When tolerancing for various manufacturing/assembly defects of an optical system, it is sometimes important to consider effects of inhomogeneity, or irregular variations of refractive index in the glass.

Although ZEMAX does not have a specific tolerance operand for inhomogeneity, a statistical method via the TEZI operand can be used instead, which tolerances for irregular deviations of small amplitude on a surface.

The Monte Carlo tolerance analysis is used to randomize the inhomogeneity (irregularity) and provide you with accurate, statistical results of how this irregularity is affecting the performance of your optical system.

References

1.  Schott AG (July 2004).  TIE – 26: Homogeneity of optical glass.  In Technical Information – Optics For Devices (Section 2.2).  Retrieved from http://www.us.schott.com/optics_devices/english/download/tie-26_homogeneity_of_optical_glass_us.pdf

2.  ZEMAX Optical Design Program User’s Guide, ZEMAX Development Corporation