Exploiting the natural instability in thin and flexible dielectric solid films for sensing and photonic applications – INVITED

¹ LENS and Department of Physics and Astronomy, University of Florence, Sesto Fiorentino, Italy
² Department of Physics, Politecnico di Milano, Milano, Italy
³ Aix Marseille Univ, Université de Toulon, CNRS, IM2NP Marseille, France
⁴ Institute of Chemical Sciences and Technologies (SCITEC) – CNR, Milano, Italy
⁵ Institute of Photonics and Nanotechnology (IFN) – CNR, Trento, Italy
⁶ Indivenire srl, Trento, Italy
⁷ Institute of Photonic and Nanotechnology (IFN)- Consiglio Nazionale delle Ricerche, LNESS laboratory, Como, Italy
⁸ Solnil, 95 Rue de la République, Marseille, 13002, France
⁹ Department of Information Engineering, University of Brescia, Brescia, Italy

^* Corresponding author: monica.bollani@ifn.cnr.it

Published online: 18 October 2023

Abstract

Flexible and stretchable photonics are emerging fields aiming to develop novel applications where the devices need to conform to uneven surfaces or whenever lightness and reduced thickness are major requirements. However, owing to the relatively small refractive index of transparent soft matter, these materials are not well adapted for light management at visible and near-infrared frequencies. Here we demonstrate simple, low cost and efficient protocols for fabricating Si_1−xGe_x-based, sub-micrometric dielectric antennas with ensuing hybrid integration into different plastic supports. The dielectric antennas are realized exploiting the natural instability of thin solid films to form regular patterns of monocrystalline atomically smooth silicon and germanium nanostructures. Efficient protocols for encapsulating them into flexible and transparent, organic supports are investigated and validated. We benchmark the optical quality of the antennas with light scattering measurements, demonstrating the control of the islands structural colour and the onset of sharp Mie modes after encapsulation.