We report on the investigation and characterization of an optically tunable filtering effect, observed in a waveguide grating made of alternated strips of photocurable polymer and a mixture of azo-dye-doped liquid crystal. The grating is sandwiched between two borosilicate glasses, one of which includes an ion-exchanged channel waveguide, which confines the optical signal to be filtered. Exposure to a low power visible light beam modifies the azo-dye molecular configuration, thus allowing the filtered wavelength to be tuned over a 6.6 nm range. Simulations of the filtering response are well described with our experimental findings.
© 2011 Optical Society of America
Original Manuscript: September 29, 2011
Manuscript Accepted: October 18, 2011
Published: December 13, 2011
Giovanni Gilardi, Luciano De Sio, Romeo Beccherelli, Rita Asquini, Antonio d’Alessandro, and Cesare Umeton, "Observation of tunable optical filtering in photosensitive composite structures containing liquid crystals," Opt. Lett. 36, 4755-4757 (2011)