Article
Optics
Ksenia Abrashitova, Lyubov V. Amitonova
Summary: Light is used as a tool for various metrology applications and fiber probes are widely used to deliver light to hard-to-reach places. The integration of optical metrology into a flexible fiber probe has resulted in the development of a multimode fiber ruler for detecting nanometric displacements. The ruler demonstrates high resolving power and does not require detailed field mapping or special structures.
Article
Nanoscience & Nanotechnology
Zachary H. Levine, Bradley K. Alpert, Amber L. Dagel, Joseph W. Fowler, Edward S. Jimenez, Nathan Nakamura, Daniel S. Swetz, Paul Szypryt, Kyle R. Thompson, Joel N. Ullom
Summary: This article presents three-dimensional reconstructions of a region of an integrated circuit using x-ray computed tomography. The reconstructions are based on measurements obtained with a new high-magnification x-ray microscope. This innovative instrument generates x-rays in a 100 nm spot using a focused electron beam and employs energy-resolving x-ray detectors to minimize background noise and potentially identify materials within the sample. The reconstructions are consistent with the circuit's design file.
MICROSYSTEMS & NANOENGINEERING
(2023)
Article
Mathematics
Gbenga O. Ojo, Nazim I. Mahmudov
Summary: This paper presents a new approximate analytical method for solving the fractional biological population model, based on the Aboodh transform method and a new iterative method. Illustrative cases are considered for comparison between exact and numerical solutions for different values of alpha, with surface plots provided to understand the effect of the fractional order. The method is efficient, accurate, and easy to implement with less computational effort.
Article
Optics
Jialin Zhang, Runnan Zhang, Long Tian, Zhenwei Xie, Jiasong Sun, Shijun Zhu, Xiaocong Yuan, Qian Chen, Chao Zuo
Summary: We derive the complete form of the transport of intensity equation (TIE) for arbitrary wave fields, including the effect of optical vortices. To overcome the difficulty of phase retrieval using near-field intensity measurements, a hard-edged aperture is introduced to break the azimuthal symmetry of wave propagation and visualize the rotation of the local Poynting vector. The new version of TIE is developed for phase retrieval of wave fields with optical vortices, and experimental demonstration using Laguerre-Gaussian vortex beams is presented.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Optics
Nolan Peard, Kartik Ayyer, Henry N. Chapman
Summary: Second-order intensity correlations can reveal the Fourier transform modulus, but phase retrieval via third-order intensity correlations has been limited to special emitter configurations. This paper describes a general method for ab initio phase retrieval via intensity triple correlations, enabling accurate phase retrieval for arbitrary arrays of incoherent emitters. This method could be applied to imaging stars or fluorescent atoms and molecules. With this work, it is now finally possible to perform Fourier inversion directly and reconstruct images of arbitrary arrays of independent emitters via far-field intensity correlations alone.
Article
Optics
Abhijit Roy
Summary: A technique based on intensity basis addition of two speckle patterns with polarization diversity is proposed. It is shown that by tuning the polarization diversity, a complete control over the spatial coherence of the superposed speckle pattern can be achieved. The modulation of spatial coherence depends not only on the polarization vectors of the constituent speckle patterns, but also on the sum of the polarization orientations, especially if the original field is not completely depolarized. The potential application of this work is in biomedical imaging, where speckle noise reduction is important.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Physics, Multidisciplinary
Deming Peng, Xuan Zhang, Yonglei Liu, Yimeng Zhu, Yahong Chen, Fei Wang, Yangjian Cai
Summary: This study demonstrates that the hidden image information behind a random scattering medium can be encoded in the complex spatial coherence structure of a partially coherent light beam. Experimental validation shows that the image information can be successfully recovered using spatial coherence measurement and an iterative phase retrieval algorithm. The reconstructed image not only captures the spatial shape but also provides information about the position, including lateral shift and longitudinal distances.
FRONTIERS IN PHYSICS
(2022)
Article
Optics
Haowen Zhou, Elena Stoykova, Mallik Hussain, Partha P. Banerjee
Summary: This paper examines the performance of direct and unwrapped phase retrieval combining digital holography with the transport of intensity. It explores digital holography with transport of intensity for inline and off-axis geometries, introduces phase-shifting digital holography with transport of intensity, and compares the accuracy of phase retrieval as well as computational speeds with traditional techniques.
