Amplified Spontaneous Emissions from π-Conjugated Dye Doped Polymer Film and Silicate Optical Fiber

Yasuaki ITAKURA
Akihiro TOMIOKA
Shinji KINOSHITA
Atsushi FUJIMOTO

Publication
IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.12    pp.1746-1749
Publication Date: 2006/12/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.12.1746
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Towards the Realization of Organic Molecular Electronics)
Category: Evaluation of Organic Materials
Keyword: 
pi conjugated dye,  dye doped,  dye assembly,  polymer film,  photoluminescence,  

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Summary: 
We prepared transparent polymer films doped with π-conjugated organic dyes around a multimode silica fiber and observed very narrow fluorescence peaks as compared with the fluorescence in solution. The peak position showed no dependence on the excitation wavelength, indicating that it could not be explained by a whispering gallery mode in a medium with broad optical gain. The peaks can be explained by amplified spontaneous emissions (ASE) because the intensity depended linearly on the excitation intensity with a threshold. When the dye-doped film was formed on the portion of a fiber with the clad etched out and was excited by the polarized laser propagating inside the fiber core, we observed ASE peaks not of the dyes but of the optical fiber itself, suggesting the possibility that the dyes were oriented with their transition moment pointing parallel to the film surface. These fiber ASE peaks shifted to longer wavelength when we varied the excitation wavelength to shorter wavelength, which clearly ruled out the possibility of silicate Raman scattering as the origin.