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arXiv:2403.08233

A Parallel Beam Splitting Based on Gradient Metasurface: Preparation and Fusion of Quantum Entanglement

Qi Liu, Xuan Liu, Yü Tian, Zhaohua Tian, Guixin Li, Xi‐Feng Ren, Qihuang Gong, Ying Gu

Published Mar 13, 2024• 0 citations
arXivHTMLPDF

Abstract

Gradient metasurface, formed by a set of subwavelength unit cells with different phase modulation, is widely used in polarized beam splitting (BS) in the classical and quantum optics. Specifically, its phase gradient allows the path and polarization of multiple output lights to be locked by corresponding inputs.Using this unique path-polarization locked property, we demonstrate that the single metasurface can function as sequentially linked beamsplitters, enabling the parallelization of a series of BS processes. Such a parallel BS metasurface provides a multi-beam interference capability for both classical and quantum light manipulation. Taking this advantage, we first prepare path and polarization hybrid entangled states of two, three, and multi photons from unentangled photon sources. Then, the ability of parallel BS-facilitated entanglement is applied to demonstrate entanglement fusion among entangled photon pairs, which can greatly enlarge the entanglement dimension. The principle of parallel BS through the metasurface opens up a versatile way to manipulate the quantum state at the micro/nano scale, which will have potential applications in on-chip quantum optics and quantum information processing.

DOI
10.48550/arxiv.2403.08233

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Multiphoton entanglement with high information capacity plays an essential role in quantum information processing. The appearance of parallel beam splitting (BS) in a gradient metasurface provides the chance to prepare the multiphoton entanglement in one step. Here, we use a single metasurface to construct multiphoton path-polarization entanglement. Based on the parallel BS property, entanglement among N unentangled photons is created after they pass through a gradient metasurface. Also, with this ability, entanglement fusion among several pairs of entangled photons is set up, which can greatly enlarge the entanglement dimension. These theoretical results pave the way for manipulating metasurface-based multiphoton entanglement, which holds great promise for ultracompact on-chip quantum information processing.
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