Metasurface metal-organic framework film for highly nonlinear optical amplification

The integration of metasurface with resonant structural features on metal-organic frameworks (MOF) materials provides a promising strategy for the breakthroughs in achieving nonlinear optical (NLO) amplification but has not yet been reported. Herein, metasurface MOF (Cu-PcCu) films composed of phthalocyanine ligand were successfully fabricated by combining metasurface nanoarrays template and liquid phase epitaxial layer-by-layer strategies. Compared to flat MOF films, the metasurface MOF film exhibits greatly enhanced broadband superabsorption and amplified third-order NLO effects across the visible to near-infrared spectral regions. Notably, the third-order nonlinear absorption coefficients (β) of the metasurface MOF film were approximately 10 times higher than those of flat films at the wavelengths of 532 nm. Finite difference time domain (FDTD) simulation proves that the enhanced optical properties of metasurface MOF film are mainly due to the resonance effects of electric dipoles. The presented work proposes a novel strategy for achieving third-order NLO amplification by integrating metasurface nanoarrays and MOF film, offering a new pathway for developing high-performance NLO materials for practical applications.