Flexible photonic crystal membranes with nanoparticle high refractive index layers

Abstract

Flexible photonic crystal slabs with an area of 2 cm2 are 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 of Q ≈ 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.

Flexible and Stretchable Photonic Sensors Based on Modulation of Light Transmission

“…f) Spin coating high refractive index nanoparticles on periodically structured flexible and stretchable substrate. Reproduced with permission . Copyright 2017, Beilstein‐Institut.…”

“…Afterward, researches have used this method to fabricated flexible and stretchable photonic sensors. Karrock et al used the spin coating method to fabricate flexible photonic crystals based on ZnO and TiO 2 high refractive index layers . 10 wt% ZnO nanoparticles mixed with 0.5 wt% of fluorosurfactant was spin coated onto a periodically nanostructured hydrophilic poly(dimethylsiloxane)‐ b ‐poly(ethylene oxide) substrate.…”

“…With 6% applied strain, the peak resonance wavelength shifted 5.08% to red and 0.96% to blue from base peak resonance wavelength under different polarization of incident white light source. A strain sensor was fabricated by spin coating a layer of 95 nm thick TiO 2 nanoparticles on PDMS grating substrate, as can be seen from Figure c . The peak resonance wavelength kept red shifting as the applied strain was increased, as shown in Figure d.…”

Bioinspired Stimuli‐Responsive Color‐Changing Systems

“…Different concentrations of the TiO 2 nanoparticles result in different optical properties. Upon elongation up to 20% perpendicular to the grating direction, a 80 nm resonance shift is reported …”

Microcapsule‐Based Visualization Smart Sensors for Damage Detection: Principles and Applications

“…Visual sensors mainly include two types of film and microcapsule . The film visualization materials can only be applied to the surfaces as structural coatings . When the structure is subjected to external loads, the visualization film will produce the same deformation.…”