Article
Optics
Lin Zhang, Huijuan Zhao, Zhongxing Zhou, Mengyu Jia, Limin Zhang, Jingying Jiang, Feng Gao
Summary: The study introduces a new algorithm for X-ray phase-contrast computed tomography, which improves spatial resolution and reduces noise level by using weighted sum and iterative algorithms during the reconstruction process. Simulation and experimental results demonstrate the superiority of the proposed strategy over conventional methods in terms of image quality evaluations.
Article
Optics
Boyu Gu, Yuhua Zhang
Summary: By constructing a wavefront reconstructor with a damped transpose matrix of the influence function and using an integral control strategy, we tested its performance in an experimental system consisting of an adaptive optics scanning laser ophthalmoscope and an adaptive optics near-confocal ophthalmoscope. The results showed that this reconstructor could ensure a stable and precise correction for wavefront aberration compared to a conventional optimal reconstructor formed by the inverse matrix of the influence function. This method may provide a helpful tool for testing, evaluating, and optimizing adaptive optics systems.
PHOTONICS RESEARCH
(2022)
Article
Engineering, Electrical & Electronic
Sanjeev Kumar, Manjunatha Mahadevappa, Pranab Kumar Dutta
Summary: The article presents a lensless microscopy technique using a spatially extended white LED with low spatial and very low temporal coherence as the light source. By decomposing the convolution operation, the number of unknown parameters to be estimated is drastically reduced, leading to an improvement in resolution.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2021)
Article
Mathematics, Applied
Joshua Warigue Ndiaye
Summary: In this paper, the system of Schrodinger equations on conical spaces is investigated. The iterative reconstruction algorithms for two average Schrodinger functionals are rewritten and their convergence is proven. Furthermore, asymptotic pointwise error estimates are provided for both algorithms when the average samples are corrupted by noise.
ANALYSIS AND MATHEMATICAL PHYSICS
(2022)
Article
Optics
Asemare Mengistie Taddese, Nicolas Verrier, Matthieu Debailleul, Jean-Baptiste Courbot, Olivier Haeberle
Summary: The study analyzed the effect of sample scanning patterns on Fourier space filling for a transmission setup and found that 3D uniform angular sweeping best fills the Fourier space, leading to better quality images.
Article
Engineering, Electrical & Electronic
Lisa Krainz, Ekaterina Sherina, Simon Hubmer, Mengyang Liu, Wolfgang Drexler, Otmar Scherzer
Summary: Optical coherence elastography (OCE) is a promising research field for visualizing micro-scale tissue stiffness changes. This study compares three different reconstruction methods for accurately determining Young's modulus, with the image-based inverse reconstruction method (IIM) showing the best performance.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Optics
Seungri Song, Jeongsoo Kim, Taegyun Moon, Baekcheon Seong, Woovin Kim, Chang-Hyuk Yoo, Jun-Kyu Choi, Chulmin Joo
Summary: Optical anisotropy is an intrinsic property of many materials that originates from the structural arrangement of molecular structures. Various polarization-sensitive imaging methods have been developed to investigate anisotropic materials, but most of them are not suitable for three-dimensional imaging of multiple scattering samples. In this study, we propose a novel reference-free computational imaging technique, polarization-sensitive intensity diffraction tomography (PS-IDT), that enables the reconstruction of 3D anisotropy distribution of both weakly and multiple scattering specimens from multiple intensity-only measurements. We demonstrate the capabilities of PS-IDT by presenting 3D anisotropy maps of various samples.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Colum M. O'Leary, Benedikt Haas, Christoph T. Koch, Peter D. Nellist, Lewys Jones
Summary: The article presents an extension of existing STEM distortion correction techniques for the treatment of 4D data series, demonstrating improvements in spatial fidelity, signal-to-noise ratio (SNR), phase precision, and spatial resolution using electron ptychography and electric-field mapping as model cases.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Georg Schoenweger, Adrian Petraru, Md Redwanul Islam, Niklas Wolff, Benedikt Haas, Adnan Hammud, Christoph Koch, Lorenz Kienle, Hermann Kohlstedt, Simon Fichtner
Summary: This paper presents the first in-depth structural and electrical characterization of all-epitaxial, all-wurtzite-type ferroelectric III-N semiconductor heterostructures. The results show that Al1-xScxN films have multiple strain states and exhibit splitting of the ferroelectric displacement current into separate peaks. It is also observed that films grown on the metal-polar GaN template feature an initial multidomain state.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Yuhang Zhao, Radwan M. Sarhan, Alberto Eljarrat, Zdravko Kochovski, Christoph Koch, Bernd Schmidt, Wouter Koopman, Yan Lu
Summary: Bimetallic nanostructures can generate a new type of photo-enhanced nanoreactors by utilizing photo-generated heat to accelerate catalytic reactions. The study demonstrates that the photothermal conversion of Au-Pd nanorods can be improved by coating with polydopamine or TiO2, resulting in increased reaction rates.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Nitu Syed, Alastair Stacey, Ali Zavabeti, Chung Kim Nguyen, Benedikt Haas, Christoph T. Koch, Daniel L. Creedon, Enrico Della Gaspera, Philipp Reineck, Azmira Jannat, Matthias Wurdack, Sarah E. Bamford, Paul J. Pigram, Sherif Abdulkader Tawfik, Salvy P. Russo, Billy J. Murdoch, Kourosh Kalantar-Zadeh, Chris F. McConville, Torben Daeneke
Summary: In this study, ultrathin indium nitride nanosheets were synthesized using a liquid metal-based printing method and a microwave plasma-enhanced nitridation reaction. The nanosheets exhibited high carrier mobilities and quantized states, making them promising for applications in optoelectronic devices and 2D heterostructures.
