Self-Assembled Glass Based and Plasmonic Metasurface by Controlled Fluid Instability

Modern devices require the tuning of the size, shape and spatial arrangement of nano- objects and their assemblies with nanometer scale precision, over large-area and sometimes soft substrates. Such stringent multi-scale and mechanical requirements are beyond the reach of conventional lithography techniques or simpler self-assembly approaches. In this talk, at first we will demonstrate an unprecedented control over the fluid instabilities of thin glass films as a simple approach for the self-assembly of advanced all-dielectric metasurfaces. We show and model the tailoring of the position, shape, size and inter-particle distance of nano-objects with feature sizes below ten nanometers [1]. This simple and versatile approach can generate optical nanostructures over tens-of-centimeters sized rigid and soft substrates, with better optical performance and a resolution on par with advanced lithography-based processes. By a programmable control of the nanoimprinting method and the initial film thickness we show that we can achieve tunable particle size and lattice using the same master Silicon mold. To underline the potential of our approach, we demonstrate various optical phenomenons like a mechanochromic sensor, second harmonic generation with conversion efficiency as high as 10^-6, and a Fano resonance with a highest Quality Factor ~300 in visible to date [2]. Lastly, we show by tuning just the substrate softness Gallium based liquid metals [3] for the first time could be used as a dynamic metasurface where the optical properties could be tuned in-situ by applying a simple mechanical stress.<br/>References:<br/>[1] T. Das Gupta et al. Nature nanotechnology, 2019<br/>[2] T. Das Gupta et al. Nanophotonics, 2021<br/>[3] L.Martin, T. Das Gupta et al. Adv. Functional Materials, 2021