Initiation-Confined Holographic Photopolymerization under Visible Light

Holographic photopolymerization provides a robust approach for the advanced manufacturing of structurally ordered devices. However, photogenerated radicals in bright regions are prone to cross-regional diffusion and induce unwanted polymerizations in dark regions, making efficient holographic manufacturing exceedingly challenging. Herein, we report a breakthrough by spatially confining the initiation function, enabling the unprecedentedly rapid formation of predesigned submicron-ordered grating structures within merely 0.75 s under visible light holographic exposure. Theoretical computations attribute the success of this initiation-confined approach to orders of magnitude larger reaction rate constants of initiation than propagation. This approach is highly versatile, facilitating the fabrication of both transmission- and reflection-type volume holographic grating structures starting from various reaction systems, and the refractive index modulation can be as high as 0.10, enabling ultraefficient manufacturing of waveguide combiners for high-fidelity near-eye AR displays.