A new method for diffraction measurement

There is a reducing-enlarging relation between the dimension and the diffracting intensity for an aperture.This relation may be used for the engineering measurement of tiny dimension.In this paper the reducing-enlarging theorem is developed.The measuring formulas used for slits and apertures,and the expresions of the correcting factor for the photoelectric receiving with an area are given.In the paper the results of measuring experiment to take filaments for example are also given.