Extended Data Fig. 3: Polariton propagation.
From: Polariton Bose–Einstein condensate from a bound state in the continuum
a, Excitation scheme for propagation measurements; the red spot outside the grating represents the non-resonant exciting laser beam. b, Polariton dispersion obtained by pumping the sample with the scheme in a; only polaritons propagating upwards reach the grating. c, Polariton group velocity extracted from the fitted dispersion in b.
