  Optical computing has emerged as a promising candidate for real-time and
parallel continuous data processing. Motivated by recent progresses in
metamaterial-based analog computing [Science 343, 160 (2014)], we theoretically
investigate realization of two-dimensional complex mathematical operations
using rotated configurations, recently reported in [Opt. Lett. 39, 1278
(2014)]. Breaking the reflection symmetry, such configurations could realize
both even and odd Green's functions associated with spatial operators. Based on
such appealing theory and by using Brewster effect, we demonstrate realization
of a first-order differentiator. Such efficient wave-based computation method
not only circumvents the major potential drawbacks of metamaterials, but also
offers the most compact possible device compared to the conventional bulky
lens-based optical signal and data processors.
