scholarly journals The effect of pupil transmittance on axial resolution of reflection phase microscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Gyu Hyeon ◽  
Kwanjun Park ◽  
Taeseok Daniel Yang ◽  
Taedong Kong ◽  
Beop-Min Kim ◽  
...  
Keyword(s):  
Diffraction Limit ◽  
Objective Lens ◽  
Limit Set ◽  
Axial Resolution ◽  
Experimental Conditions ◽  
Phase Microscopy ◽  
Reflection Phase ◽  
Gating Mechanism ◽  
Practical Limit

AbstractA reflection phase microscope (RPM) can be equipped with the capability of depth selection by employing a gating mechanism. However, it is difficult to achieve an axial resolution close to the diffraction limit in real implementation. Here, we systematically investigated the uneven interference contrast produced by pupil transmittance of the objective lens and found that it was the main cause of the practical limit that prevents the axial resolution from reaching its diffraction limit. Then we modulated the power of illumination light to obtain a uniform interference contrast over the entire pupil. Consequently, we could achieve an axial resolution fairly close to the diffraction limit set by the experimental conditions.

scholarly journals Single-shot Full-field reflection phase microscopy

2011 ◽  
Vol 19 (8) ◽  
pp. 7587 ◽  
Author(s):  
Zahid Yaqoob ◽  
Toyohiko Yamauchi ◽  
Wonshik Choi ◽  
Dan Fu ◽  
Ramachandra R. Dasari ◽  
...  
Keyword(s):  
Single Shot ◽  
Full Field ◽  
Phase Microscopy ◽  
Reflection Phase

scholarly journals Reflection phase microscopy using spatio-temporal coherence of light

Optica ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 1468 ◽  
Author(s):  
Youngwoon Choi ◽  
Poorya Hosseini ◽  
Jeon Woong Kang ◽  
Sungsam Kang ◽  
Taeseok Daniel Yang ◽  
...  
Keyword(s):  
Temporal Coherence ◽  
Phase Microscopy ◽  
Reflection Phase ◽  
Spatio Temporal

scholarly journals Estimation of temperature rise at the focus of objective lens at the 1700 nm window

2017 ◽  
Vol 10 (02) ◽  
pp. 1650048 ◽  
Author(s):  
Ping Qiu ◽  
Runfu Liang ◽  
Jiexing He ◽  
Ke Wang
Keyword(s):  
Water Absorption ◽  
Temperature Rise ◽  
Biological Tissues ◽  
Objective Lens ◽  
Experimental Conditions ◽  
Two Photon Microscopy ◽  
Small Water ◽  
Two Photon ◽  
Tissue Scattering ◽  
Order Of Magnitude

Optical microscopy of biological tissues at the 1700[Formula: see text]nm window has enabled deeper penetration, due to the combined advantage of relatively small water absorption and tissue scattering at this wavelength. Compared with excitation at other wavelengths, such as the commonly used 800[Formula: see text]nm window for two-photon microscopy, water absorption at the 1700[Formula: see text]nm window is more than one order of magnitude higher. As a result, more temperature rise can be expected and can be potentially detrimental to biological tissues. Here, we present theoretical estimation of temperature rise at the focus of objective lens at the 1700[Formula: see text]nm window, purely due to water absorption. Our calculated result shows that under realistic experimental conditions, temperature rise due to water absorption is still below 1[Formula: see text]K and may not cause tissue damage during imaging.

scholarly journals A comparative study of X-ray tomographic microscopy on shales at different synchrotron facilities: ALS, APS and SLS

2012 ◽  
Vol 20 (1) ◽  
pp. 172-180 ◽  
Author(s):  
Waruntorn Kanitpanyacharoen ◽  
Dilworth Y. Parkinson ◽  
Francesco De Carlo ◽  
Federica Marone ◽  
Marco Stampanoni ◽  
...  
Keyword(s):  
Data Quality ◽  
Light Source ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Three Dimensional ◽  
Objective Lens ◽  
Low Density ◽  
Experimental Conditions ◽  
X Ray ◽  
Volume Fractions

