Ptychography for optical metrology with limited translation knowledge.

We introduce unknown-transverse translation diversity phase retrieval: a ptychographic algorithm for optical metrology when a subaperture is translating through a plane conjugate to the exit pupil in a very poorly known fashion. The algorithm estimates the direction of translation and the distance traveled by the subaperture from one point spread function (PSF) to the next. It also estimates unknown point target motion and rotations of the subaperture between PSF acquisitions from the PSF data.

Subaperture translation estimation accuracy in transverse translation diversity phase retrieval.

For optical metrology by transverse translation diversity phase retrieval (or ptychography), information theoretic limits on the ability to estimate subaperture translation, essential for accurate metrology, are assessed as a function of the optical aberrations of the system being measured. Special attention is given to the case that an unknown linear phase aberration, or equivalent detector or target motion, is present that varies with each point spread function in the measured data.