摘要: Photons play essential roles in fundamental physics and practical
technologies. They have become one of the attractive informaiton carriers for
quantum computation and quantum simulation. Recently, various photonic degrees
of freedom supported by optical resonant cavities form photonic synthetic
dimensions, which contribute to all-optical platforms for simulating novel
topological materials. The photonic discrete or continuous degrees of freedom
are mapped to the lattices or momenta of the simulated topological matter, and
the couplings between optical modes are equivalent to the interactions among
quasi-particles. Mature optical modulations enable flexible engineering of the
simulated Hamiltonian. Meanwhile, the resonant detection methods provide direct
approaches to obtaining the corresponding energy band structures, particle
distributions and dynamical evolutions. In this Review, we give an overview of
the synthetic dimensions in optical cavities, including frequency, orbital
angular momentum, time-multiplexed lattice, and independent parameters.
Abundant higher-dimensional topological models have been demonstrated in lower
dimensional synthetic systems. We further discuss the potential development of
photonic synthetic dimensions in the future.