Open AccessReal-time label-free microscopy with adjustable phase-contrast
Author(s) -
Amber Galeana,
Rosario Porras-Aguilar
Publication year - 2020
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.398748
Subject(s) - optics , microscopy , materials science , birefringence , liquid crystal tunable filter , phase contrast imaging , differential interference contrast microscopy , contrast (vision) , optical coherence tomography , phase (matter) , optical microscope , liquid crystal , zernike polynomials , phase contrast microscopy , optoelectronics , wavefront , scanning electron microscope , physics , quantum mechanics
The lack of contrast represents a challenge in all imaging systems, including microscopy. This manuscript proposes the use of an azobenzene liquid crystal material as a Zernike filter in a phase-contrast configuration to enable label-free imaging. The novelty of the approach presented here is that it offers real-time adjustment of the contrast in images and prolonged-time observation. This is achieved with no SLM, any customized optical components, or mechanical elements, and voltage is not applied. Notably, the intensity level (0.95 mW/cm 2 ) is well below photodamage or phototoxicity for bioimaging, allowing extended time monitoring of cells. Additionally, due to the large LC's birefringence (Δn=0.2), it is possible not only to visualize a phase object but also to adjust the contrast of stainless samples by just rotating the polarization with a large and continuous dynamic range of phase retardation. In future work, this will enable a simple implementation of differential phase-contrast microscopy and quantitative phase imaging. Due to the low-intensity illumination required, this system can be combined with other imaging techniques, such as tomography and fluorescence microscopy.