Multiplexed superresolution phase microscopy with transport of intensity equation

Abstract

Resolving power in imaging systems, optical microscopy in particular, is limited by several factors being diffraction probably the most important one. Digital holographic microscopy (DHM) allows diffraction-limited quantitative phase imaging (QPI) with high accuracy by retrieving complex fields using interferometric recording, and a bunch of superresolution (SR) techniques have been widely reported through the past. However, there are additional ways to retrieve the complex amplitude distribution (such as the transport of intensity equation – TIE), having additional advantages over interferometric recording. We present how to increase the resolution limit in low/medium numerical aperture (NA) microscope objectives by using time and angular multiplexing while providing quantitative phase imaging (QPI) retrieved by TIE algorithm. This is, to the best of our knowledge, the first time that the resolution limit is experimentally improved in combination with TIE for phase retrieval in QPI. The proposed approach is validated in a real microscope embodiment (Olympus IX81) using resolution targets for quantitative resolution analysis and verifying a resolution gain factor of 2 from an experimental point of view.