Simultaneous Achievement of Enhanced Nonlinear Optical Absorption and Nonlinear Refraction in Highly Crystalline 2D Covalent Organic Frameworks Ultrathin Films

• DOI: 10.1002/advs.202416170
• Publication Date: 2025-02-11T12:11:01Z
• Authors: Tianyang Dong; Xingyuan Wen; Junyi Li; Xingzhi Wu; Chong Wang; Wenfa Zhou; Lingmin Yu; Yinglin Song; Chunru Wang; Li Jiang; Chunli Bai
• Keywords: Z-scan technique

Large enhancement of nonlinear absorption and refraction are achieved simultaneously in highly ordered two dimensional (2D) covalent organic framework (COF) films prepared by solidliquid interface one-step method to overcome the weakness COF powders solubility. In intrinsic optical response obtained at 532 nm with 5 ns pulse, coefficients (β) -4.87 × 10-5 -1.29 m W-1, respectively. Simultaneously, fitted closed-aperture curves also show large refractive indexes (n2), -5.62 10-12 m2 W-1 -0.76 W-1. The 4f coherent imaging performed same condition a single-shot pulse further verifies outstanding without any damage probably experienced Z-scan technique. Moreover, differences electronic structure photoexcited states between compared explain difference response. All results indicate that crystalline giant can be capable modulating both amplitude phase light, providing huge potential all-optical manipulating switching nanoscale as materials.