We present epi-diffraction phase microscopy(epi-DPM)as a non-destructive optical method for monitoring semiconductor fabrication processes in real time and with nanometer level sensitivity.The method uses a compact M...We present epi-diffraction phase microscopy(epi-DPM)as a non-destructive optical method for monitoring semiconductor fabrication processes in real time and with nanometer level sensitivity.The method uses a compact Mach–Zehnder interferometer to recover quantitative amplitude and phase maps of the field reflected by the sample.The low temporal noise of 0.6 nm per pixel at 8.93 frames per second enabled us to collect a three-dimensional movie showing the dynamics of wet etching and thereby accurately quantify non-uniformities in the etch rate both across the sample and over time.By displaying a gray-scale digital image on the sample with a computer projector,we performed photochemical etching to define arrays of microlenses while simultaneously monitoring their etch profiles with epi-DPM.展开更多
In 1969,Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent,inhomogeneous objects.In the same era,the Wolf equations were first used to describe the ...In 1969,Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent,inhomogeneous objects.In the same era,the Wolf equations were first used to describe the propagation correlations associated with partially coherent fields.Combining these two concepts,we present Wolf phase tomography(WPT),which is a method for performing diffraction tomography using partially coherent fields.WPT reconstruction works directly in the space-time domain,without the need for Fourier transformation,and decouples the refractive index(RI)distribution from the thickness of the sample.We demonstrate the WPT principle using the data acquired by a quantitative-phase-imaging method that upgrades an existing phase-contrast microscope by introducing controlled phase shifts between the incident and scattered fields.The illumination field in WPT is partially spatially coherent(emerging from a ring-shaped pupil function)and of low temporal coherence(white light),and as such,it is well suited for the Wolf equations.From three intensity measurements corresponding to different phase-contrast frames,the 3D RI distribution is obtained immediately by computing the Laplacian and second time derivative of the measured complex correlation function.We validate WPT with measurements of standard samples(microbeads),spermatozoa,and live neural cultures.The high throughput and simplicity of this method enables the study of 3D,dynamic events in living cells across the entire multiwell plate,with an RI sensitivity on the order of 10^(−5).展开更多
Efforts to mitigate the COVID-19 crisis revealed that fast,accurate,and scalable testing is crucial for curbing the current impact and that of future pandemics.We propose an optical method for directly imaging unlabel...Efforts to mitigate the COVID-19 crisis revealed that fast,accurate,and scalable testing is crucial for curbing the current impact and that of future pandemics.We propose an optical method for directly imaging unlabeled viral particles and using deep learning for detection and classification.An ultrasensitive interferometric method was used to image four virus types with nanoscale optical path-length sensitivity.Pairing these data with fluorescence images for ground truth,we trained semantic segmentation models based on U-Net,a particular type of convolutional neural network.The trained network was applied to classify the viruses from the interferometric images only,containing simultaneously SARS-CoV-2,H1N1(influenza-A virus),HAdV(adenovirus),and ZIKV(Zika virus).Remarkably,due to the nanoscale sensitivity in the input data,the neural network was able to identify SARS-CoV-2 vs.the other viruses with 96%accuracy.The inference time for each image is 60 ms,on a common graphic-processing unit.This approach of directly imaging unlabeled viral particles may provide an extremely fast test,of less than a minute per patient.As the imaging instrument operates on regular glass slides,we envision this method as potentially testing on patient breath condensates.The necessary high throughput can be achieved by translating concepts from digital pathology,where a microscope can scan hundreds of slides automatically.展开更多
Most whole slide imaging(WSI)systems today rely on the"stop-and-stare"approach,where,at each field of view,the scanning stage is brought to a complete stop before the camera snaps a picture.This procedure en...Most whole slide imaging(WSI)systems today rely on the"stop-and-stare"approach,where,at each field of view,the scanning stage is brought to a complete stop before the camera snaps a picture.This procedure ensures that each image is free of motion blur,which comes at the expense of long acquisition times.In order to speed up the acquisition process,especially for large scanning areas,such as pathology slides,we developed an acquisition method in which the data is acquired continuously while the stage is moving at high speeds.Using generative adversarial networks(GANs),we demonstrate this ultra-fast imaging approach,referred to as GANscan,which restores sharp images from motion blurred videos.GANscan allows us to complete image acquisitions at 30x the throughput of stop-and-stare systems.This method is implemented on a Zeiss Axio Observer Z1 microscope,requires no specialized hardware,and accomplishes successful reconstructions at stage speeds of up to 5000 μm/s.We validate the proposed method by imaging H&E stained tissue sections.Our method not only retrieves crisp images from fast,continuous scans,but also adjusts for defocusing that occurs during scanning within+/-5 μm.Using a consumer GPU,the inference runs at<20 ms/image.展开更多
Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need,likely to impact various applications from biomedicine to energy conversio...Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need,likely to impact various applications from biomedicine to energy conversion.In this study,we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation,high spatial resolution,and low temporal noise.To achieve this,we advance a quantitative phase imaging system,referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation,to provide complementary maps of the optical path and electrical impedance.We demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized,semi-transparent,structured coatings involving two materials with relatively similar electrical properties.We map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as~550 nm in a titanium(dioxide)over-layer deposited on a glass support.We show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution-and beyond the limitations of electrode-based technologies(surface or scanning technologies).The findings,which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal resolutions.The virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.展开更多
Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen,e.g.,a biological cell,into brightness variations in an image.This ability to observe structures without destructive f...Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen,e.g.,a biological cell,into brightness variations in an image.This ability to observe structures without destructive fixation or staining has been widely utilized for applications in materials and life sciences.Despite these advantages,phase-contrast microscopy lacks the ability to reveal molecular information.To address this gap,we developed a bond-selective transient phase(BSTP)imaging technique that excites molecular vibrations by infrared light,resulting in a transient change in phase shift that can be detected by a diffraction phase microscope.By developing a time-gated pump-probe camera system,we demonstrate BSTP imaging of live cells at a 50 Hz frame rate with high spectral fidelity,sub-microsecond temporal resolution,and sub-micron spatial resolution.Our approach paves a new way for spectroscopic imaging investigation in biology and materials science.展开更多
The coherent interaction between an electromagnetic field and a 3D weakly scattering medium results in a simple Fourier transform relationship between the object’s structure and the complex scattered field1.As a resu...The coherent interaction between an electromagnetic field and a 3D weakly scattering medium results in a simple Fourier transform relationship between the object’s structure and the complex scattered field1.As a result,knowledge about the phase of the scattered field is necessary for solving this inverse problem with a unique solution.However,in applications,such as X-ray crystallography,typically one only has experimental access to the amplitude of the diffracted field,which results in ambiguities of the reconstruction.This century-old challenge,known as“the phase problem”2 motivated the development of computational algorithms combined with a priori knowledge about the object of interest to limit the solution space.While generally successful,this approach sometimes led to multiple solutions,i.e.,different inferred object structures for the same set of data:“Not all the guesses have been successful.This is clear,for example,from the following:Two different structures were predicted for the mineral bixbyite,one by L.Pauling,the other by W.H.Zachariasen.It is not known which,if either,is correct.”(Chapter 7 in ref.2).展开更多
In 1948,predating lasers by more than a decade,Gabor proposed a“new microscopic principle”,which was initially aimed at correcting spherical aberrations in electron microscopy1.While the method has not produced an i...In 1948,predating lasers by more than a decade,Gabor proposed a“new microscopic principle”,which was initially aimed at correcting spherical aberrations in electron microscopy1.While the method has not produced an impact in its originally intended field,it opened a new direction,known as holography,in optics.Gabor’s technique allows one to store phase information by recording on film the intensity of a field emerging at a certain distance from an object.展开更多
基金The authors thank Hoa Pham for assistance with the power spectral density calculations and Brian Cunningham,Xiuling Li,Logan Liu and Daniel Wasserman for helpful discussions. This work is supported by NSF CBET-1040462 MRI award.
