Photonic, Plasmonic, and Magnetically Coupled Responsive Photonic Crystals for New Sensing Strategies

Project: Research

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Photonic Crystals (PhC) attract great interest for a number of applications ranging from micro to nano pattering and lithography, sensors and light emission enhancement, amongst others. This is because they are easy to prepare, are cost-effective and can provide great versatility for their modification and functionalization. Coupling PhC with metals results in the hybrid plasmonic-photonic crystals (PlC) with a much enhanced optical response and functionality. Responsive photonic crystals (RPCs) are an important sub-class of PhC / PlC whose properties can be tuned externally, based on a stimulusresponse mechanism that must be coupled with the photonic crystal structure. We propose to investigate the use of magnetic-core nanospheres as versatile multifunctional model devices capable to dynamically couple photonic, plasmonic and magnetic effects to create multi-functional RPCs. Superparamagnetic, ~5 nm, Fe3O4, cores are embedded in larger, ~200-300 nm in diameter, dielectrics (PMMA, SiO2, TiO2, and others) spheres labeled magnetic-core dielectric nanospheres (mc-DNS) prepared on a metallic surface. In the proposed architecture, the temperature, and thus the size and refractive index of the mc-DNS can be controlled with a variable magnetic field. We will demonstrate the ability to follow these changes in real time using our group’s original strategy, namely use of spectroscopic ellipsometry (SE) and Finite Difference Tine-Domain method (SE-FDTD), which is well suited to correlate the expected changes with the effective refractive index changes in the device which will then be correlated to surface plasmon resonance (SPR) investigations.Finally, this approach will provide superb opportunities when applied to advanced SPR designs including bimetallic waveguide coupled surface plasmon resonance (Bi-WCSPR) and Fano-resonances (FR-SPR) because of additional effects such as multiple resonances and electromagnetic induced transparency provide enhanced sensitivity and additional reference points that can be used for sensing as a function of analyte concentration and applied magnetic field. In summary, this will take advantage of i) well-known strategies to assemble PhC to develop RPC based on magnetically induced thermal heating; ii) advanced SE-FDTD strategy developed by our group for quantitative optical characterization of the proposed devices; iii) sensing strategies based on advanced SPR designs; and ii) synergetic RPC capabilities and proposed SPR designs, to develop a novel two-scale reading sensor, akin to the use of a Vernier scale, to replace a single-measured value. This strategy will bring the use of PhC / PlC for point-of-care optical sensing in consumer products closer and will also find long-term applications for camouflage, security, antifraud devices and others. 


Project number9042881
Grant typeGRF
Effective start/end date1/01/20 → …