Two‐Photon Laser Writing of Sub‐Diffraction Three‐Dimensional Luminescent Perovskite Architecture Embedded in Non‐Luminescent Perovskite

As emerging high‐performance optoelectronic materials, metal halide perovskites display outstanding advantages in micro‐nano optoelectronic integration. However, high‐precision multidimensional processing and on‐demand dynamic modulation of the luminescent properties of perovskites remain urgent challenges. In this work, we present a femtosecond laser two‐photon‐induced in situ phase transition strategy that enables the precise construction of highly luminescent multidimensional perovskite heterostructures within non‐emissive perovskite single crystals. We systematically investigate the regulatory effects of key laser parameters, including energy density and pulse repetition rate, on the phase transition process, and successfully fabricate patterns with sub‐diffraction‐limit resolution. Moreover, by incorporating artificial intelligence algorithms, we accomplish point‐by‐point writing of multilayer anti‐counterfeiting information at various depth planes, converting conventional 2D planar tags into 3D stereoscopic anti‐counterfeiting architectures. This two‐photon laser processing strategy based on in situ phase transition provides a new route for the high‐precision 3D integration of perovskite‐based optoelectronic devices.