A Transparent, High Refractive Index and Abbe Number Polymer for Visible Metalens by High Fidelity Nanoimprinting.

Guo, Jianrong; Chen, Hongbin; Wang, Ziyu; Cheng, Yuan-Yuan; Fu, Ji Chao; Liu, Siqi; Hu, Jun; Huang, Binting et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

Simultaneously achieving high visible transparency, high refractive index (n), and a large Abbe number (υ<sub>D</sub>) in organic polymers remains a fundamental challenge. Here, a facile and efficient dual sulfur-mediated Michael addition strategy is reported to synthesize transparent high refractive index polymers (HRIPs) with large υ<sub>D</sub>. By combining main backbone de-conjugation to preserve visible transparency with rational side-chain engineering for n-tuning, the optimal polymer (H4) achieves an ultrahigh n of 1.86 at 589 nm alongside a large υ<sub>D</sub> of 34.93 and robust stability. Moreover, polymer H4 exhibits remarkable performance in nanoimprint lithography, replicating features down to 75 nm with aspect ratios up to 8.5 and a low volumetric shrinkage of only 3.23%. Notably, a nanoimprinted metalens prototype fabricated from H4 delivers a relative focusing efficiency of 49.8% at 550 nm (NA = 0.5), approaching the theoretical design value (52.94%). Therefore, the high refractive index polymer H4 bridges molecular design and manufacturable meta-optics, showing tremendous potential in scalable, flexible, next-generation photonic platforms by translating side-chain polarizability engineering into practical wavefront control.