Experiments demonstrating the existance of Poisson's Spot (the diffractive "focus" point of an aragoscope) have been made and well understood for 200 years.
While the point is brighter than the surrounding shadow, the maximum power intensity on axis is no greater than the undisturbed wavefront (what would be present without the obscuration).
Even if everything else was correct (point source or collimated light, correct distances and sizes for whatever geometry you choose), the intensity at any point on the Earth would not be any greater than usual.