Realizing a flexible and wavelength-tunable random laser inspired by cicada wings

A bio-tissue-inspired random laser (RL) has been successfully demonstrated using a dye-covered silk fibroin replica film (DC-SFRF) fabricated through soft lithography of a cicada's wing. Thanks to the increased light scattering between the nanopapillate structures of the DC-SFRF, the RL exhibits a lower lasing threshold, higher slope efficiency, and broader angular emission compared to those of the dye-covered silk fibroin film (DC-SFF). The low spatial coherence NIR RL can also serve as a suitable light source in bio-diagnosis to generate a low speckle noise image with a contrast of approximately 0.040. By employing flexible PET as a substrate, we have demonstrated the flexibility of the near-infrared random laser (NIR RL) through the application of mechanical stress to alter the distribution of nanopapillate structures on the surface of the replica film. As the curvature increases, the DC-SFRF RL exhibits a blue shift of 13.3 nm in the emission spectrum and a further reduction in the speckle contrast to 0.031.