How can I deform a wavefront?
Any wavefront can be modified by optical elements such as lenses or mirrors. In general a wavefront is modified every time the optical path length (OPL) i.e. the travelled length times the index of refraction is not the same along the wavefront domain. If one uses elements that can introduce differences in OPL the wavefront can be modified. Adaptive Optics elements such as deformable mirrors do exactly this with the plus that one can choose the deformation to give to the wavefront.
