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arXiv · 2212.01009

Metasurface-Based Free-Space Multi-port Beam Splitter with Arbitrary Power Ratio

Tian Tian·Yuxuan Liao·Xue Feng·Kaiyu Cui·Fang Liu·Wei Zhang·Yidong Huang
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Abstract

A beam splitter (BS) is one of the most critical building blocks in optical systems. Despite various attempts of flat-type BSs to miniaturize the conventional cube BS reported, it remains a challenge to realize an ultrathin optical BS with multi-port output, non-uniform splitting ratio and steerable outgoing directions. Herein, we have demonstrated a free-space optical multi-port beam splitter (MPBS) based on a polarization-independent all-dielectric metasurface. By applying an optimized phase-pattern paradigm via a gradient-descent-based iterative algorithm to amorphous silicon (a-Si) metasurfaces, we have prepared a variety of MPBS samples with arbitrarily predetermined output port number (2~7), power ratio and spatial distribution of output beams. The experimental results reveal that the fabricated MPBSs could achieve high total splitting efficiency (TSE, above 74.7%) and beam-splitting fidelity (similarity, above 78.4%) within the bandwidth of 100 nm (1500~1600 nm). We envision that such MPBS could provide fabulous flexibility for optical integrated system and diverse applications.

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Tian Tian, Yuxuan Liao, Xue Feng, Kaiyu Cui, Fang Liu, Wei Zhang, Yidong Huang. 2022-12-02. Metasurface-Based Free-Space Multi-port Beam Splitter with Arbitrary Power Ratio. https://doi.org/10.1002/adom.202300664

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