Assignment 11
- Do problems 4 and 6 from section 7 of the notes..
- What is the maximum diameter a 1-meter focal length spherical
reflector may have (at infinite conjugate) without exceeding an OPD of
one-quarter wavelength (from spherical aberration) for a wavelength of
0.5 mm? What is the maximum half-field-angle
this same mirror may cover without exceeding an OPD of one-quarter
wavelength from coma?
- Given the following singlet lens description
# | rd | th | ap | rn |
1 | 48 | 3.6 | 7.5 | BK7 |
2 | -32 |
| 7.5 |
|
where ap is the aperture height, rd is the radius of curvature,
th is the center thickness, and rn is the glass.
- Enter the lens into OSLO. Replace the radius of the second surface
with a paraxial axial angle solve of -0.2. This maintains the focal
length of the lens as you vary the radius of the first surface. Find
the resulting focal length.
- Calculate the Seidel spherical
aberration as a function of the bending factor. You can do this by
varying the radius of curvature of the first surface, calculating the
spherical aberration, and then computing the bending factor from the
reported curvatures. Plot the spherical aberration as a function of
the bending factor. What lens shape minimizes the spherical
aberration?
- Find the field of view at which the spot size is
three times that on-axis at paraxial focus. You can do this by setting
a nominal field of view (say 5 degrees) and then calculating the spot
size as a function of the fractional field.
- For the lens that
minimizes spherical aberration, find the Seidel image aberrations if
the lens thickness is zero (thin lens) and compare to those for the
given lens thickness (thick lens).
- Design a thin f/16 landscape lens (zero coma and astigmatism) for a
focal length of 50 mm and half-field of view of 8-degrees. Use BK7 as
the glass. Choose a bending factor as described in the notes.
Plot the fourth-order wavefront aberrations as a function of stop
position (keeping the f/number fixed). Use this plot to determine the
optimum stop position for this landscape lens. You may use OSLO or
MATLAB to assist in the calculations.
Maintained by John Loomis,
last updated 30 Nov 2005