Parameters
wx : half width of the incident beam waist in the XZ plane
wy : half width of the incident beam waist in the YZ plane
zx distance from the lens to the incident beam waist in the XZ plane
zy distance from the lens to the incident beam waist in the YZ plane
lam : wavelength
fi : effective focal length of the lens
M2x : M square factor (M2) in the XZ plane
M2y : M square factor (M2) in the YZ plane
wix : half width of the emerging beam waist in the XZ plane
wiy : half width of the emerging beam waist in the YZ plane
zix : distance from the lens to the emerging beam waist in the XZ plane
ziy : distance from the lens to the emerging beam waist in the YZ plane
