Diameter of a focal spot for non-Gaussian beams with a finite energy

It is shown analytical and by a modeling, that radial symmetrical non-gauss paraxial beams with finite energy can help to reduce focal spot diameter in comparing with Gaussian beams in several times. In addition, examined non-gauss beams have an uncertainty relation calculated in half maximum intensity less in 4 times, then for Gaussian beam. Sharp focus modeling for such non-gauss beams with linear polarization shown an ability of reducing focal spot in 2 times in comparing with Gaussian beam.