Development of Photonic Multi-Sensing Systems Based on Molecular Gates Biorecognition and Plasmonic Sensors: The PHOTONGATE Project.

This paper presents the concept of a novel adaptable sensing solution currently being developed under the EU Commission-founded PHOTONGATE project. This concept will allow for the quantification of multiple analytes of the same or different nature (chemicals, metals, bacteria, etc.) in a single test with levels of sensitivity and selectivity at/or over those offered by current solutions. PHOTONGATE relies on two core technologies: a biochemical technology (molecular gates), which will confer the specificity and, therefore, the capability to be adaptable to the analyte of interest, and which, combined with porous substrates, will increase the sensitivity, and a photonic technology based on localized surface plasmonic resonance (LSPR) structures that serve as transducers for light interaction. Both technologies are in the micron range, facilitating the integration of multiple sensors within a small area (mm2). The concept will be developed for its application in health diagnosis and food safety sectors. It is thought of as an easy-to-use modular concept, which will consist of the sensing module, mainly of a microfluidics cartridge that will house the photonic sensor, and a platform for fluidic handling, optical interrogation, and signal processing. The platform will include a new optical concept, which is fully European Union Made, avoiding optical fibers and expensive optical components.

Near-field observation of beam steering in a photonic crystal superprism.

The optical near-field technique is applied to provide a direct experimental observation of the refracted beam propagation inside a photonic crystal structure displaying a superprism effect. The obtained results show a 35° light beam angle deviation for a wavelength variation from 1500 to 1600 nm. The experimentally determined beam divergence is in good agreement with modeling predictions and previously performed transmittance experiments. A marked self-collimation propagation over a broad 20 nm wide spectral range centered at λ=1550 nm is experimentally demonstrated. The developed technique opens promising perspectives for the invisibility cloaking structures investigation.

Compact, low cross-talk CWDM demultiplexer using photonic crystal superprism.

This paper addresses the problem of a photonic crystal (PhC) superprism design for coarse wavelength division multiplexing (CWDM) application. The proposed solution consists in using a PhC structure that presents an efficient balance between the wavelength dispersion and the beam divergence. It is shown that a bidimensional rhombohedral lattice PhC displays both a high beam collimation and an important wavelength dependant angular dispersion. We report the design, fabrication and experimental demonstration of a 4-channel optical demultiplexer with a spectral spacing of 25 nm and a cross-talk level of better than -16 dB using a 2800 microm(2) PhC region. The minimum of insertion losses of the demultiplexer is less than 2 dB. The obtained results present an important milestone toward PhC devices for practical applications.