CMB lensing signal analysis: prospects for measurements and characterisation for future surveys

Within the last few years, Cosmic Microwave Background gravitational lensing has become a new tool for cosmology and astrophysics. As a new independent kind of measurement in this field, it can help to break the degeneracy between the cosmological parameters and determining their values with a better accuracy. This field of research is becoming increasingly prominent and fertile in the latest years, both as a way to investigate the evolution of the Universe at late times, and in relation to the EUCLID mission preparatory science work, aiming at mapping galaxies on ABOUT 30% of the sky reaching a redshift of about 2. The aim of this thesis is to characterise the lensing signal in the CMB and to study the efficiency of lensing extraction at small angular scales from simulated CMB maps lensed by N-body simulations, and how this translates in constraining Dark Energy and its relevant parameters for the expansion. After investigating the balance between the tensor modes and lensing in the B−mode power spectrum, the feasibility of lensing extraction on CMB lensed N-body simulations is demonstrated: the faithfulness of the implemented pipeline is assessed and verified for upcoming experimental setups and validated ranging from the degree to the arcminute scale.