• Relation between refractive angle 0 of a prism and least deviation
angle a:
sin a+0
0
2 — n sin 2 '
where n is the refractive index of the prism.
• Equation of spherical mirror:
-t--—
s
s
= R '
where R is the curvature radius of the mirror.
• Equations for aligned optical system (Fig. 5.2):
n'
n
f'
xe= fr.
S, s
s
s
Fig. 5.2.
• Relations between focal lengths and optical power:
n'
f'
re
f ' =
f
71 —
(1) '
W '
f
•
• Optical power of a spherical refractive surface:
n'
R
n
•
(5.1i)
• Optical power of a thin lens in a medium with refractive index no:
(n— no) ( -1 4-37
,
(5.1j)
where n is the refractive index of the lens.
• Optical power of a thick lens:
0=01+02 — n 0102,
(5.1k)
(5.1e)
(5.1f)
(5.1g)
(5.1h)
where d is the thickness of the lens. This equation is also valid for a system of
two thin lenses separated by a medium with refractive index n.