Quantitative phase imaging with partially coherent illumination

Nguyen, Tuan Hung; Edwards, Chris; Goddard, Lynford L.; Popescu, Gabriel

doi:10.1364/ol.39.005511

Cited by 64 publications

(44 citation statements)

References 32 publications

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“…The typical dominant wavelength of this LED is 623 nm, and the spectral bandwidth at half maximum intensity is 18 nm. The partially coherent feature of the light source helps mitigate speckle noise resulting from parasitic reflections inside the optics and specimens 12, 13 . Then the light beam is spatially filtered by a combination of a pinhole with a diameter of 100 μm and two lenses L1, L2 to generate a plane wave probe.…”

Section: Methodsmentioning

confidence: 99%

“…By introducing partially coherent light source such as LED to avoid speckle noise, the accuracy and signal-to-noise ratio (SNR) of the TIE technique can be improved and the root-mean-square (RMS) error of the reconstructed phase image will decrease to 12% 12 . Nevertheless, its accuracy still need to be improved if compared with interferometric methods like diffraction phase microscope (DPM) 1, 13–15 , digital holographic microscope (DHM) 16–21 and the off-axis τ interferometer 22, 23 . For measurement precision, the interferometric technique is now able to reach an optical path stability of about 10 pm with an Adimec camera having larger pixel full well capacity 24 .…”

Section: Introductionmentioning

confidence: 99%

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Quadriwave lateral shearing interferometric microscopy with wideband sensitivity enhancement for quantitative phase imaging in real time

Ling

Jiang

Zhang

et al. 2017

Sci Rep

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Real-time quantitative phase imaging has tremendous potential in investigating live biological specimens in vitro.Here we report on a wideband sensitivity-enhanced interferometric microscopy for quantitative phase imaging in real time by employing two quadriwave lateral shearing interferometers based on randomly encoded hybrid gratings with different lateral shears. Theoretical framework to analyze the measurement sensitivity is firstly proposed, from which the optimal lateral shear pair for sensitivity enhancement is also derived. To accelerate the phase retrieval algorithm for real-time visualization, we develop a fully vectorized path-independent differential leveling phase unwrapping algorithm ready for parallel computing, and the framerate for retrieving the phase from each pair of two 4 mega pixel interferograms is able to reach 47.85 frames per second. Experiment results demonstrate that the wideband sensitivity-enhanced interferometric microscopy is capable of eliminating all the periodical error caused by spectral leaking problem and reducing the temporal standard deviation to the half level compared with phase directly retrieved by the interferogram. Due to its high adaptability, the wideband sensitivity-enhanced interferometric microscopy is promising in retrofitting existing microscopes to quantitative phase microscopes with high measurement precision and real-time visualization.Quantitative phase microscopy (QPM), which provides additional phase information about the refractive index distribution of transparent specimens, has drawn much attention in both optical and biomedical research. The main advantage of quantitative phase microscopy (QPM) over conventional intensity imaging or fluorescence microscopy is that it is label-free and no dye or fluorescent protein is required to enhance the contrast of the microscopic image, which makes it possible to study live biological specimens in vitro [1][2][3][4][5] . Ptychography 5-8 is one of the emerging QPM techniques that can retrieve the phase and amplitude of the scattered wavefield when a coherent illumination beam passes through the specimen under test. The diffraction patterns of the specimen are captured by a CCD camera and the phase retrieval algorithm is carried out based on the extended ptychographic iterative engine (ePIE). Ptychographic microscope can obtain high contrast images free of halo artefact using low magnification microscopic objectives 9, 10 . However, both the acquisition for the tile scan to generate overlapping diffraction patterns and the computation of the ePIE algorithm takes a relatively long time, so it is currently not available to real-time applications. Different from ptychography, the transport-of-intensity equation (TIE) technique employs focus and defocus images to retrieve the phase variation of the wavefront. It can be applied to a conventional intensity microscope directly and the acquisition rate can be set up to 15Hz if an electrically tunable fluidic lens is employed to vary the equivalent focal length of the opt...

