Ultra-Wide Modulation and Reversible Reconfiguration of a Flexible Organic Crystalline Optical Waveguide Between 645 and 731 nm

Flexible organic crystalline optical waveguides, i.e., delivering input or self-emit lights through various dynamic organic crystals, have attracted increasing attentions in the past decade. However, the modulation of waveguide outputs relies on chemical design and substituent modification, being time-consuming and laborious. Here we report an elastic organic crystal that displays long-distance light transducing capability up to 2.0 cm and ultra-wide modulation of crystalline optical waveguides between red (645 nm) and near infrared (731 nm) in both the pristine and the elastically bent states based on a pre-designed self-absorption effect. The flexible organic crystalline optical waveguides can be precisely and reversibly reconfigured by controlling irradiation point. In addition, deep red amplified spontaneous emissions (ASE) that are able to transduce through a 5.0 mm bent crystal with an ultra-low optical loss coefficient of 0.092 dB/mm has been attained. To the best of our knowledge, this is the first report of flexible organic ASE waveguides. The present study not only provides a simple yet effective strategy to remarkably modulate flexible organic crystalline optical waveguides but also demonstrates the superiority of laser over normal emission as flexible optical communication elements.