Computing Monochromatic Aberrations
The Optical Aberration plot and the Aberration Evaluation derived values node are used to analyze the performance of lens systems within the limit of the geometrical optics approach. In order to use the Optical Aberration plot, the following prerequisites must be met:
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The model component must be 3D.
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An instance of the Geometrical Optics interface must be present and solved for.
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The Compute optical path length check box must be selected in the Geometrical Optics Settings window before solving.
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An Intersection Point 3D data set must be created. This data set must point to a Ray data set.
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In the Settings window for the Intersection Point 3D data set, Hemisphere must be selected from the Surface type list. The Center is the location of the focus and the Axis direction points from the focus toward the center of the exit pupil.
Using the hemisphere defined in the Intersection Point 3D data set, a Gaussian reference sphere is defined. The Optical Aberration plot or Aberration Evaluation feature then computes the optical path length at the intersection points of rays with this Gaussian reference sphere and computes the Zernike coefficients that best fit the optical path difference distribution.
Figure 2-7: Ray trajectories through a simple plano-convex lens (top) and the resulting monochromatic aberrations (bottom). Zernike polynomials: sum of all terms (far left), defocus (left), spherical aberration (right), and all other terms (far right).
 
For a list of Zernike polynomials and their derivation, see Monochromatic Aberrations and Zernike Polynomials in Theory for the Geometrical Optics Interface.
In the COMSOL Multiphysics Reference Manual:
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Interference Pattern
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Optical Aberration
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Aberration Evaluation
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Ray (Plot)
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Ray Trajectories
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Filter for Ray and Ray Trajectories
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Phase Portrait
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Poincaré Map
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Ray (Data Set) and Data Sets
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Ray Evaluation and Derived Values, Evaluation Groups, and Tables
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Plot Groups and Plots