Geometric-Phase Microscopy for Quantitative Phase Imaging of Isotropic, Birefringent and Space-Variant Polarization Samples

Petr Bouchal,Zbyněk Dostál,Lenka Štrbková,Radim Chmelík,Zdeněk Bouchal

doi:10.1038/s41598-019-40441-9

Abstract

We present geometric-phase microscopy allowing a multipurpose quantitative phase imaging in which the ground-truth phase is restored by quantifying the phase retardance. The method uses broadband spatially incoherent light that is polarization sensitively controlled through the geometric (Pancharatnam-Berry) phase. The assessed retardance possibly originates either in dynamic or geometric phase and measurements are customized for quantitative mapping of isotropic and birefringent samples or multi-functional geometric-phase elements. The phase restoration is based on the self-interference of polarization distinguished waves carrying sample information and providing pure reference phase, while passing through an inherently stable common-path setup. The experimental configuration allows an instantaneous (single-shot) phase restoration with guaranteed subnanometer precision and excellent ground-truth accuracy (well below 5 nm). The optical performance is demonstrated in advanced yet routinely feasible noninvasive biophotonic imaging executed in the automated manner and predestined for supervised machine learning. The experiments demonstrate measurement of cell dry mass density, cell classification based on the morphological parameters and visualization of dynamic dry mass changes. The multipurpose use of the method was demonstrated by restoring variations in the dynamic phase originating from the electrically induced birefringence of liquid crystals and by mapping the geometric phase of a space-variant polarization directed lens.

Highlights

Www.nature.com/scientificreports transport of intensity equation[13] or techniques of conventional and Fourier ptychographic microscopy utilizing the phase-retrieval algorithms[14]
The multipurpose use of quantitative 4G optics microscopy (Q4GOM) is demonstrated by quantitative noninvasive imaging of live cells, restoration of the dynamic phase retardance originating from birefringence of liquid crystals and complete quantitative mapping of geometric-phase holograms[5]
Experimental data were obtained in the setup composed of the add-on 4G optics module connected to the interference microscope (Fig. 1a) using the polarization adapted MMO (Fig. 1b)

Summary

Introduction

Www.nature.com/scientificreports transport of intensity equation[13] or techniques of conventional and Fourier ptychographic microscopy utilizing the phase-retrieval algorithms[14]. The most important property of the geometric-phase elements is their polarization sensitivity allowing to impose phase changes of the opposite sign on the light with left-/right-handed circular polarization (LHCP/RHCP)[5,6] This capability was used to design optically thick and physically thin light shaping components such as sub-wavelength gratings[17], polarization directed lenses and prisms[4] or complex geometric-phase holograms[5]. The geometric-phase QPI platform, here referred to as quantitative 4G optics microscopy (Q4GOM), was developed as an incoherent achromatic imaging technique allowing the instantaneous (single-shot) restoration of the phase retardance introduced in either dynamic or geometric phase. This capability makes Q4GOM powerful and versatile. The multipurpose use of Q4GOM is demonstrated by quantitative noninvasive imaging of live cells, restoration of the dynamic phase retardance originating from birefringence of liquid crystals and complete quantitative mapping of geometric-phase holograms[5]

Methods

Results

Discussion

Conclusion