The atmosphere has a turbulent which produces aberrations on the wavefront of what otherwise would be a point source of laser light in the case of free-space optical communications, as well as it is the case for starlight when a telescope is pointed at a distant star. This problem is of special relevance in the arise of extremely large telescopes, as a bigger aperture encompasses the collection of more patches of an already turbulent atmosphere. Therefore, innovative adaptive optic techniques must be applied in order to exploit the outstanding resolution that can be achieved only at the diffraction limit of telescopes such as GTC, TMT, or ELT.

In this talk we present results incoming from applying Spatial Light Modulators (SLM) as the core element both for sensing and correcting the wavefront distortions. Instead of the common approach, which involves the use of Deformable Mirrors (DM), we make use of liquid-crystal-on-silicon (LCOS) SLM's, which can digitally modify the refractive index of each of the nearly half a million pixels it possess. In the sensing aspect we implement the novel Diffractive Wavefront Sensor (DWS) that can produce a wavefront directly from the image obtained after placing a diffractive element in the focal plane. Experimental results indicate robustness against obscurations and diffraction (caused by segmented mirrors and structures ubiquitous in large telescopes), and a spatial resolution orders of magnitude higher that the well known Shack-Hartman sensor.