  Non-Hermitian systems exploiting the synergy between gain and loss have
recently become the focus of interest to discover novel physical phenomena. The
spatial symmetry breaking in such systems allows tailoring the wave propagation
at will. Inspired by such property, we propose a feasible approach based on
local Hilbert transform to control the field flows in two- or higher
dimensional non-Hermitian systems, restricting the complex refractive index
within practical limits. We propose an iterative procedure to reduce the
dimensionality of complex refractive index parameter space to two, one or zero
dimensions. The proposed method provides a flexible way to systematically
design locally PT-symmetric systems realizable with a limited collection of
realistic materials.
