  Abbe diffraction limit fundamentally bounds the resolution of conventional
optical imaging and spectroscopic systems. Along the years, several schemes
have been introduced to overcome this limit, each offering opportunities and
trade-offs. Metamaterials have been proposed as a promising platform in this
context, in principle enabling superlenses capable of drastic resolution
enhancements. However, their performance is severely hindered by material loss
and nonlocal phenomena, which become increasingly more detrimental as we
attempt to image more subwavelength details. Active metamaterials have been
explored to overcome these challenges, however material gain introduces other
obstacles, e.g., instabilities, nonlinearities and noise. Here, we demonstrate
that the temporal excitation of passive superlenses using signals oscillating
at complex frequencies compensates material loss, leading to resolution
enhancement. Our results demonstrate that virtual gain stemming from tailored
forms of excitation can tackle the impact of loss in superlenses. More broadly,
our work opens promising avenues for loss compensation in metamaterials, with a
broad range of applications extendable to optics and nanophotonic systems.
