Development of the waveguide photonic crystal structures formed by a distribution of nanoparticles in polymer matrix: Presentation held at 6th International Conference "Nanotechnologies and Nanomaterials", NANO 2018, 27.-30.08.2018, Kiyv, Ukraine

The goal of our work is to develop the waveguide photonic crystal (PC) structures formed by a distribution of nanoparticles (NPs) in polymer matrix for sensing applications. Development of sensors and structures for optical signal enhancement on the basis of polymers is currently of a high priority. We used original nanocomposites, in which PC structures with volume periodic modulation of permittivity are formed by holographic recording. We developed the improved theoretical model of resonance phenomena in waveguides with volume gratings. The theoretical investigations have predicted that such structures are characterized by a reflection coefficient close to unity and a spectral half-width of about 10-4 nm. The analysis of spectral characteristics of waveguide PC showed that the PC structures with a thickness of 1-2 μm would be optimal for sensing applications. We proposed and investigated three methods for the fabrication of thin (d ≤2 µm) photosensitive layers for further holographic structuring: a) spin-coating of nanocomposite deposited on a glass substrate; b) filling a cell consisting of two substrates with a capillary gap between them; and c) forming the layer between two substrates with help of a press with a controlled load. The final solid polymer layers were optically and topologically characterized. The results obtained indicate a sufficient uniformity of layer thicknesses and good surface quality. Holographic recording of the PC structures showed that in the indicated thickness range they provide the formation of periodic structures with a refractive index high contrast. In future it is planned to study the resonant properties of PC structures. The obtained results open perspectives to provide high sensitivity and selectivity of sensors based on volume periodic structures as well as to strengthen the fluorescence and the Raman scattering enhancement effects