Optical Design Study 6

Aspheric Systems

  1. Design an f/2 singlet lens with focal length of 50 mm using one aspheric surface. Use the conic constant and two curvatures to control spherical aberration, coma, and focal length. Optimize for monochromatic operation at 632.8 nm and 0.5 degree half field of view. Use three fields for optimization (0, 0.1, and 0.5 degree). Provide a listing of fabrication data, including the aspheric sag table with best-fitting-sphere enabled.

  2. Layout a two mirror system with an effective focal length of 100 mm, a mirror separation of 20 mm, a back focal distance of 30 mm, and a half field-of-view of 0.5 degree. Use three fields for optimization (0, 0.1, and 0.5 degree).

    1. Primary elliptical, secondary is spherical (Dall-Kirkham). Use ZEMAX optimizer to choose the conic constant of the primary.

    2. Primary parabolic, secondary hyperbolic (Cassegrain). Use ZEMAX to choose the conic constant.

    3. Optimize the conic constant of both mirrors (Richey-Chretien).

You can obtain diffraction-limited performance on-axis by setting the number of fields to one, and re-optimizing on-axis. Otherwise you will obtain a compromise between on-axis and off-axis performance. There is no control over astigmatism on any of these systems, so the useful field of view is small.

For each system, provide

  1. a full listing of surface data
  2. a drawing of the system
  3. rms spot size vs. field
  4. ray fans
  5. field plot
  6. spot diagrams at the best focal plane. Be sure to document the rms spot sizes.
  7. spot diagrams through focus.
  8. MTF plots at all fields.

Maintained by John Loomis, last updated 7 July 2012