Highly Flexible, Stretchable, and Tunable Optical Diffusers with Mechanically Switchable Wettability Surfaces

Highly stretchable and super-hydrophobic photonics provides a new geometric degree of freedom for photonic system design and self-cleaning applications. Here, we describe the design and experimental realization of mechanically stretchable and tunable photonic diffusers. These intrinsically designed diffusers (based on periodic arrays of cylindrical lenslets and microtip) were made directly on elastomer material using laser ablation. The dimensions of both the tips and the lenslet arrays play a critical role in the distribution of illumination and wettability resistance. By stretching the diffusers mechanically along the lenslet arrays, diffusion angle tuning was achieved and also a reversible change between hydrophilic to super-hydrophobic states. These multifunctional diffusers constitute an important step toward integration with flexible materials or devices such as stretchable organic light-emitting diodes and polymer light-emitting diodes.