Phase-edge imaging using q-plate shifts for faster and simpler microscopy

TL;DR

This paper introduces a simplified, faster method for phase-edge imaging in microscopy using fewer q-plate shifts, reducing measurements and enhancing speed while effectively isolating phase edges.

Contribution

The authors develop a reduced-shift q-plate technique that halves measurement requirements, simplifying phase-edge imaging and potentially doubling acquisition speed in microscopy.

Findings

Achieved up to 97.6% amplitude-edge reduction.

Correlation coefficients up to 0.78 and 0.75 in experiments.

Method reduces measurement count by half, enabling faster imaging.

Abstract

We present a simplified method for isolating the edges of a phase object from the edges of an amplitude object using a 4f system with an off-axis q-plate. Instead of the four off-axis shifts of the q-plate required in previous work, we need only two shifts (along +/- x) combined with linear polarizers at 45 degrees and 135 degrees. The number of measurements is reduced by half, potentially doubling the acquisition speed. We derive the theoretical basis, showing that the resulting intensity corresponds to the phase gradient squared, with amplitude-object contributions eliminated. Experiments on two phase-amplitude object samples demonstrate amplitude-edge reduction up to 97.6% and correlation coefficients up to 0.78 (sample 1) and 0.75 (sample 2). In overlapping regions, the phase edge is partially recovered; full recovery would require additional processing such as inverse filtering. This research is useful for biological imaging applications where fast and simple phase-edge isolation is desired.