Hello, I need to calculate diffraction picture produced by source generating partially coherent illumination. I read Born and Wolf, Goodman and still I do not have complete understanding. Suppose we have source with size d, simple object (let's take opaque rectangle) and detector. According to illumination wavelength, object size and setup geometry image can be calculated in Fresnel approximation. How shall I calculate image considering that source produces partially coherent radiation with degree of coherency [tex]\gamma[/tex]? From what I have found: I can take wave field P(x,y)=P0(x,y)exp[ikW(x,y)] - amplitude and phase of wave right after it passes through the object). I know Raleigh Sommerfeld RS propagator h(x,y). Than I can calculate image for point radiator: I(x,y)=abs(F-1F(P)F(h))2 (F is fast fourier transform) And take convolution of this value over all point radiatiors in the source. Is it case of coherent or incoherent illumination? What about convolution of intensities Iincoherent=|h|2convolved with|P|2 ( formula from Goodman, Fourier Optics sec 6.5.1) Shall I take squared modulus of wave field and RS (plain wave etc.) propagator and than calculate like this: Iincoh(x,y)=F-1F(abs(h)2)F(abs(P)2) ??? How I have to take into account convolution over source size in this case? And what about this formula? Ipartially coherent=[tex]\gamma[/tex]Icoh+(1-[tex]\gamma[/tex])Icoh ??? Can I use it? I also found in Born Wolf that main value for the partially coherent illumination is Mutual Intensity, how can I calculate it and is it necessary? Could you please clarify this for me?