Quadriwave lateral shearing interferometry for quantitative phase microscopy of living cells

TLDR

Phase imaging using a high‑resolution wavefront sensor is explored. The study explains the measurement technology and its implementation on a conventional microscope, focusing on how a non‑spatially coherent source affects phase‑image signal‑to‑noise ratio. The technique employs a quadriwave lateral shearing interferometer mounted on a standard transmission white‑light microscope, analyzed through wave‑optics and geometrical‑optics frameworks. Measurements of phase shifts in microscopic beads and giant unilamellar vesicles confirm the method’s accuracy, and diffraction‑limited images of living COS‑7 cells reveal membrane and organelle dynamics.

Abstract

Phase imaging with a high-resolution wavefront sensor is considered. This is based on a quadriwave lateral shearing interferometer mounted on a non-modified transmission white-light microscope. The measurement technology is explained both in the scope of wave optics and geometrical optics in order to discuss its implementation on a conventional microscope. In particular we consider the effect of a non spatially coherent source on the phase-image signal-to-noise ratio. Precise measurements of the phase-shift introduced by microscopic beads or giant unilamellar vesicles validate the principle and show the accuracy of the methods. Diffraction limited images of living COS-7 cells are then presented, with a particular focus on the membrane and organelle dynamics.