a, The spectra and schematics of the high-efficiency optical non-Hermitian meta-system at EP. The |r-1| is larger than 0.999 and |r+1| is less than 10-4. b, Trajectories of eigenvalues with the evolution of absorption parameter. c, The amplitude of non-specular reflection coefficients r-1 and r+1 by varying absorption parameter.

a, Top view and back view of the sample. The upper layer is TiO2 metagrating and the lower layer is Si grating. b, The far-field scattered light from all angles of the sample with incident angles of 30° and -30°. c, The experimental measured far-field scattered light from all angles with incident angles of 30° and -30° at 532 nm.