  We show that a cylindrical lensing system composed of two metasurfaces with
suitably tailored non-Hermitian (i.e., with distributed gain and loss) and
nonlocal (i.e., spatially dispersive) properties can perform magnified imaging
with reduced aberrations. More specifically, we analytically derive the
idealized surface-impedance values that are required for "perfect"
magnification and imaging, and elucidate the role and implications of
non-Hermiticity and nonlocality in terms of spatial resolution and practical
implementation. For a basic demonstration, we explore some proof-of-principle
quasi-local and multilayered implementations, and independently validate the
outcomes via full-wave numerical simulations. We also show that the metasurface
frequency-dispersion laws can be chosen so as to ensure unconditional stability
with respect to arbitrary temporal excitations. These results, which extend
previous studies on planar configurations, may open intriguing venues in the
design of metastructures for field imaging and processing.