Article
Chemistry, Multidisciplinary
Denis Yagodkin, Kyrylo Greben, Alberto Eljarrat Ascunce, Sviatoslav Kovalchuk, Mahdi Ghorbani-Asl, Mitisha Jain, Silvan Kretschmer, Nikolai Severin, Juergen P. Rabe, Arkady Krasheninnikov, Christoph T. Koch, Kirill Bolotin
Summary: A new localized excitonic state is demonstrated in patterned monolayer 2D semiconductors. The state is distinguished by non-linear power dependence and can survive up to room temperature. It is shown to be of extrinsic origin, likely associated with charge transfer excitons from the organic substance deposited onto the 2D semiconductor.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Matthias Scheffler, Martin Aeschlimann, Martin Albrecht, Tristan Bereau, Hans-Joachim Bungartz, Claudia Felser, Mark Greiner, Axel Gross, Christoph T. Koch, Kurt Kremer, Wolfgang E. Nagel, Markus Scheidgen, Christof Woell, Claudia Draxl
Summary: Achievements in condensed matter physics, chemistry, and materials science greatly influence the prosperity and lifestyle of our society, as new materials are crucial for various sectors. However, the value of the enormous amount of research data produced in these fields can only be realized through the establishment of a FAIR data infrastructure, allowing for comprehensive characterization and sharing of the data to advance science.
Article
Chemistry, Multidisciplinary
Dongjiu Xie, Yaolin Xu, Yonglei Wang, Xuefeng Pan, Eneli Hark, Zdravko Kochovski, Alberto Eljarrat, Johannes Muller, Christoph T. Koch, Jiayin Yuan, Yan Lu
Summary: This article introduces a method for synthesizing heteroatom-doped carbon materials using poly(ionic liquid) as precursors. Polydopamine coating and ion exchange were used to successfully apply imidazolium-based poly(ionic liquid) nanovesicles in morphology-maintaining carbonization, preparing carbon composite nanocapsules. The strategy was further extended to synthesize carbon composite nanocapsules functionalized with iron nitride nanoparticles. This well-crafted composite nanostructure effectively mitigated the shuttle effect of lithium polysulfides in Li-S batteries, showing excellent electrochemical performance.
Article
Chemistry, Multidisciplinary
Kate Reidy, Paulina Ewa Majchrzak, Benedikt Haas, Joachim Dahl Thomsen, Andrea Konecna, Eugene Park, Julian Klein, Alfred J. H. Jones, Klara Volckaert, Deepnarayan Biswas, Matthew D. Watson, Cephise Cacho, Prineha Narang, Christoph T. Koch, Soren Ulstrup, Frances M. Ross, Juan Carlos Idrobo
Summary: The integration of metallic contacts with 2D semiconductors can significantly affect the local optoelectronic properties. In this study, we analyze the local excitonic changes in a 2D semiconductor MoS2 in contact with Au. Our findings suggest that the observed changes are due to the dielectric screening of the excitonic Coulomb interaction, and increasing the van der Waals distance can optimize excitonic spectra in mixed-dimensional interfaces.
