Fig. 5. Experimental results of Young’s double-slit interference.

a Schematic view of the experimental setup. L, Lens. The double-slit distance is d. The double slit is mounted on the real image plane. The red arrow lines show the radiation fields from two different positions on the sample. b The experimental results for the case of a 6-micron effective double-slit distance. The real double-slit distance d is 120 microns. The magnification of the real image is 20, so the effective double-slit distance on the sample is 6 microns. The upper panel shows the WS₂ monolayer on the PhC slab without in-plane inversion symmetry. The lower panel is for the WS₂ monolayer on a flat substrate, with the signal intensity shown at two-fold magnification. The detection plane is along the Γ-X direction. c The interference intensity distribution in b at 621 nm. The far-field emission of the WS₂ monolayer on the PhC slab without in-plane inversion symmetry has a long-distance spatial coherence property