Subjects: Optics >> Quantum optics submitted time 2023-02-19
Mu Yang
Hao-Qing Zhang
Yu-Wei Liao
Zheng-Hao Liu
Zheng-Wei Zhou
Xing-Xiang Zhou
Jin-Shi Xu
Yong-Jian Han
Chuan-Feng Li
Guang-Can Guo
Abstract： 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.
Peer Review Status:
Awaiting Review
Subjects: Optics >> Quantum optics submitted time 2023-02-19
Mu Yang
Hao-Qing Zhang
Yu-Wei Liao
Zheng-Hao Liu
Zheng-Wei Zhou
Xing-Xiang Zhou
Jin-Shi Xu
Yong-Jian Han
Chuan-Feng Li
Guang-Can Guo
Abstract： Synthetic dimensions based on particles' internal degrees of freedom, such as frequency, spatial modes and arrival time, have attracted significant attention. They offer ideal large-scale lattices to simulate nontrivial topological phenomena. Exploring more synthetic dimensions is one of the paths toward higher dimensional physics. In this work, we design and experimentally control the coupling among synthetic dimensions consisting of the intrinsic photonic orbital angular momentum and spin angular momentum degrees of freedom in a degenerate optical resonant cavity, which generates a periodically driven spin-orbital coupling system. We directly characterize the system's properties, including the density of states, energy band structures and topological windings, through the transmission intensity measurements. Our work demonstrates a novel mechanism for exploring the spatial modes of twisted photons as the synthetic dimension, which paves the way to design rich topological physics in a highly compact platform.
Peer Review Status:Awaiting Review
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