Zemax Report | Fall 2006 | The University of Tennessee Space Institute

Note:  Both the Tolerance Analysis and the Final Report are in the same document.


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Zemax, Optics, Ray fan, OPD, Apodization, Spot diagram, Root mean square spot size

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Objective: To set up the given optical system (spherically corrected 25 mm F.L. f/2.0 objective) in Zemax using a Gaussian apodization factor of 2 in order to input Gaussian laser beam with waist size equal to (2)-1 times the entrance pupil radius, and wavelength of 632.8 nm, corresponding to a He-Ne laser. Lenses used are 01 LPK 003 and 01 LPX 108 of Melles Griot.

Summary of Tolerancing Analysis

Tolerancing analysis yields possible optical designs for an optical system by taking into consideration the effect of de-centering, tilting, etc., which allows the optical designers to make optical systems efficiently by forecasting the effect of misalignment, etc. on the final image.

The present project involves a spherically corrected 25 mm focal length f/2.0 objective. Tolerancing analysis was performed on this system in sensitivity mode at test wavelength of 632.8 nm, which corresponds to He-Ne laser. The criteria set for this analysis was RMS spot size.

The analysis suggests the possible changes in alignment of the lenses (tolerances corresponding to de-center X and de-center Y, TIRX, TIRY, TSDX, TSDY, Irregularities of surfaces in fringes, Index tolerance and Abbe tolerance). It also includes the possible combinations of misalignments that will result in worst result. The tolerancing analysis shows that the optical components of the system are sensitive to tilt and de-center types of misalignment. It shows the estimated performance changes based on Root-Sum-Square method as:

Nominal RMS spot radius
: 0.039544

Estimated change
: 0.022977

Estimated RMS spot radius
: 0.062522

The analysis also outlines the changes that can be made to back focus as:

: -0.398327

: 0.409846

: 0.000144

Standard Deviation
: 0.103466