Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 70: Semiconductor laser I: VECSEL and cascade lasers
HL 70.4: Vortrag
Mittwoch, 2. April 2014, 15:45–16:00, POT 112
Organic microlasers in vertical and lateral geometry — •Tim Wagner, Markas Sudzius, Andreas Mischok, Robert Brückner, Hartmut Fröb, and Karl Leo — Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Str. 1, 01069 Dresden
Optical microcavities can trap light in a very compact volume by different mechanisms, for example, by total internal reflection or distributed Bragg reflection. As a result, properties such as confinement, positive optical feedback, wavelength selectivity and outcoupling mechanisms are realized in entirely different ways.
In this work, we compare lasing characteristics of two conceptually different structures — vertical-cavity surface-emitting lasers and distributed feedback lasers — which are based on the same set of materials and technology. The active material in all structures is a blend of the red laser dye DCM doped by 2 wt% into the host material Alq3.
Although based on conceptually different microresonator structures, both devices show similar lasing thresholds Ith and comparable optical confinement factors β. A systematic analysis of these characteristics allows us to identify dominating mechanisms, which are responsible for the lasing thresholds, and let us justify the balance between the positive optical feedback, which is defined by the optical resonator, against the different kinds of optical losses. Based on the results obtained, devices combining concepts of VCSEL and DFB will be discussed further.