  Despite all the success with developing super-resolution imaging techniques,
the Abbe limit poses a severe fundamental restriction on the resolution of
far-field imaging systems based on diffraction of light. Imaging with contact
microlenses, such as microspheres or microfibers, can increase the resolution
by a factor of two beyond the Abbe limit. The theoretical mechanisms of these
methods are debated in the literature. In this work, we focus on the recently
expressed idea that optical coupling between closely spaced nanoscale objects
can lead to the formation of the modes that drastically impact the imaging
properties. These coupling effects emerge in nanoplasmonic or nanocavity
clusters, photonic molecules, or various arrays under resonant excitation
conditions. The coherent nature of imaging processes is key to understanding
their physical mechanisms. We used a cluster of point dipoles, as a simple
model system, to study and compare the consequences of coherent and incoherent
imaging. Using finite difference time domain modeling, we show that the
coherent images are full of artefacts. The out-of-phase oscillations produce
zero-intensity points that can be observed with practically unlimited
resolution (determined by the noise). We showed that depending on the phase
distribution, the nanoplasmonic cluster can appear with the arbitrary shape,
and such images were obtained experimentally.
