Non-invasive imaging using a low-spatial-coherence multimode random polymer fiber laser

Random lasers (RLs), with their low spatial coherence, are ideal illumination sources for speckle-free imaging. However, it is still challenging for RLs to maintain low spatial coherence with the need for integration and directionality. Here, a disordered multimode random polymer fiber laser (RPFL) is proposed and implemented as a low-spatial-coherence light source. Compared to typical multimode optical fibers, the number of accommodated modes is increased by about 11×, the speckle contrast is reduced to 0.013, and the spatial coherence factor is reduced to 0.08. The low-spatial-coherence property enables RPFL to produce significantly superior imaging quality in both speckle-free imaging and non-invasive imaging through opacity. This study provides a strategy for an integrated speckle-free imaging system and paves the way for non-invasive imaging.