Article
Nanoscience & Nanotechnology
Thorsten Schultz, Max Kneiss, Philipp Storm, Daniel Splith, Holger von Wenckstern, Christoph T. Koch, Adnan Hammud, Marius Grundmann, Norbert Koch
Summary: In this study, it is found through simulations that the detection wavelength range of GaAs/AlxGa1-xAs quantum well infrared photodetectors (QWIPs), which are currently state-of-the-art, can be substantially improved using kappa-([Al,In](x)Ga1-x)(2)O-3, while being transparent to visible light and insensitive to photon noise due to its wide band gap. It is also demonstrated that the efficiency of QWIPs critically depends on the quantum well thickness, making precise control and determination of the thickness essential.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Daniel Abou-Ras, Ulrike Bloeck, Sebastian Caicedo-Davila, Alberto Eljarrat, Hannah Funk, Adnan Hammud, Sinju Thomas, Dan R. Wargulski, Thomas Lunkenbein, Christoph T. Koch
Summary: This passage presents a practical tutorial on the application of correlative microscopy in optoelectronic semiconductor materials and devices. It discusses the combination of electron microscopy, scanning probe microscopy, and light microscopy for analyzing material and device properties. The tutorial also covers specimen preparation and demonstrates the ability of electron microscopy to monitor phase segregation processes in semiconductor nanoparticles and thin films, along with the explanation of algorithms for extracting phase information.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Benedikt Haas, Tara M. Boland, Christian Elsaesser, Arunima K. Singh, Katia March, Juri Barthel, Christoph T. Koch, Peter Rez
Summary: Phonon scattering at grain boundaries plays a crucial role in controlling the thermal conductivity of nanoscale devices. This study uses monochromated electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) to measure the 60 meV optic mode at grain boundaries in silicon at atomic resolution. The results show the existence of localized phonon modes and support the idea that grain boundaries can act as waveguides.
Article
Microscopy
Christoph T. Koch
Summary: Solving crystal structures from kinematical X-ray or electron diffraction patterns of single crystals requires recording more diffracted beams than the number of atoms in the structure. This method utilizes the fact that multiple scattering encodes structure factor phases in the diffracted intensities to solve the crystallographic phase problem. The retrieval of both amplitudes and phases of electron structure factors from diffraction patterns recorded with varying angle of incidence will be demonstrated, making it potentially useful for electron crystallography of beam-sensitive complex structures.
Article
Multidisciplinary Sciences
Marcel Schloz, Johannes Mueller, Thomas C. Pekin, Wouter Van den Broek, Jacob Madsen, Toma Susi, Christoph T. Koch
Summary: We propose a method for reducing the dose required for electron ptychographic reconstruction by adaptively scanning the specimen, providing spatial information redundancy in important regions. The method is based on a deep learning model trained by reinforcement learning using prior knowledge from training data. We demonstrate that adaptive scanning in electron ptychography outperforms alternative low-dose ptychography experiments in terms of reconstruction resolution and quality.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
David Burmeister, Alberto Eljarrat, Michele Guerrini, Eva Rock, Julian Plaickner, Christoph T. Koch, Natalie T. Banerji, Caterina Cocchi, Emil J. W. List-Kratochvil, Michael J. Bojdys
Summary: Graphitic carbon nitrides are promising materials for overcoming the limitations of 0D molecular and 1D polymer semiconductors due to their covalently-bonded, layered, and crystalline structure. This study investigates the structural, vibrational, electronic, and transport properties of poly(triazine-imide) (PTI) derivatives with and without intercalated ions. It is found that PTI nano-crystals exhibit high charge carrier density and THz conductivity, but the electroluminescence from the pi-pi* transition is quenched, limiting their use in electroluminescent devices. Macroscopic charge transport in PTI films is also hindered by disorder at crystal-crystal interfaces.
Article
Materials Science, Multidisciplinary
Wahib Aggoune, Alberto Eljarrat, Dmitrii Nabok, Klaus Irmscher, Martina Zupancic, Zbigniew Galazka, Martin Albrecht, Christoph Koch, Claudia Draxl
Summary: The perovskite barium stannate (BaSnO3) shows promise for electronic applications due to its transparency and high room-temperature mobility. A combined theoretical and experimental study provides a consistent picture of its electronic structure and optical excitations.
