  Recently, we have suggested dielectric metamaterial composed as an array of
submicron dielectric spheres located on top of an amorphous thin-film solar
cell. We have theoretically shown that this metamaterial can decrease the
reflection and simultaneously can suppress the transmission through the
photovoltaic layer because it transforms the incident plane wave into a set of
focused light beams. This theoretical concept has been strongly developed and
experimentally confirmed in the present paper. Here we consider the
metamaterial for oblique angle illumination, redesign the solar cell and
present a detailed experimental study of the whole structure. In contrast to
our precedent theoretical study we show that our omnidirectional light-trapping
structure may operate better than the optimized flat coating obtained by
plasma-enhanced chemical vapor deposition.
