Zernike Mirror Source Modification
Although it is possible to apply an arbitrary wavefront deformation to a source definition, the ability to supply the deformation as a set of Zernike terms is not a built in functionality. One trick for quickly applying a Zernike wavefront deformation to a source node is shown in the image below (and example file), where a plane wave source node is configured so that it propagates along the -Z axis. The rays will then reflect off of a Zernike mirror surface and continue propagating along the +Z axis with 2X the deformation applied to the Zernike mirror surface.
When configuring the Zernike mirror surface, as shown below, be sure to set the Zernike Normalization Aperture to match the radius of the source aperture, which is 5 mm in this example (also be sure to set the coating and raytrace property to Reflect and Reflect Specular, respectively). Note that half a wave of Z1 (Tilt along X) and half a wave of Z7 (3rd order Coma along X) have been applied to the mirror surface, which will result in 1 wave each upon reflection.
To view the resulting wavefront after reflecting off the mirror, perform the following steps:
- Go to Raytrace > Trace and Render
- Go to Analyses > Coherent Scalar Wave Field
- In the resulting plot, right mouse click in the main plot window and choose "Show Computed Wavefront"
- Right mouse click in the wavefront plot and choose, "Decompose Wavefront".
- Set the Aperture radius to 5 in X and Y and set the Max Term Number to 11. Hit OK.
The resulting wavefront plot, with ~4 waves P-V deformation, is shown below.
The decomposition of the wavefront prints the first 11 Zernike coefficients to the output window. Note that the Z1 and Z7 terms are approximately 1 wave and that the other terms are non-zero, which is the result of the numeric overlap integral between the Zernike terms and the coherent field on the rectilinear grid of the analysis surface.
FRED Example File: ZernikeMirrorSource.frd