Fig. 5: Experimental demonstration of an efficient beam deflector with reduced adjacent coupling.

a SEM images of the fabricated GM and an enlarged view of one unit cell. Each SU with a different orientation shows different values of d_1,2,3,4. The red dashed lines mark the edges of the air gaps. b, c Measured (b) and simulated (c) transmittances of cross-CP and co-CP light as functions of the wavelength and output angle for a RCP input with normal incidence. The dashed lines represent the theoretical diffraction angle of the anomalous diffractions. d Measured and simulated deflection efficiencies of anomalous diffraction in transmission and the related ER over normal diffraction. The solid, dashed, and dash-dotted lines represent the experimental results, simulation of noncomplementary GM, and simulation of complementary GM, respectively. In the simulation of the noncomplementary GM, the d_1,2,3,4 values of each SU are set as the averaged values measured in (a). Detailed values are provided in SI Fig. S12b. The measured efficiency is higher than that from the simulation of the complementary GM by ~17.5%, which is larger than the improvement of the regular MPM described in Fig. 4 and confirms the benefit of the noncomplementary design in reducing adjacent coupling. e Far-field diffraction patterns of the beam deflector at 750 nm for LP, RCP, and LCP inputs