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
z distance from the the mirror vertex to the waist of the incident beam
lam : wavelength
R : mirror radius
M2x : M square factor (M2) in the XZ plane
M2y : M square factor (M2) in the YZ plane
wix : half width of the reflected beam waist in the XZ plan
wiy : half width of the reflected beam waist in the YZ plane
zix : distance from the mirror vertex to the waist of the reflected beam in the XZ plane
ziy : distance from the mirror vertex to the waist of the reflected beam in the YZ plane
