The Zernike polynomials are a set of orthogonal polynomials that arise in the expansion of a wavefront function for optical systems with circular pupils. The odd and even Zernike polynomials are given by
| (1) |
where the radial function is defined for
and
integers with
by
| (2) |
Here, is the azimuthal angle with
and
is the radial distance with
(Prata and Rusch 1989). The even and odd polynomials are sometimes also denoted
| (3) | |||
| (4) |
Zernike polynomials are implemented in the Wolfram Language as ZernikeR[n, m, rho].
Other closed forms for include
| (5) |
for odd and
, where
is the gamma function and
is a hypergeometric function. This can also be written in terms of the Jacobi polynomial
as
| (6) |
The first few nonzero radial polynomials are
| (7) | |||
| (8) | |||
| (9) | |||
| (10) | |||
| (11) | |||
| (12) | |||
| (13) | |||
| (14) | |||
| (15) |
(Born and Wolf 1989, p. 465).
The radial functions satisfy the orthogonality relation
| (16) |
where is the Kronecker delta, and are related to the Bessel function of the first kind by
| (17) |
(Born and Wolf 1989, p. 466). The radial Zernike polynomials have the generating function
| (18) |
(correcting the typo of Born and Wolf) and are normalized so that
| (19) |
(Born and Wolf 1989, p. 465).
The Zernike polynomials also satisfy the recurrence relations
| (20) |
(Prata and Rusch 1989). The coefficients and
in the expansion of an arbitrary radial function
in terms of Zernike polynomials
| (21) |
are given by
| (22) |
where
| (23) |
Let a "primary" aberration be given by
| (24) |
with and where
is the complex conjugate of
, and define
| (25) |
giving
| (26) |
Then the types of primary aberrations are given in the following table (Born and Wolf 1989, p. 470).
| aberration | |||||
| spherical aberration | 0 | 4 | 0 | ||
| coma | 0 | 3 | 1 | ||
| astigmatism | 0 | 2 | 2 | ||
| field curvature | 1 | 2 | 0 | ||
| distortion | 1 | 1 | 1 |