Diffractive imaging route to sub-wavelength pixels

We propose optical imaging technique that relies on diffractive rather than refractive elements. Our approach takes advantage of metagratings, structures with engineered diffraction properties, and natural materials with sufficiently high refractive indices to achieve significant reduction in pixel size. In contrast to conventional refraction-based imaging, the developed approach essentially produces a digital hologram, a low-dimensional projection of the volumetric optical field. The perspectives of numerical recovery of the optical field and the stability of such recovery are discussed. (C) 2013 AIP Publishing LLC.