I want to design a Gaussian beam (laser, coherent source) with a divergence angle of 0.3 mrad, i.e. 0.3 mm (FWHM) at the 1 meter point.
w0(1/e^2) = 0.8493218 x FWHM
When using the above formula, the beam size (1/e^2) at the 1M point was calculated to be approximately 0.510mm.
Using this value and the wavelength of 13.5nm, the Gaussian source's beam size and position were calculated and entered.
However, when I place the detector at the 1M point, change the Detector viewer's Data from incoherent irradiance to coherent irradiance, and use the FWHM macro, it appears to have 0.22mm.
I used the FWHM macro below.
ZPL Operand: Extract FWHM from non-sequential detector | Zemax Community
which part of my method is wrong?
If possible, can you share the files you designed?