Optical Design Assignment 2

Use the triplet lens from Kidger, page 74-75 for first four exercises.

  1. Use MATLAB for a general raytrace of the chief ray. Compare the results to a trigonometric raytrace of the same ray. Make the chief ray pass through the center of the stop.

  2. Generate field sag curves using the Coddington raytrace in MATLAB. Modify the MATLAB code to make the chief ray pass through the center of the stop (see previous exercise).

  3. Use MATLAB to generate rays intersecting the pupil 0.1 mm away from the chief ray in the x-direction and in the y-direction. Find the distance from paraxial focus to where the y error of the meridional ray is zero and where the x error of the sagittal ray is zero. Compare these distances to the sags computed by the Coddington trace.

  4. Use MATLAB to calculate and plot a full y-fan (-1 < y < 1 with x = 0) and a full x-fan (-1 < x < 1 with y=0) starting from a full off-axis object point. Describe the symmetry (even, odd, or none) of each plot. Plot both x-errors and y-errors, if non-zero.

  5. Write a MATLAB script or function to flip a lens description. This can be useful to generating starting points for optimization.

  6. Write a merit function for an achromatic doublet which generates two defects: spherical aberration for green wavelength and zero difference in spherical aberration between green and red (or blue) wavelengths. The variables are the curvatures of the two lenses. Plot contours of zero defects vs the two curvatures.

  7. Write a MATLAB program to determine the powers of a thin-lens triplet apochromat (no airspaces) such that the focal length of green light is 50 mm and the focal lengths of red and blue equal the focal length of green. Use the aprochromat examples of ZEMAX to help pick suitable sets of three glasses.

  8. Write a MATLAB program to deterine if the shapes of the three lens above can be set to produce zero spherical aberration in green, and zero difference in spherical aberration between green and red and between green and blue. Try producing a movie of contours with two curvatures shown and the remaining curvature varying with time.

Maintained by John Loomis, last updated 16 June 2009