Extended Data Fig. 9: Directivity measurements.
From: Directive giant upconversion by supercritical bound states in the continuum
a, Microscopy inspection of light propagation near the edge, at which the lateral size of the emitted light remains equal to the input beam waist. Notably, the output collimation is unaffected by the input focusing owing to the influence of the BIC point wavevector. The inset shows the interference pattern resulting from the spatial coherence of the emitted wave. b, Experimental side emission directed along the outer edge versor. c, Polar plot of the edge emission, in agreement with the simulation in Extended Data Fig. 8.