Wavefront Microscopy Using Quadriwave Lateral Shearing Interferometry: From Bioimaging to Nanophotonics

Common cameras are only sensitive to the intensity of light, discarding an essential feature of a light wave: its phase profile or, equivalently, its wavefront profile. This Review focuses on a rising wavefront imaging technique called quadriwave lateral shearing interferometry (QLSI), based on the simple use of a 2-dimensional diffraction grating, aka a cross-grating, in front of a regular camera. We detail the working principle of QLSI and its implementation on an optical microscope. We highlight its microscopy applications in bioimaging and nanophotonics, in particular for the characterization of living cells, nanoparticles, 2D materials, metasurfaces, microscale temperature gradients, and surface topography. Finally, we draw a critical comparison of QLSI with current quantitative phase microscopy techniques, namely, digital holography microscopy (DHM), spatial light interference microscopy (SLIM), and diffraction phase microscopy (DPM).

Automated summary

This Review discusses a cutting-edge wavefront imaging technique called quadriwave lateral shearing interferometry (QLSI) that utilizes a 2-dimensional diffraction grating in front of a regular camera. The working principle and implementation of QLSI on an optical microscope are detailed. The microscopy applications of QLSI in bioimaging and nanophotonics for the characterization of various samples are highlighted. A critical comparison between QLSI and current quantitative phase microscopy techniques is also presented.