RI-IWEAR Research Seminar XVIII (只有英文版本)

Topic: Innovative fabrication approaches for soft optical metasurfaces, advanced multi-material fibers and smart textiles

By Prof. Fabien Sorin

The ability to realize advanced photonics systems on soft and deformable substrates can find tremendous opportunities in sensing and monitoring, health-care, soft robotics and smart textiles. The materials and processing challenges associated with imparting large, flexible and stretchable surfaces with state-of-the-art photonic performance remain however significant. In this talk, I will present novel fabrication strategies that we have been developing that rely on understanding and controlling viscous flow at various scales, from the fluid dynamics of optical fiber thermal drawing, to the nano-fluidics associated with thin-film dewetting^1-7. Both approaches, while seemingly very different, exhibit an interesting interplay between viscosity and surface tension, that can be elucidated via in-depth rheological analysis, thermomechanical characterization, and fluid dynamics modeling. First, I will present the template dewetting of thin optical glass layers on textured flexible and stretchable substrates as a novel approach to realize advanced optical metasurfaces on stretchable substrates^2,4. Examples of structures and applications will include index and biosensing, and second-harmonic generation. I will then make a parallel with thermal drawing, the fabrication process used to make optical fibers. I will show that an in-depth analysis of the rheological, thermomechanical and fluid dynamic aspects of this technique reveal similar features as dewetting, and has expanded the range of materials compatible with this approach. I will insist in particular on the recent ability to draw thermoplastic elastomers¹, metallic glasses³, as well as of complex and multi-functional optical fiber architectures with either mechanical⁵ or magnetic6 actuation. I will also present recent results in the thermal drawing of liquid metal and liquid-metal composites. These advances in materials an processing is paving the way towards advanced state-of-the art soft optics systems with multi-functionalities for applications in surgical diagnosis and intervention, wearable, soft robotics, bio-sensing and smart textiles.

References: [1] Advanced Materials 30, 1707251 (2018) ; [2] Nature Nanotechnology 14, 320 (2019); [3] Nature Nanotechnology 15, 875 (2020); [4] Nanophotonics 10, 3465 (2021); [5] Advanced Science 10, 2204016 (2023); [6] Advanced Materials 202212202 (2023). [7] National Science Review 11, nwae290 (2024).