The digital hologram to the right was produced by a grey-scale
adaptation of the
Low-Tec shareware program
The positions of the source and single refracting point used to produce the hologram are shown in yellow.
The source wavelength was equal to one pixel-width so you can see some digital granularity in the image. (Anyone who happened to run the hologram program prior to 23 April 2001 may have noticed that the variable wavelength function did not work.)