A lens is examined with transverse ray-fan plots at three relative field heights,

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Geometrical optics and imaging · Geometrical optics and imaging

What an Instrument Can See, Ch Aberrations: the phase written on the pupil

Problem

h = 0.3, 0.6, 0.9

. In each fan the pupil coordinate is normalised to

\rho\in[-1,1]

. At the edge of the pupil (

\rho = 1

) the tangential transverse ray error is measured as

6.0\ \mu\mathrm{m}

12.0\ \mu\mathrm{m}

and

18.0\ \mu\mathrm{m}

h = 0.3, 0.6, 0.9

respectively. At

h = 0.9

, the transverse error at half the pupil radius (

\rho = 0.5

) is

4.5\ \mu\mathrm{m}

. The resulting spot diagram at each field point is comet-shaped, with its tail pointing towards the optical axis. ((a)) Identify the Seidel term responsible. ((b)) Verify its field and aperture dependence from the data.

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