COMMUNICATIONS MATERIALS
(2022)
Article
Microscopy
C. Gao, C. Hofer, T. J. Pennycook
Summary: Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, contrast reversals can occur when the projected potential becomes strong. Recent research has shown that these reversals can be counteracted by adapting the focus. This study explains why the best contrast is often found with the probe focused to the middle of the sample and highlights the importance of convergence angle in thin samples to remove contrast reversals.
Article
Microscopy
J. Lindner, U. Ross, T. Meyer, V. Boureau, M. Seibt, Ch. Jooss
Summary: Phase-shifting electron holography is an excellent method with high phase sensitivity to reveal electron wave phase information. An advanced drift correction scheme is proposed in this study, which exploits the interface of the TEM specimen and the vacuum area in the hologram. This method allows for obtaining reliable phase information.
Article
Microscopy
Ali Jaberi, Nicolas Brodusch, Jun Song, Raynald Gauvin
Summary: This study investigates knock-on damage in lithium-ion batteries (LIBs) by computing threshold displacement energies (TDEs) and performing Monte Carlo simulation. The results indicate that Li is most sensitive to knock-on damage at moderate electron energies, and TDE is the principal parameter for assessing Li sensitivity to knock-on damage across similar structures.
Article
Microscopy
Alexander Schroeder, Christopher Rathje, Leon van Velzen, Maurits Kelder, Sascha Schaefer
Summary: This study utilizes novel event-based electron detector platforms to extend the temporal resolution of electron microscopy. By training a neural network to predict electron arrival time, the researchers were able to improve the timing accuracy and achieve a promising solution for enhancing electron timing precision in various electron microscopy applications.
Article
Microscopy
Avi Auslender, Nivedita Pandey, Amit Kohn, Oswaldo Dieguez
Summary: This article describes a faster implementation based on DFT for computing the mean inner potential of crystals, providing quantum-mechanical calculations beyond the independent-atom approximation. The study also reveals the dependence of the mean inner potential on sample boundary conditions, mass density, and magnetic susceptibility, highlighting its correlation with various material properties.
Article
Microscopy
Zhidong Yang, Dawei Zang, Hongjia Li, Zhao Zhang, Fa Zhang, Renmin Han
Summary: In this work, we propose a self-supervised deep learning model for cryo-ET volumetric image denoising based on noise modeling and sparsity guidance. Experimental results demonstrate that our method can achieve reliable denoising by training on single noisy volume and outperform existing methods.
Article
Microscopy
J. Kuttruff, J. Holder, Y. Meng, P. Baum
Summary: In this study, a robust clustering algorithm is proposed that can find clusters in a continuous stream of raw data in real time. This algorithm converts pixel hits measured by hybrid pixel detectors to real single-electron events. By continuously comparing with previous hits, the algorithm efficiently identifies the merging of new and old events.
Article
Microscopy
D. G. Senturk, C. P. Yu, A. De Backer, S. Van Aert
Summary: This article presents a statistics-based method for accurately counting the number of atoms in nanostructures, especially for images acquired with low electron doses and multiple element structures.
Article
Microscopy
Mauricio J. Prieto, Lucas de Souza Caldas, Liviu C. Tanase, Thomas Schmidt, Oscar Rodriguez de la Fuente
Summary: This study presents a synchrotron-based investigation of the synthesis process of a magnetite/hematite bilayer. Ion bombardment gradually transforms hematite into magnetite, and the growth of magnetite leads to the formation of stable boundaries. These findings are significant for understanding novel oxide heterostructures.
Article
Microscopy
Emre Yoruk, Holger Klein, Stephanie Kodjikian
Summary: Beam sensitive nanomaterials pose challenges for crystallographic structure determination. A dose symmetric electron diffraction tomography (DS-EDT) method is developed to reduce beam damage and obtain complete data sets by merging individual datasets from multiple crystals.
Article
Microscopy
A. Pofelski, Y. Zhu, G. A. Botton
Summary: The precision and sensitivity of the GPA method for strain characterization is a widely discussed topic. This study introduces the concept of phase noise and analyzes the parameter of sampling to improve the precision of GPA. Experimental and theoretical results demonstrate that using a larger pixel spacing in STEM can enhance the precision and sensitivity of the GPA method.
Article
Microscopy
Sangjun Kang, Di Wang, Christian Kuebel, Xiaoke Mu
Summary: Transmission electron microscopy is a valuable tool for assessing strain fields within materials. However, using thin specimens in TEM analysis can affect atomic configuration and deformation structure.
