Structured illumination multimodal 3D-resolved quantitative phase and fluorescence sub-diffraction microscopy

• Published in: Biomedical optics express Vol. 8; no. 5; pp. 2496 - 2518
• Main Authors: Chowdhury, Shwetadwip, Eldridge, Will J, Wax, Adam, Izatt, Joseph A
• Format: Journal Article
• Language: English
• Published: United States Optical Society of America 01.05.2017
• Subjects: (100.6640) Superresolution; (180.6900) Three-dimensional microscopy
• ISSN: 2156-7085; 2156-7085
• DOI: 10.1364/boe.8.002496

Sub-diffraction resolution imaging has played a pivotal role in biological research by visualizing key, but previously unresolvable, sub-cellular structures. Unfortunately, applications of far-field sub-diffraction resolution are currently divided between fluorescent and coherent-diffraction regimes, and a multimodal sub-diffraction technique that bridges this gap has not yet been demonstrated. Here we report that structured illumination (SI) allows multimodal sub-diffraction imaging of both coherent quantitative-phase (QP) and fluorescence. Due to SI's conventionally fluorescent applications, we first demonstrate the principle of SI-enabled three-dimensional (3D) QP sub-diffraction imaging with calibration microspheres. Image analysis confirmed enhanced lateral and axial resolutions over diffraction-limited QP imaging, and established striking parallels between coherent SI and conventional optical diffraction tomography. We next introduce an optical system utilizing SI to achieve 3D sub-diffraction, multimodal QP/fluorescent visualization of A549 biological cells fluorescently tagged for F-actin. Our results suggest that SI has a unique utility in studying biological phenomena with significant molecular, biophysical, and biochemical components.