Organic crystal active waveguide as an all-angle signal receiver and transmission platform for encrypted visible light communication

Organic crystal waveguides, known for their excellent versatility in active and passive light-guiding, offer a promising alternative to conventional optical media in visible light communication (VLC) systems. As an example, here we show the use of an organic crystal, 2,2'-((1E,1'E)-hydrazine-1,2-diylidenebis(methaneylylidene))diphenol (SAA) with high photoluminescence quantum yield (≈25%), as an active optical waveguide medium for the real-time and error-free data communication in the visible spectral range. Employing the optical properties of SAA, the versatility of the organic crystal to modulate signals via dual active and passive waveguiding is demonstrated. The crystal's unique capability as an all-angle signal receiver for data transmission is demonstrated utilizing a microcontroller unit with ON-OFF keying modulation, surpassing the performance of conventional optical fibers. A prototypical real-time data transfer device is realized, capable of transmitting streams directly from the serial interface and reconstructing grayscale images with high fidelity. Overall, this work demonstrates implementation of organic crystal waveguide-based innovative VLC platform, offering a compact and efficient solution for next-generation photonic communication technologies.