Abstract
In this letter, employing the spectroscopic ellipsometry, we study the phenomena of molecular reorientation in amorphous thin films of a ter(9,9-diarylfluorene) compound T3 upon annealing around or above its glass transition temperature. Molecular reorientation results in changes in the in-plane optical constants, which in turn could alter the waveguiding characteristics of a thin-film slab waveguide. Employing such properties, we demonstrate continuous tuning of the wavelength of amplified spontaneous emission of a T3 slab waveguide within one sample. Such an approach has the particular advantage of permitting facile tuning of stimulated emission after device fabrication. © 2005 American Institute of Physics.