Who knew that spider silk, long studied for its tensile strength, could also act like an optical fiber?
Who knew that spider silk, long studied for its tensile strength, could also act like an optical fiber? French physicists are investigating its light-carrying properties for on-chip integration with other photonic structures. They presented their work at the Frontiers in Optics meeting in October.
Nolwenn Huby of the CNRS Institut de Physique de Rennes (France) and her group research the optical properties of the silk fiber spun by Nephila clavipes, a spider found in the warmer regions of North and South America. The female N. clavipes spins webs up to 1 m in diameter.
Huby’s group tested the light propagation ability of the 5-µm-wide fibers, which have a refractive index of about 1.55, and found attenuation of 20 ± 10 dB/cm. Next, the researchers verified the optical coupling of two silk fibers separated by a 15-µm gap.
Finally, the researchers used the silk to connect three disk reservoirs etched by UV lithography onto a silicon-based substrate. When they sent a laser beam through these structures, a microbeam profiler confirmed that they were properly coupled. The results hold great promise for future applications in biophotonics.