragg reflector lasers. A quartz substrate is nano–structured by electron-beam lithography resulting in a circular grating structure. A thin film of a ladder–type poly(p–phenylene) acts as emissive layer. The grating period is chosen to satisfy the second order Bragg condition. This results in a true 2D feedback within the plane of the polymer together with emission perpendicular to the sample surface via first order diffraction. Upon optical pumping our devices exhibit a clear threshold behavior, a highly directed emission beam, and a narrow spectral linewidth. Changing the grating period allows wavelength tuning of the lasers.