One- and two-photon pumped organic semiconductor lasers

Semiconductor lasers--Materials;Organic semiconductors;Optical pumping;Tunable lasers

Tsiminis, Georgios ; Turnbull, Graham A. ; Turnbull, Graham A.

University:University of St Andrews

Department:Physics & Astronomy (School of)

关键词: Semiconductor lasers--Materials;    Organic semiconductors;    Optical pumping;    Tunable lasers;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/927/Georgios%20Tsiminis%20PhD%20thesis.PDF?sequence=3&isAllowed=y

来源: DR-NTU

【 摘 要 】

This thesis describes a number of studies on organic semiconductors focusedaround using them as gain media for lasers. The photophysical properties oforganic semiconductors are studied using a wide range of experimentaltechniques, allowing the evaluation of new materials and novel excitationschemes for use in organic semiconductor lasers.Polyfluorene is a well-established conjugated polymer laser gain medium and inthis thesis its excellent lasing properties are combined with its two photonabsorption properties to demonstrate a tunable two-photon pumped solid-statelaser based on a commercially available organic semiconductor.A family of bisfluorene dendrimers was studied using a number ofphotophysical techniques to evaluate their potential as laser materials.Distributed feedback lasers based on one of the dendrimers are demonstratedwith lasing thresholds comparable to polyfluorene. The same materials werefound to have enhanced two-photon absorption properties in comparison topolyfluorene, leading to the fabrication of tunable two-photon pumpeddendrimer lasers.A member of a novel family of star-shaped oligofluorene truxenes wasevaluated as a laser gain material and the distributed feedback lasers made fromthem show some of the lowest lasing thresholds reported for organicsemiconductors, partly as a consequence of exceptionally low waveguide lossesin comparison to other single-material thin films.Finally, an organic laser dye is blended with a conjugated polymer, where thedye molecules harvest the excitation light of a GaN laser diode and transfer itsenergy to the polymer molecules. This is the first time such a scheme is used inan organic laser and in combination with a novel surface-emitting distributedBragg reflector resonator allows the demonstration of a diode-pumped organiclaser, a significant step towards simplifying organic lasers.