Synchrotron radiation X-ray tomographic microscopy (SRXTM) was used to characterize the three-dimensional microstructure, geometry and distribution of different phases in two shale samples obtained from the North Sea (sample N1) and the Upper Barnett Formation in Texas (sample B1). Shale is a challenging material because of its multiphase composition, small grain size, low but significant amount of porosity, as well as strong shape- and lattice-preferred orientation. The goals of this round-robin project were to (i) characterize microstructures and porosity on the micrometer scale, (ii) compare results measured at three synchrotron facilities, and (iii) identify optimal experimental conditions of high-resolution SRXTM for fine-grained materials. SRXTM data of these shales were acquired under similar conditions at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory, USA, the Advanced Photon Source (APS) of Argonne National Laboratory, USA, and the Swiss Light Source (SLS) of the Paul Scherrer Institut, Switzerland. The data reconstruction of all datasets was handled under the same procedures in order to compare the data quality and determine phase proportions and microstructures. With a 10× objective lens the spatial resolution is approximately 2 µm. The sharpness of phase boundaries in the reconstructed data collected from the APS and SLS was comparable and slightly more refined than in the data obtained from the ALS. Important internal features, such as pyrite (high-absorbing), and low-density features, including pores, fractures and organic matter or kerogen (low-absorbing), were adequately segmented on the same basis. The average volume fractions of low-density features for sample N1 and B1 were estimated at 6.3 (6)% and 4.5 (4)%, while those of pyrite were calculated to be 5.6 (6)% and 2.0 (3)%, respectively. The discrepancy of data quality and volume fractions were mainly due to different types of optical instruments and varying technical set-ups at the ALS, APS and SLS.

scholarly journals Dynamic speckle illumination wide-field reflection phase microscopy

2014 ◽  
Vol 39 (20) ◽  
pp. 6062 ◽  
Author(s):  
Youngwoon Choi ◽  
Poorya Hosseini ◽  
Wonshik Choi ◽  
Ramachandra R. Dasari ◽  
Peter T. C. So ◽  
...  
Keyword(s):  
Wide Field ◽  
Phase Microscopy ◽  
Reflection Phase ◽  
Dynamic Speckle

scholarly journals Routine sub-2.5 Å cryo-EM structure determination of B-family G protein-coupled receptors

2020 ◽  
Author(s):  
Radostin Danev ◽  
Matthew Belousoff ◽  
Yi-Lynn Liang ◽  
Xin Zhang ◽  
Denise Wootten ◽  
...  
Keyword(s):  
G Protein ◽  
Structure Determination ◽  
G Protein Coupled Receptors ◽  
Objective Lens ◽  
Phase Plate ◽  
Performance Limits ◽  
Experimental Conditions ◽  
Structure Based Drug Design ◽  
Depth Analysis ◽  
G Protein Coupled

AbstractCryo-electron microscopy (cryo-EM) experienced game-changing hardware and software advances about a decade ago. Since then, there have been gradual and steady improvements in experimental and data analysis methods. Nonetheless, structural analysis of nonsymmetric membrane proteins, such as G protein-coupled receptors (GPCRs), remains challenging. Their relatively low molecular weight and obstruction by the micelle/nanodisc result in marginal signal levels, which combined with the intrinsic flexibility of such complexes creates difficult structural study scenarios. Pushing the performance limits of cryo-EM requires careful optimization of all experimental aspects. To this end, it is necessary to build quantitative knowledge of the effect each parameter has on the outcome. Here, we present in-depth analysis of the influence of the main cryo-EM experimental factors on the performance for GPCR structure determination. We used a tandem experiment approach that combined real-world structural studies with parameter testing. We quantified the effects of using a Volta phase plate, zero-loss energy filtering, objective lens aperture, defocus magnitude, total exposure, and grid type. Through such systematic optimization of the experimental conditions, it has been possible to routinely determine class B1 GPCR structures at resolutions better than 2.5 Å. The improved fidelity of such maps helps to build higher confidence atomic models and will be crucial for the future expansion of cryo-EM into the structure-based drug design domain. The optimization guidelines drafted here are not limited to GPCRs and can be applied directly for the study of other challenging membrane protein targets.

