Nanooptics and photonics
Sensor features of resonant metal-dielectric multilayer nanostructure with P(VDF-TrFE) nonlinear layer
Lymarenko R.A.1, Ilchenko S.G.1,3, Bianco M.G. 2,
Pullano S.A.2, Fiorillo A.S.2
1 International Center “Institute of Applied Optics” National Academy of Science of Ukraine10G Kudryavska street, Kyiv, 04053, Ukraine.
E-mail:kit@iao.kiev.ua
2 Department of Health Sciences, University Magna Græcia of Catanzaro, 88100, Italy
3 Institute of Physics NAS of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine

Poly(vinylidenefluoride-trifluoroethylene) P(VDF-TrFE) copolymer with chemical formula (CH2-CFH)n is optically transparent, semi-crystalline piezoelectric polymer, which is mainly used in areas requiring excellent chemical resistance, high optical purity and excellent mechanical properties. P(VDF-TrFE) is a promising material for sensorics applications [1]. In this work we proposed to use this P(VDF-TrFE) film as last layer in resonant metal dielectric multilayer nanostructure [2]. The application of nanostructure with P(VDF-TrFE) in sensor is discussed. 
It consists of a metal nanolayer on prism and several pair of dielectric layers with high and low refractive index. The P(VDF-TrFE) formed relatively thick (about microns) layer. It is shown that adding such low refractive index layer leads to multiply the narrow minimum in angular distribution of reflectance. The detailed analysis of behavior and properties of resonance minima is given. The nonlinear properties of P(VDF-TrFE) and the high value of evanescent wave intensity at terminal layer give the opportunity to modulate the reflection coefficient by changing the resonant angle. The piezoelectric activity of P(VDF-TrFE) film allows to control the position of the minima. This feature can be useful for further improvement of SPR-like sensor. And otherwise, this structure can be applied as optical tactile sensor. Also, the low adhesive properties of P(VDF-TrFE) make this material suitable for last (contact) layer of sensor.

1.	Fiorillo A.S., Pullano S.A., Bianco M.G., Critello C.D. Bioinspired US sensor for broadband applications//Sens Actuators Phys.-2019.-294,-P. 148-153. 
2.	Ilchenko S. G., Lymarenko R. A., Taranenko V. B. Using Metal-Multilayer-Dielectric Structure to Increase Sensitivity of Surface Plasmon Resonance Sensor // Nanoscale Research Letters. -2017, -12, 295.