Engineering high directional sensitivity in non-diffracting metasurfaces

Compact Optical components sensitive to incident wave-vector direction are essential in image-processing, wavefront-manipulation, and metrology such as LIDAR. Here we demonstrate a new class of metasurfaces which exhibit optical spectral features strongly correlated with incident illumination angle. The spectra of such metasurfaces feature sharp transmission dips centred around 800 nm when illuminated at oblique incidence, where the strength of the dip increases as incident angle increases remaining tightly confined within a 100 nm band. The metasurfaces are capable of accepting large incident angles (>30°) without the appearance of higher-order diffraction modes, while displaying dramatic transmission decreases (~80% reduction).