We provide new expressions for equations that were incorrectly presented in a recent paper [Opt. Express 18, 656 (2010)].
© 2010 OSA
In our recent paper , we described in Eq. (3) a defocus phase function S(ρ) that included two constants M and N. The expressions for the constants, as presented in Eqs. (4) and (5) were incorrect. The correct expressions are:
The modified spherical aberration function SA is then obtained as:
where x is chosen to minimise the RMS value of SA. We note that the other results presented in the paper were not affected by this editing error.