Midterm exam OPTI 518 Spring 2012
You can use a computer, a calculator, your class summary, and your class notes.
75 minutes.
In answering the questions below write down the pertinent formulas and show how you use them to do the calculations. Each question is worth 10 points for a total of 120.
Do labeled nice graphs and sketches whenever asked.
1)Draw the wavefans for a system having 2 waves of spherical aberration and two waves for coma aberration. Draw the sagittal and tangential fans for the zero field position and for the full field position.
2)Write down the sag equation to fourth-order for a spherical surface a radius r and semi-aperture y.
3)Write down the relationship between a change of focus and the longitudinal change . For a f/10 system with , what is ? The wavelength is 0.0005 mm.
4)What are the radii of curvature of a thin lens that has zero coma aberration and zero astigmatism? The focal length is 100 mm, the object is at infinity, the lens works at F/10, the lens index of refraction is n=1.5, and the wavelength is 0.0005 mm.
5)For the lens in problem 4 what is the amount of spherical aberration contributed?
6)For the lens in problem 4 where is the stop?
7)For the lens in problem 4 design an aspheric surface on a parallel glass plate that corrects only for spherical aberration. This aspheric plate has zero optical power. Where should the aspheric plate be located? and what is the sag of the aspheric plate? Assume the index of the plate to be n=1.5. Sketch the system.
8)For the system in problem 7) (aspheric plate and lens) the field of view is 15 degrees. What is the image height?
9)For the system in problem 7) (aspheric plate and lens) what is the chromatic change of focus. Assume that the V-number is 64 for both the plate and the lens.
10)For the system in problem 7) (aspheric plate and lens) what is the chromatic change of magnification. Assume that the V-number is 64 for both the plate and the lens.
11)For the system in problem 7) (aspheric plate and lens) what is the Petzval radius?
12)For the system in problem 7) add a field flattener lens to correct for field curvature. What is the power of the field flattening lens? Sketch the plate, lens and field flattener system.