title: Flexible photonic crystal membranes with nanoparticle high refractive index layers.
abstract: Flexible photonic crystal slabs with an area of 2 cm2are fabricated by nanoimprint replication of a 400 nm period linear grating nanostructure into a ≈60 µm thick polydimethylsiloxane membrane and subsequent spin coating of a high refractive index titanium dioxide nanoparticle layer. Samples are prepared with different nanoparticle concentrations. Guided-mode resonances with a quality factor ofQ≈ 40 are observed. The highly flexible nature of the membranes allows for stretching of up to 20% elongation. Resonance peak positions for unstretched samples vary from 555 to 630 nm depending on the particle concentration. Stretching results in a resonance shift for these peaks of up to ≈80 nm, i.e., 3.9 nm per % strain. The color impression of the samples observed with crossed-polarization filters changes from the green to the red regime. The high tunability renders these membranes promising for both tunable optical devices as well as visualization devices.
authors.affiliation: Institute of Electrical Engineering and Information Technology, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, Kiel, 24143, Germany.
authors.forename: Torben
authors.initials: T
authors.lastname: Karrock
authors.affiliation: Institute of Electrical Engineering and Information Technology, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, Kiel, 24143, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Paulsen
authors.affiliation: Institute of Electrical Engineering and Information Technology, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, Kiel, 24143, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Gerken
keywords: fabrication; flexible membrane; nanostructure; photonic crystal; resonance shift