12 April 2005 Liquid crystal lasers: coherent and incoherent microsources
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Abstract
In this paper, we review our recent experimental work on coherent and incoherent liquid crystal lasers. For the coherent lasers, results are presented on thin-film photonic band edge lasing using dye-doped low molar mass liquid crystals in the self-organised chiral nematic phase. We show that potentially high Q-factor lasers can be fabricated from these materials by demonstrating that a single mode output with a very narrow linewidth is readily achievable in well-aligned monodomain samples. Moreover, from our investigations we have found that the performance of the laser, i.e. the slope efficiency and the excitation threshold, are dependent upon the physical parameters of the low molar mass liquid crystal. Specifically, the slope efficiency was found to vary from 1% to 12% depending upon the liquid crystalline material employed. Using this information, the important parameters of the host liquid crystal are highlighted. As regards to the functionality, we demonstrate how the wavelength of the laser can be tuned using an in-plane electric field in a direction perpendicular to the helix axis. Finally, for the incoherent lasers, we summarise our findings on random lasers that are fabricated from liquid crystals which exhibit a smectic A* phase.
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Stephen M. Morris, Stephen M. Morris, Alison D. Ford, Alison D. Ford, Benjamin J. Broughton, Benjamin J. Broughton, Mikhail N. Pivnenko, Mikhail N. Pivnenko, Harry J. Coles, Harry J. Coles, } "Liquid crystal lasers: coherent and incoherent microsources", Proc. SPIE 5741, Emerging Liquid Crystal Technologies, (12 April 2005); doi: 10.1117/12.626460; https://doi.org/10.1117/12.626460
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