  Random media introduce large degrees of freedom in device design and can thus
address challenges in manipulating optical waves. Wave shaping with
metasurfaces has mainly utilized periodic or quasi-periodic grids, and, the
potential of random arrangement of particles for devices has only come under
investigation recently. The main difficulty in pursuing random metasurfaces is
the identification of the degrees of freedom that optimize their efficiencies
and functions. They can also encode information using the statistics of
particles distribution. We propose a phase-map that accounts for the
statistical nature of random media. The method takes into account effects of
random near-field couplings that introduce phase errors by affecting the phase
shift of elements. The proposed approach increases the efficiency of our random
metasurface devices by up to ~20%. This work paves the way towards the
efficient design of random metasurfaces with potential applications in highly
secure optical cryptography and information encoding.