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quadriwave lateral shearing interferometric microscopy with wideband sensitivity enhancement for quantitative phase imaging in real time

Ling

Jiang

Zhang

et al. 2017

Sci Rep

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“…Clearly, the effects of phase underestimation and “halo effect”, which are well-known in phase contrast microscopy925, can be seen directly from Eq. (4).…”

Section: Resultsmentioning

confidence: 99%

Halo-free Phase Contrast Microscopy

Nguyen

Kandel

Shakir

et al. 2017

Sci Rep

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We present a new approach for retrieving halo-free phase contrast microscopy (hfPC) images by upgrading the conventional PC microscope with an external interferometric module, which generates sufficient data for reversing the halo artifact. Acquiring four independent intensity images, our approach first measures haloed phase maps of the sample. We solve for the halo-free sample transmission function by using a physical model of the image formation under partial spatial coherence. Using this halo-free sample transmission, we can numerically generate artifact-free PC images. Furthermore, this transmission can be further used to obtain quantitative information about the sample, e.g., the thickness with known refractive indices, dry mass of live cells during their cycles. We tested our hfPC method on various control samples, e.g., beads, pillars and validated its potential for biological investigation by imaging live HeLa cells, red blood cells, and neurons.

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“…For getting images and investigation of phase objects there are different optical contrast techniques, such as phase contrast microscopy, interference microscopy, diffraction phase microscopy, holographic microscopy, and etc. [1][2][3][4] All quantitative phase imaging techniques can be divided into two groups, which are traditional interferometry techniques and common-path ones. In the traditional interferometry methods the reference field interfere with the field, scattered on the object, and the result of interference is recorded on the detector.…”

Section: Introductionmentioning

confidence: 99%

“…This group of techniques includes phase contrast microscopy, diffraction phase microscopy, spatial light interference microscopy, Fourier phase microscopy and etc. [1][2][3][4][5][6][7] One of these techniques -phase contrast microscopy or Zernike method is based on spatial filtration of the optical field by introducing the phase delay between unscattered wave and wave, which is scattered on the research object. In all phase contrast methods there is a transformation of phase signal into intensity or amplitude modulation, detected by the photosensitive detector.…”

Section: Introductionmentioning

confidence: 99%

Parameter optimization of phase microscope with the interferometer as a spatial phase modulator

Izotova

Ryabukho

2015

SPIE Proceedings

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Spatial light interference microscopy (SLIM) is the optical method for visualization cell structure and measurement its dynamics. The distinctive feature of SLIM technique is introducing the additional spatial phase modulation of optical field in system of phase contrast microscope. In the currently known optical schemes of phase microscope the additional phase modulation is created by the liquid crystal spatial phase modulator (LCPM). It produces the phase shifts to the π/2, introducing the phase contrast between undiffracted and diffracted light from the sample. In our work we use the Michelson interferometer type optical system for introducing the phase delay between two waves. The phase shift is produced by micro displacement of one of the mirrors of the interferometer with the help of the piezoelectric element. Such modification allows setting the path difference of fraction of the wavelength between the undiffracted and diffracted components of the optical field, so it's possible to get quantitative phase image of the object. This modernization of standard scheme of SLIM improves its performance due to higher speed of piezoelectric element comparing with speed of LCPM. The quality of result images of the investigated object depend on technical parameters of the optical scheme of microscope, including the size of illumination system aperture diaphragm. The purpose of this work is to investigate the influence of the aperture diaphragm on the phase image quality of RBC, which will be used further for the measurement RBC parameters and its dynamics.

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Quantitative phase imaging with partially coherent illumination

Cited by 64 publications

References 32 publications

Quadriwave lateral shearing interferometric microscopy with wideband sensitivity enhancement for quantitative phase imaging in real time

Quadriwave lateral shearing interferometric microscopy with wideband sensitivity enhancement for quantitative phase imaging in real time

Halo-free Phase Contrast Microscopy

Parameter optimization of phase microscope with the interferometer as a spatial phase modulator

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