The physics of a photonic structure is commonly described in terms of its apparent geometric dimensionality. We review the basic concepts of synthetic dimension in photonics, and highlight the various approaches toward demonstrating such synthetic dimensions for fundamental physics and potential applications. In particular, we introduce the synthetic space involving the frequency axis of light in a photonic system undergoing the refractive index modulation. We show that, in such a synthetic space, the phase of the modulation corresponds to the effective photonic gauge potential. As a result, higher-dimensional physics, especially topological physics, can be explored in low-dimensional physical structures, leading to new possibilities for manipulating the frequencies of light in non-trivial ways.
2018-11-30 (周五) 10:00