The invention discloses a rapid calculation method for realizing tight focusing of partially coherent light. The method comprises the following steps: S10, enabling one part of coherent
light beam tobe expanded into a plurality of completely coherent sub light sources and enabling the plurality of completely coherent sub light sources to be independent from each other; S20, enabling the pluralityof completely coherent sub light sources to respectively pass through a tight focusing
system and acquiring tight focusing
light field distribution respectively corresponding to the plurality of completely coherent sub light sources by utilizing a tight focusing
fast algorithm; S30, carrying out incoherent superposition on the obtained distribution of the plurality of tightly focused light fieldsto obtain a superposed total
light field so as to obtain tightly focused focal field distribution under the partially coherent
light beam incident condition. According to the disclosed method, the quadruple integral form of a vector
diffraction integral formula under the condition of partial coherent light incidence is changed into a
fast Fourier transform and summation form, so that the calculation time is shortened, the calculation efficiency is improved, and the tight focusing calculation precision under the condition of
partial coherence is greatly improved; and the
distortion in the calculation process is also reduced.