Journal
ADVANCED FUNCTIONAL MATERIALS
Volume 31, Issue 4, Pages -Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/adfm.202007210
Keywords
Ge2Sb2Te5; holography; metasurface; optical cryptography; phase-change material
Categories
Funding
- National Research Foundation of Korea (NRF) - Ministry of Science and ICT [2020R1A2B5B02002730, 2020R1A4A1019518]
- National Research Foundation of Korea [2020R1A2B5B02002730] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Ask authors/readers for more resources
This paper proposes a new method to expand the switching functionality of GST metasurfaces, and introduces a novel hologram technique for providing visually recognizable information in a specific state. This hybrid state is of significant importance for realizing highly secure visual cryptography architecture.
Chalcogenide material Ge2Sb2Te5(GST) has bistable phases, the so-called amorphous and crystalline phases that exhibit large refractive index contrast. It can be reversibly switched within a nanosecond time scale through applying thermal bias, especially optical or electrical pulse signals. Recently, GST has been exploited as an ingredient of all-optical dynamic metasurfaces, thanks to its ultrafast and efficient switching functionality. However, most of these devices provide only two-level switching functionality and this limitation hinders their application to diverse all-optical systems. In this paper, the method to expand switching functionality of GST metasurfaces to three level through engineering thermo-optically creatable hybrid state that is co-existing state of amorphous and crystalline GST-based meta-atoms is proposed. Furthermore, the novel hologram technique is introduced for providing the visual information that is only recognizable in the hybrid state GST metasurface. Thanks to thermo-optical complexity to make the hybrid state, the metasurface allows the realization of highly secured visual cryptography architecture without the complex optical setup. The phase-change metasurface based on multi-physical design has significant potential for applications such as all-optical image encryption, security, and anti-counterfeiting.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available