Nanooptics and photonics
Hyperbolic plasmons at resonant anisotropic metasurfaces
Yermakov O.Y.1,2
1 Department of Computer Physics, V. N. Karazin Kharkiv National University, 61022, 4 Svobody Square, Kharkiv, Ukraine.
2 School of Physics and Engineering, ITMO University, 
197101, 49 Kronverksky avenue, St. Petersburg, Russian Federation.
E-mail: oe.yermakov@gmail.com 

This work presents the results of theoretical and experimental studies and control of the properties (dispersion, polarization, phase and spatial distribution, directivity, optical spin) of surface electromagnetic waves localized on anisotropic resonant metasurfaces in the optical, near-infrared and microwave ranges. 
Namely, we study the localized eigenmodes spectrum of the resonant anisotropic metasurfaces through the developed effective surface conductivity approach [1,2]. We discover new type of surface waves at the metasurfaces with hyperbolic dispersion, known today as ‘hyperbolic plasmon-polaritons’, which exhibit a number of propagation regimes [1,3,4]. Besides, we investigate tunable polarization control of surface waves localized at anisotropic metasurfaces, in particular, we engineer the orientation of the spin angular momentum on demand in the near-field and discover the polarization degree of freedom for localized light [4,5]. The theoretical results of surface waves investigation have been confirmed experimentally in the optical, near-infrared [2,3] and microwave [4] frequency ranges. To conclude, we consider this work as a significant milestone towards the development of planar photonic and flat-optics devices.

1.	Yermakov O. Y. et al. Hybrid waves localized at hyperbolic metasurfaces // Phys. Rev. B. – 2015. – 91. – №. 23. – P. 235423.
2.	Yermakov O. Y. et al. Effective surface conductivity of optical hyperbolic metasurfaces: from far-field characterization to surface wave analysis // Sci. Rep. – 2018. – 8. – P. 14135.
3.	Samusev A. et al. Polarization-resolved characterization of plasmon waves supported by an anisotropic metasurface // Opt. Express. – 2017. – 25. – №. 26. – P. 32631-32639.
4.	Yermakov O. Y. et al. Experimental observation of hybrid TE-TM polarized surface waves supported by a hyperbolic metasurface // Phys. Rev. B. – 2018. – 98. – №. 19. – P. 195404.
5.	Yermakov O. Y. et al. Spin control of light with hyperbolic metasurfaces // Phys. Rev. B. – 2016. – 94. – №. 7. – P. 075446.