Varifocal Metalens Using Tunable and Ultralow-loss Dielectrics.
Adv Sci (Weinh)
; 10(6): e2204899, 2023 Feb.
Article
in En
| MEDLINE
| ID: mdl-36596668
ABSTRACT
The field of flat optics that uses nanostructured, so-called metasurfaces, has seen remarkable progress over the last decade. Chalcogenide phase-change materials (PCMs) offer a promising platform for realizing reconfigurable metasurfaces, as their optical properties can be reversibly tuned. Yet, demonstrations of phase-change metalenses to date have employed material compositions such as Ge2 Sb2 Te5 , which show high absorption in the visible to near-IR wavelengths particularly in their crystalline state, limiting the applicability. Here, by using a low-loss PCM Sb2 Se3 , for the first time, active polarization-insensitive phase-change metalenses at near-IR wavelengths with comparable efficiencies in both material states are shown. An active metalens with a tunable focusing intensity of 95% and a focusing efficiency of 23% is demonstrated. A varifocal metalens is then demonstrated with a tunable focal length from 41 to 123 µm with comparable focusing efficiency (5.7% and 3%). The ultralow-loss nature of the material introduces exciting new possibilities for optical communications, multi-depth imaging, beam steering, optical routing, and holography.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Adv Sci (Weinh)
Year:
2023
Document type:
Article
Affiliation country:
United kingdom