Extended Data Fig. 1: Increasing the dimensionality of a two-dimensional lattice of waveguides.
From: Photonic topological insulator in synthetic dimensions
a, One-dimensional columns arranged in a two-dimensional lattice. The columns oscillate along the black paths in the direction indicated by the triangles. Red and blue colours indicate different columns in the same unit cell. b, Representation of a in synthetic dimensions. c, Lattice with two oscillation frequencies, oscillating in the x direction according to Δx and with index of refraction changing periodically according to Δn. d, Representation of c in synthetic dimensions.
