Fourier phase microscopy with white light

Abstract

Laser-based Fourier phase microscopy (FPM) works on the principle of decomposition of an image field in two spatial components that can be controllably shifted in phase with respect to each other. However, due to the coherent illumination, the contrast in phase images is degraded by speckles. In this paper we present FPM with spatially coherent white light (wFPM), which offers high spatial phase sensitivity due to the low temporal coherence and high temporal phase stability due to common path geometry. Further, by using a fast spatial light modulator (SLM) and a fast scientific-grade complementary metal oxide semiconductor (sCMOS) camera, we report imaging at a maximum rate of 12.5 quantitative phase frames per second with 5.5 mega pixels image size. We illustrate the utility of wFPM as a contrast enhancement as well as dynamic phase measurement method by imaging section of benign colonic glands and red blood cell membrane fluctuation.

Extension of the concept of an anomalous water component to images of T-cell organelles

“…The raster method of image recording was used in contrast to the studies that employed the multistep method. [12][13][14][15] New physical parameters of TC organelles (the phase volume, exclusion zone areas, phase thickness, and RIs profiles) were obtained using our originally developed algorithms.…”

“…Common for all interference methods is the representation of the images in the form of a two-dimensional distribution hðx; yÞ of optical path difference (OPD) in the image plane. The most important and the unique advantage of the interference microscopy is the measurement of OPD in absolute units of wavelength [7][8][9][10][11][12][13][14][15][16][17][18][19] with a very high precision, which is hardly achievable or is even impossible with other methods. Normally, the phase image is described as the function hðx; yÞ ¼ Z ðnðx; y; zÞ − n 0 Þdz in the image plane ðx; yÞ, where nðx; y; zÞ and n 0 are the refractive indices of the object and the environment, respectively.…”

“…This also applies to cell images obtained by various interference microscopy methods; no effect of 4-water on the images has been reported. [12][13][14][15] Quantitative analysis of phase images of various cell types [7][8][9][10][11][12] has shown that the changes in their optical parameters caused by external factors cannot be solely explained by alterations of their proteins. In solving this problem, we suggested [7][8][9][10][11][12] that not only the change in protein RI averaged by the cell volume should be taken into account, but the possibility that the RI of intracellular water is changed should also be assumed.…”

One Type of Bio-Phase Microscopy Imaging Method Based on a Con Beam with Double Dove Prisms

“…In 2012, Samsheerali [15] reported a coaxial phase-shift digital holographic technology with the help of a diffraction grating phase, which realized the high stability of the quantitative phase imaging. In recent years, other QPI based on the coaxial interference microscopy [16][17][18][19][20][21][22][23][24] have also been put forward, such as the Popescu team [17] successively put forward Fourier Phase Microscopy (FPM) and space optical interference microscopy (SLIM) [20][21][22][23] and the Wax team put forward parallel two-steps phase-shift Microscopy [24], and so on. The research of these techniques have greatly enriched coaxial interference method, make the technology more and more high, but its structure and operation is becoming more and more complicated.…”

Enhanced quantitative phase imaging in self-interference digital holographic microscopy using an electrically focus tunable lens

“…Thus, many attempts for capturing digital holograms with low-coherent light sources (LCLS) [8][9][10][11][12][13][14][15][16][17] or by using laser light with reduced coherence, for example, generated by a rotating diffusor [18] were reported. Other approaches have been described in which a reduction of speckle noise is achieved by recording multiple off-axis holograms at different polarizations of object and reference wave in combination with subsequently averaging of the reconstructed amplitude distributions [19].…”