title: Observation of tunable optical filtering in photosensitive composite structures containing liquid crystals.
abstract: 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.
authors.affiliation: Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni, Sapienza Università di Roma, Rome, Italy. gilardi@die.uniroma1.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gilardi
authors.forename: Luciano
authors.initials: L
authors.lastname: De Sio
authors.forename: Romeo
authors.initials: R
authors.lastname: Beccherelli
authors.forename: Rita
authors.initials: R
authors.lastname: Asquini
authors.forename: Antonio
authors.initials: A
authors.lastname: d'Alessandro
authors.forename: Cesare
authors.initials: C
authors.lastname: Umeton