scholarly journals Effect of spatial spectrum overlap on Fourier ptychographic microscopy

2017 ◽  
Vol 10 (02) ◽  
pp. 1641004 ◽  
Author(s):  
Qiulan Liu ◽  
Cuifang Kuang ◽  
Yue Fang ◽  
Peng Xiu ◽  
Yicheng Li ◽  
...  
Keyword(s):  
Imaging Technique ◽  
Computing Time ◽  
Spatial Spectrum ◽  
Diffraction Limit ◽  
Optimal Choice ◽  
Synthetic Aperture ◽  
Objective Lens ◽  
Coherent Imaging ◽  
Optical Components ◽  
Imaging Performance

Fourier ptychographic microscopy (FPM) is a newly developed imaging technique which stands out by virtue of its high-resolution and wide FOV. It improves a microscope’s imaging performance beyond the diffraction limit of the employed optical components by illuminating the sample with oblique waves of different incident angles, similar to the concept of synthetic aperture. We propose to use an objective lens with high-NA to generate oblique illuminating waves in FPM. We demonstrate utilizing an objective lens with higher NA to illuminate the sample leads to better resolution by simulations, in which a resolution of 0.28[Formula: see text][Formula: see text]m is achieved by using a high-NA illuminating objective lens (NA[Formula: see text][Formula: see text]) and a low-NA collecting objective lens (NA[Formula: see text][Formula: see text]) in coherent imaging ([Formula: see text][Formula: see text]nm). We then deeply study FPM’s exact relevance of convergence speed to spatial spectrum overlap in frequency domain. The simulation results show that an overlap of about 60% is the optimal choice to acquire a high-quality recovery (520*520 pixels) with about 2 min’s computing time. In addition, we testify the robustness of the algorithm of FPM to additive noises and its suitability for phase objects, which further proves FPM’s potential application in biomedical imaging.

Simulation of Magnetic Induction Mapping in the TEM

1997 ◽  
Vol 3 (S2) ◽  
pp. 1157-1158
Author(s):  
J. Dooley ◽  
M. De Graef
Keyword(s):  
Objective Lens ◽  
Magnetic Storage ◽  
Experimental Conditions ◽  
Storage Devices ◽  
Lorentz Microscopy ◽  
Full Characterization ◽  
Thin Foils ◽  
Free Region ◽  
High Resolution Tem ◽  
Field Free Region

The design of modern magnetic storage devices with their rapidly increasing information density ne-cessitates a full characterization of the underlying microstructure of the device materials. Lorentz microscopy has for several decades been the main vehicle for micro-magnetic observations. The pri-mary limitation of the Lorentz modes is perhaps the attainable magnification. To avoid saturation, the sample must be placed in a low-field or preferably field-free region in the column, and this invariably means that the microscope can only be operated at low magnifications. Both Fresnel and Foucault images are rather sensitive to the exact experimental conditions which renders quantitative observa-tions quite difficult, if not impossible. Inelastic scattering further limits the usefulness of Lorentz observations to very thin foils.We have recently reported1 a novel Lorentz microscopy setup, combining a Gatan Imaging Filter (GIF) and a JEOL 4000EX top-entry high resolution TEM, operated at 400 kV with the main objective lens switched off.

scholarly journals Reflection Phase Microscopy by Successive Accumulation of Interferograms

ACS Photonics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 757-766
Author(s):  
Min Gyu Hyeon ◽  
Taeseok Daniel Yang ◽  
Jin-Sung Park ◽  
Kwanjun Park ◽  
Yong Guk Kang ◽  
...  
Keyword(s):  
Phase Microscopy ◽  
Reflection Phase
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