文摘We present epi-diffraction phase microscopy(epi-DPM)as a non-destructive optical method for monitoring semiconductor fabrication processes in real time and with nanometer level sensitivity.The method uses a compact Mach–Zehnder interferometer to recover quantitative amplitude and phase maps of the field reflected by the sample.The low temporal noise of 0.6 nm per pixel at 8.93 frames per second enabled us to collect a three-dimensional movie showing the dynamics of wet etching and thereby accurately quantify non-uniformities in the etch rate both across the sample and over time.By displaying a gray-scale digital image on the sample with a computer projector,we performed photochemical etching to define arrays of microlenses while simultaneously monitoring their etch profiles with epi-DPM.
基金supported by the National Science Foundation(CBET0939511 STC,NRT-UtB 1735252)the National Institute of General Medical Sciences(GM129709)the National Cancer Institute(CA238191).
文摘In 1969,Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent,inhomogeneous objects.In the same era,the Wolf equations were first used to describe the propagation correlations associated with partially coherent fields.Combining these two concepts,we present Wolf phase tomography(WPT),which is a method for performing diffraction tomography using partially coherent fields.WPT reconstruction works directly in the space-time domain,without the need for Fourier transformation,and decouples the refractive index(RI)distribution from the thickness of the sample.We demonstrate the WPT principle using the data acquired by a quantitative-phase-imaging method that upgrades an existing phase-contrast microscope by introducing controlled phase shifts between the incident and scattered fields.The illumination field in WPT is partially spatially coherent(emerging from a ring-shaped pupil function)and of low temporal coherence(white light),and as such,it is well suited for the Wolf equations.From three intensity measurements corresponding to different phase-contrast frames,the 3D RI distribution is obtained immediately by computing the Laplacian and second time derivative of the measured complex correlation function.We validate WPT with measurements of standard samples(microbeads),spermatozoa,and live neural cultures.The high throughput and simplicity of this method enables the study of 3D,dynamic events in living cells across the entire multiwell plate,with an RI sensitivity on the order of 10^(−5).
基金This research is supported by National Institute of Biomedical Imaging and Bioengineering(NIBIB)supplemental grant#3R01 CA238191-02S1,National Institutes of Health(R01GM129709)National Science Foundation(0939511,1450962,1353368)(awarded to G.P.)+3 种基金EPA/USDA 2017-39591-27313(awarded to T.H.N.)National Science Foundation NSF-DMR 2004719(awarded to H.J.K.)R.B.and E.V.acknowledge the support of NSF Rapid Response Research(RAPID)grant(Award 2028431)the support of Jump Applied Research through Community Health through Engineering and Simulation(ARCHES)endowment through the Health Care Engineering Systems Center at UIUC.
文摘Efforts to mitigate the COVID-19 crisis revealed that fast,accurate,and scalable testing is crucial for curbing the current impact and that of future pandemics.We propose an optical method for directly imaging unlabeled viral particles and using deep learning for detection and classification.An ultrasensitive interferometric method was used to image four virus types with nanoscale optical path-length sensitivity.Pairing these data with fluorescence images for ground truth,we trained semantic segmentation models based on U-Net,a particular type of convolutional neural network.The trained network was applied to classify the viruses from the interferometric images only,containing simultaneously SARS-CoV-2,H1N1(influenza-A virus),HAdV(adenovirus),and ZIKV(Zika virus).Remarkably,due to the nanoscale sensitivity in the input data,the neural network was able to identify SARS-CoV-2 vs.the other viruses with 96%accuracy.The inference time for each image is 60 ms,on a common graphic-processing unit.This approach of directly imaging unlabeled viral particles may provide an extremely fast test,of less than a minute per patient.As the imaging instrument operates on regular glass slides,we envision this method as potentially testing on patient breath condensates.The necessary high throughput can be achieved by translating concepts from digital pathology,where a microscope can scan hundreds of slides automatically.
