  Advances in optical imaging always look for an increase in sensitivity and
resolution among other practicability aspects. Within the same scope, in this
work we report a versatile interference contrast imaging technique, capable of
sub-nm sample-thickness resolution, with a large field-ofview of several mm2.
Sensitivity is increased through the use of a self-imaging non-resonant cavity,
which causes photons to probe the sample in multiple rounds before being
detected, where the configuration can be transmissive or reflective. Phase
profiles can be resolved individually for each round thanks to a specially
designed single-photon camera with time-of-flight capabilities and true
pixels-off gating. Measurement noise is reduced by novel data processing
combining the retrieved sample profiles from multiple rounds. Our protocol is
specially useful under extremely low light conditions as require by biological
or photo-sensitive samples. Results demonstrate more than a four-fold reduction
in phase measurement noise, compared to single round imaging, and close
valuesto the predicted sensitivity in case of the best possible cavity
configuration, where all photons are maintained until n rounds. We also find a
good agreement with the theoretical predictions for low number of rounds, where
experimental imperfections would place a minor role. The absence of a laser or
cavity lock-in mechanism makes the technique an easy to use inspection tool.
