Replica symmetry breaking in enteromorpha prolifera-based random laser

Random lasers (RLs) differ fundamentally from conventional lasers by replacing engineered optical cavities with disorder-mediated multiple scattering feedback, enabling cavity-free emission through photon interactions in disordered gain media. RLs have demonstrated many application potentials in the domains of optics and optoelectronics because of their low coherence, multidirectionality, and multiple wavelengths. However, the principle and procedure of RL generation, as well as the method for achieving low-threshold emission, still present difficulties. This study demonstrates the replica symmetry breaking (RSB) in coherent RL systems utilizing Enteromorpha prolifera (EP), a marine bio-scatterer exhibiting multiscale photonic architecture. The transition from the photon paramagnetic phase to the spin glass phase is seen with the increase of the pump energy in this random liquid phase system. The multiscale structure of EP enables efficient dye adsorption while enhancing photon scattering to amplify optical feedback, thereby achieving stable coherent random lasing with a low threshold. Power Fourier transform analysis was employed to calculate the effective optical cavity length of the RL system, depicting the coherent lasing dynamics and determining the free spectral range. The bio-enabled RL system demonstrated remarkable spatial coherence control with good speckle-free imaging potentials through quantitative analysis of speckle contrast and derived mode numbers, revealing pump-energy-dependent correlations that elucidate intermodal interaction dynamics. These findings advance the fundamental understanding of disordered photonic systems while establishing a sustainable framework for engineering bio-derived RL sources with tailored coherence properties.