Description
Current, forthcoming, and planned weak-lensing surveys are advocated as
a powerful tool to investigate dark energy. Is it a cosmological
constant, a fluid-like dynamic component, a signature of the general
relativity's failure, or a signature that general relativity is not yet
fully exploited? Here, I present a geometric description of weak-lensing
which allows for the contribution of tensor perturbations (GWs) in a
non-flat RW geometry, and which turns suitable to deal with every metric
theory of gravity. I focus on the signatures on cosmic shear observables
by scalar-tensor theories and ordinary quintessence scenarios, using
CFHTLS data combined with SNe and CMB data to constrain two simple
models. The analysis is done in perspective of a DUNE-like space-based
wide field imager.