“Biologically Inspired Soft and Fluid Optical Materials”
Mathias Kolle
Department of Mechanical Engineering,
Massachusetts Institute of Technology
77 Massachusetts Ave, Cambridge MA-02139, US
Abstract
A curious look at biological photonic systems reveals a myriad of versatile approaches for the creation of multifunctional, hierarchically structured, dynamic bio-inspired materials. Here, we present a choice of materials that employ bio-inspired photonic architectures, implemented in soft, and fluid materials, with tunable and stimuli-responsive behavior.
The first part of this presentation will be focused on elastic, mechano-sensitive, colortunable bio-inspired photonic fibers, which mimic the photonic structures found in a tropical plant’s blue seed coat. The fibers consist of an elastomeric multilayer cladding, rolled onto a stretchable core. Their reflection color can be tuned reversibly by applying an axial strain or a lateral compression. This effect persists even after several thousand deformation cycles. We demonstrate potential applications for mechano-responsive, color-tunable photonic fibers in medical sensing.
In the second part, we explore the use of emulsions for the creation of liquid compound micro-lenses with dynamically tunable focal lengths, inspired by the architectures found in the retina of nocturnal animals. We employ bi-phase emulsion droplets in responsive microlenses that can be reconfigured to focus or scatter light, and to form images. We provide evidence of the micro-lenses’ functionality for two potential applications – integral microscale imaging devices and light field display technology – thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses.