Reconstruction of scattered light field via broadband modulation instability

Precise reconstruction of scattered fields remains a challenge. Here, we report a nonlinear approach via broadband modulation instability in co-doped polymers. Theoretical analysis and experimental observation show that the complementary action of photo-isomerization and photorefractive effects on instability leads to a broader gain bandwidth of 0.71 μm^-1 for regenerating and amplifying high-frequency modes, approximately three times broader than that of photorefractive crystals. As a result, scattered images are restored with high resolution. This work paves a way for precise wavefront engineering and related applications, such as dynamic holography, target imaging, and optical communication.