论文标题
实现沿合成轨道角动量维度的特殊点
Realization of exceptional points along a synthetic orbital angular momentum dimension
论文作者
论文摘要
特殊点（EPS），其中一个以上的特征值和特征向量结合是非热质（NH）系统的独特光谱特征。它们广泛存在于具有复杂能量光谱的开放系统中。我们通过实验表明，沿合成轨道角动量（OAM）尺寸具有可调参数，在定期驱动的退化光腔中配对EP的外观。通过检测空腔的传输频谱，可以直接观察复杂的能量带结构和EPS的关键特征，即EPS的Fermi弧，平均时间对称性破坏过渡，能量交换和半整数带绕组。我们的结果提高了对NH物理学的基本理解，并证明了使用光子合成维度实现NH系统的灵活性。
Exceptional points (EPs), at which more than one eigenvalue and eigenvector coalesce, are unique spectral features of Non-Hermiticity (NH) systems. They exist widely in open systems with complex energy spectra. We experimentally demonstrate the appearance of paired EPs in a periodical driven degenerate optical cavity along the synthetic orbital angular momentum (OAM) dimension with a tunable parameter. The complex-energy band structures and the key features of EPs, i.e. their Fermi arcs, parity-time symmetry breaking transition, energy swapping, and half-integer band windings are directly observed by detecting the cavity's transmission spectrum. Our results advance the fundamental understanding of NH physics and demonstrate the flexibility of using the photonic synthetic dimensions to implement NH systems.
