Dynamic functional metasurfaces at optical frequencies

Metasurfaces have been widely used in a variety of optical device applications due to their remarkable ability to modify the phase, amplitude and polarization of light.[1] Recently, switchable metasurfaces have attracted a lot... [ view full abstract ]

Metasurfaces have been widely used in a variety of optical device applications due to their remarkable ability to modify the phase, amplitude and polarization of light.[1] Recently, switchable metasurfaces have attracted a lot of attention due to their flexibility in controlling the optical fields at a designer’s wish. To achieve the switching functions, helicity multiplexed metasurfaces have been used to generate alternative holographic patterns through polarization control.[2] Interesting materials such as Ge₃Sb₂Te₆ have also been used to endow metasurfaces with switching functions.[3] However, so far a straightforward approach is missing to realize optical metasurfaces with versatile dynamic functions in a broad spectral range.

In this work, we demonstrate a novel approach to achieve dynamic functional metasurfaces at optical frequencies by employing the hydriding phase transition in magnesium (Mg).[4] Different optical functionalities can be dynamically switched upon hydrogenation/dehydrogenation of Mg metasurfaces without polarization manipulation. Our results show a great potential for metasurface applications in optical information encryption and provide a new route to design compact multifunctional optical devices.

References

[1]   Yu, N. et al. Light Propagation with phase discontinuities: generalized laws of reflection and refraction. Science 334, 333–337 (2011).

[2]   Wen, D. et al. Helicity multiplexed broadband metasurface holograms. Nat. Commun. 6, 8241 (2015).

[3]   Yin, X. et al. Beam switching and bifocal zoom lensing using active plasmonic metasurfaces. Light Sci. Appl. 6, e17016 (2017).

[4]   Duan, X. et al. Dynamic plasmonic colour display. Nat. Commun. 8, 14606 (2017).