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Using the cutoff radial scan

The cutoff radial scan displays a graph of cutoff angle as a functioni of field position. Rays leaving the field point at a larger angle are outside the pupil.

The cutoff radial scan is presently only available for finite-conjugate systems (i.e., with the object surface a finite distance from the lens).

To create the cutoff radial scan window:

  1. Select from the menu Analysis > Energy > Capture

Exporting data from cutoff radial scan

The underlying data may be exported using the Export toolbar icon, or by "Save data as..." on the contextual menu (obtained by control clicking on the image).

Options panel

Direction
Using the Direction popup menu, select the direction of the pupil scan. For example, "+y pupil scan" starts in the center of the pupil and scans radially in the y direction until the edge of the pupil is encountered.
Wave
Using the Wave popup menu, select the wave for which you wish to calculate.
Number of field values
Number of points in the field of view at which the scan will be performed. The calculation time is proportional to this number.
Color by
Use this popup to indicate how curves will be colored.
Pupil coordinate tolerance
Convergence criterion when zeroing in on the edge of the pupil. In reduced pupil units.
Scan to pupil coordinate
Used to specify how far out to scan. Should be set larger than 1 so that the edge of the pupil will be found even when it is outside the paraxial pupil edge.
Paraxial trace
If checked, all rays will be traced paraxially. Only useful for diagnostic purposes.
Scale only expands
If checked, the scale of the axes only expands due to the action of sliders, etc.
Axis tight on data
If checked, the limits of the axes are chosen so that the data exactly fills the graph. If not checked the limits of the axes are chosen to give "nice" values at the extremes of the axes.
Plot momentum
If checked, transverse ray momentum is plotted instead of pupil coordinate. In this case there is also the option to plot in "mrad" (1000 times momentum).
Surface
The surface popup allows you to select a surface that rays much reach to be considered "through the pupil". Normally this is the image surface.

See also