Flexible photonic crystal membranes with nanoparticle high refractive index layers.

Flexible photonic crystal slabs with an area of 2 cm 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 ≈ 40 are observed.

Pressure sensor based on flexible photonic crystal membrane.

We demonstrate a pressure sensor based on deformation of a periodically nanostructured Bragg grating waveguide on a flexible 50 µm polydimethylsiloxane membrane and remote optical read out. A pressure change causes deformation of this 2 mm diameter photonic crystal membrane sealing a reference volume. The resulting shift of the guided mode resonances is observed by a remote camera as localized color change.

Handheld imaging photonic crystal biosensor for multiplexed, label-free protein detection.

We present a handheld biosensor system for the label-free and specific multiplexed detection of several biomarkers employing a spectrometer-free imaging measurement system. A photonic crystal surface functionalized with multiple specific ligands forms the optical transducer. The photonic crystal slab is fabricated on a glass substrate by replicating a periodic grating master stamp with a period of 370 nm into a photoresist via nanoimprint lithography and deposition of a 70-nm titanium dioxide layer.

Enhanced sensitivity of photonic crystal slab transducers by oblique-angle layer deposition.

Photonic crystal slabs (PCS) are one of the major transducers for label-free, optical biosensing applications. In this paper we present oblique-angle layer deposition of the high index slab material as a method to improve the PCS sensitivity. In simulations and experiments we consider PCSs composed of a high index silicon monoxide layer on a nanostructured resist layer on a glass substrate.

Visual device for pressure measurement using photonic crystal slabs.

We propose and demonstrate a visual, all-optical pressure-measuring device composed of a flexible membrane dilating toward a photonic crystal slab. Due to its transparency and capability to be miniaturized, it may be integrated on the inner side of an artificial lens and directly measure the eye's intraocular pressure. Using crossed polarization filters for the readout process, we obtain a contrast enhancement for the circular contact area of the membrane with the photonic crystal slab.