Amphibian‐like Flexible Organic Crystal Optical Fibers for Underwater/Air Micro‐Precision Lighting and Sensing

Abstract Visible light guiding optical fibers with underwater operational capability are highly desired for subaquatic communication and sensing technologies. Herein, we present mechanically flexible, blue‐violet fluorescent (4,4′‐bis(2,6‐di(1 H ‐pyrazol‐1‐yl)pyridin‐4‐yl)biphenyl) (BPP) crystal waveguides with high‐aspect ratio. These milli‐meter‐long BPP crystals guide light actively and passively in ambient and underwater conditions demonstrating their amphibian‐like character. Due to the crystal's high flexibility, the optical fiber's output light direction in submerged and ambient states can be altered mechanically for high‐precision lighting and sensing applications. The development of such multi‐environment‐compatible and mechanically flexible organic optical fibers acting as sensing materials possess enormous potential for short‐range underwater photonic technologies.