基金This work was funded bythe National Institute of Health(R01CA238191,R01GM129709)。
文摘Most whole slide imaging(WSI)systems today rely on the"stop-and-stare"approach,where,at each field of view,the scanning stage is brought to a complete stop before the camera snaps a picture.This procedure ensures that each image is free of motion blur,which comes at the expense of long acquisition times.In order to speed up the acquisition process,especially for large scanning areas,such as pathology slides,we developed an acquisition method in which the data is acquired continuously while the stage is moving at high speeds.Using generative adversarial networks(GANs),we demonstrate this ultra-fast imaging approach,referred to as GANscan,which restores sharp images from motion blurred videos.GANscan allows us to complete image acquisitions at 30x the throughput of stop-and-stare systems.This method is implemented on a Zeiss Axio Observer Z1 microscope,requires no specialized hardware,and accomplishes successful reconstructions at stage speeds of up to 5000 μm/s.We validate the proposed method by imaging H&E stained tissue sections.Our method not only retrieves crisp images from fast,continuous scans,but also adjusts for defocusing that occurs during scanning within+/-5 μm.Using a consumer GPU,the inference runs at<20 ms/image.
基金the Romanian Executive Unit for Higher Education,Research,Development and Innovation Funding for funding through Grants ERANET Euronanomed(NanoLight,135),Permed(POC4Allergies,138),ERANET-M-(SmartMatter,173)The support of the Attract project funded by the EC(HORIZON 2020-Grant Agreement no.777222)+1 种基金The support of Fonds europeen de developpement regional(FEDER)and the Walloon region under the Operational Program“Wallonia-2020.EU”(project CLEARPOWER)is gratefully acknowledged.G.P.,M.E.K.,H M,received funding from EBICS(US NSF,0939511)supported by MBM(US NSF,NRT-UtB,1735252)GP is grateful to NSF(0939511)and NIH(R01-GM129709 and R01-CA238191)。
文摘Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need,likely to impact various applications from biomedicine to energy conversion.In this study,we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation,high spatial resolution,and low temporal noise.To achieve this,we advance a quantitative phase imaging system,referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation,to provide complementary maps of the optical path and electrical impedance.We demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized,semi-transparent,structured coatings involving two materials with relatively similar electrical properties.We map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as~550 nm in a titanium(dioxide)over-layer deposited on a glass support.We show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution-and beyond the limitations of electrode-based technologies(surface or scanning technologies).The findings,which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal resolutions.The virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.
基金supported by an R01 Grant GM126049 to J.X.C.the National Science Foundation grant CBET-0939511 STC(to G.P.).
文摘Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen,e.g.,a biological cell,into brightness variations in an image.This ability to observe structures without destructive fixation or staining has been widely utilized for applications in materials and life sciences.Despite these advantages,phase-contrast microscopy lacks the ability to reveal molecular information.To address this gap,we developed a bond-selective transient phase(BSTP)imaging technique that excites molecular vibrations by infrared light,resulting in a transient change in phase shift that can be detected by a diffraction phase microscope.By developing a time-gated pump-probe camera system,we demonstrate BSTP imaging of live cells at a 50 Hz frame rate with high spectral fidelity,sub-microsecond temporal resolution,and sub-micron spatial resolution.Our approach paves a new way for spectroscopic imaging investigation in biology and materials science.
文摘The coherent interaction between an electromagnetic field and a 3D weakly scattering medium results in a simple Fourier transform relationship between the object’s structure and the complex scattered field1.As a result,knowledge about the phase of the scattered field is necessary for solving this inverse problem with a unique solution.However,in applications,such as X-ray crystallography,typically one only has experimental access to the amplitude of the diffracted field,which results in ambiguities of the reconstruction.This century-old challenge,known as“the phase problem”2 motivated the development of computational algorithms combined with a priori knowledge about the object of interest to limit the solution space.While generally successful,this approach sometimes led to multiple solutions,i.e.,different inferred object structures for the same set of data:“Not all the guesses have been successful.This is clear,for example,from the following:Two different structures were predicted for the mineral bixbyite,one by L.Pauling,the other by W.H.Zachariasen.It is not known which,if either,is correct.”(Chapter 7 in ref.2).
文摘In 1948,predating lasers by more than a decade,Gabor proposed a“new microscopic principle”,which was initially aimed at correcting spherical aberrations in electron microscopy1.While the method has not produced an impact in its originally intended field,it opened a new direction,known as holography,in optics.Gabor’s technique allows one to store phase information by recording on film the intensity of a field emerging at a certain distance from an object.
