article posted 04 April 2016
Aaron Reupert currently is a PhD candidate at the Laboratory of Glass Science with Prof. Dr. Wondraczek where the focus of his
work is on the side emission of fibers. He holds a German diploma in physics from the Friedrich Schiller University of Jena and wrote his thesis and published
research on ion beam induced stress formation and relaxation in germanium.
Improving light emission performance of side emitting fibers with a fluorescent coating
Aaron Reupert*, Roland Wieg & Lothar Wondraczek
Otto Schott Institute of Materials Research, Friedrich Schiller University
Frauenhofer Straße 6, D-07743 Jena, Germany
The possibility of changing the emission pattern and wavelength of side emitting fibres (SEF) via application of a fluorescent dye layer was investigated. In the
context of light emission behavior of materials, the goal of optimal illumination implies lambertian light emission. So far, little research has been conducted on the
light emission of fibers and it remains unclear how to achieve lambertian light emission from these materials. Here, we apply a layer of fluorescent dye to the surface
of SEF to explore its potential effects on the fiber’s light emission behavior.
We conduct our experiment in the context of optimizing photosynthesis conditions in algae reactors and use commercially available multimode PMMA-fibers, modified for
dedicated light emission. The side emission intensity and pattern were measured with a microscope set-up.
The removal of the cladding and the roughening of the core resulted in a fiber with approx. constant attenuation and turned the PMMA-fiber into a side emitting fiber
with a preference for low emission angles (max. at ca. 30°) with respect to the fiber surface. Surprisingly, the application of dye also induced a more lambertian
emission pattern. This allows for two conclusions. First, it illustrates the possiblity of changing the wavelength of the side emitting light via a layer of fluorescent
dye on the fiber surface. Second, it shows that the emission pattern of the SEF, which normally is preferential for low emission angles, improves to a more lambertian
emission through applications of a luminescent dye.