  One of the main advantages of reciprocal bianisotropic metasurfaces is their
capability to produce asymmetric scattering depending from which side they are
illuminated and on the handedness of circularly polarized illuminations. For
most applications, these metasurfaces are designed for illumination by a single
source at a time. The resulting bianisotropic metasurface has a specific and
usually complex geometrical structure that ensures the expected scattering
produced under various illuminations. Here we show that geometrical asymmetry
of metasurfaces can be emulated by using non-bianisotropic layers in presence
of coherent illumination, which allows us to replicate and optically control
the desired asymmetric scattering and chirality effects. In particular, the
concept is developed on an example of emulating asymmetric scattering needed to
create a 180$^\circ$ hybrid junction for plane waves. We show that this device
can be realized either using a bianisotropic metasurface or a set of simple
sheets with electric response under simultaneous illumination by two coherent
waves.
