Page 191 - Modern Optical Engineering The Design of Optical Systems
P. 191
174 Chapter Eight
ANSWER: (a) 10 millidiopters = 0.010 diopter. The focal length is equal to
1/0.010 = 100 m. (b) Using Eq. 3.25, (n 1) (c c ) assuming that c is
1 2 2
zero, solving for c and inverting to get R , we get
1 1
R f (n 1) 100 0.6 60 m.
1
(c) The sagittal height of a sphere is approximately SH y /2R 10 /120,000
2
2
0.000833 mm. This is equal to 0.000833/0.000550 1.515 wavelengths. Since
we get one fringe for each half wavelength, there will be 3.03 fringes.
