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Terahertz chiral photonic-crystal cavities with broken time-reversal symmetry

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arXiv 2024年

作者： Tay, Fuyang Sanders, Stephen Baydin, Andrey Song, Zhigang Welakuh, Davis M. Alabastri, Alessandro Rokaj, Vasil Dag, Ceren B. Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX77005 United States Smalley–Curl Institute Rice University HoustonTX77005 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02139 United States Max Planck Institute for The Structure and Dynamics of Matter Luruper Chaussee 149 Hamburg22761 Germany ITAMP Harvard-Smithsonian Center for Astrophysics CambridgeMA02138 United States Department of Physics Harvard University CambridgeMA02138 United States Department of Physics Villanova University VillanovaPA19085 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Strong coupling between matter and vacuum electromagnetic fields in a cavity can induce novel quantum phases in thermal equilibrium via symmetry breaking. Particularly, coupling with circularly polarized fields can break time-reversal symmetry, leading to topological modifications in the band structure. Therefore, chiral optical cavities that host chiral vacuum fields are being sought, especially in the terahertz (THz) frequency range, where various large-oscillator-strength resonances exist. Here, we present a novel approach to achieving THz chiral photonic-crystal cavities (PCCs) with high-quality factors (>400) using a magnetoplasma in a lightly doped semiconductor. Numerical simulations of an optimized structure based on InSb in a small perpendicular magnetic field (∼0.2 T) show chiral cavity resonances with near-perfect ellipticity at the surfaces of the central dielectric layer, where one can place atomically thin materials like monolayer graphene. We theoretically estimate an energy gap on the order of 1 meV in graphene when coupled to our proposed chiral cavity, which is potentially measurable in experiments. These THz chiral PCCs offer a promising platform for exploring new phases in cavity-dressed condensed matter with broken time-reversal symmetry. Copyright © 2024, The Authors. All rights reserved.

关键词： Crystal symmetry

Simple Switched-Inductor High-Gain Boost converter

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Simple Switched-Inductor High-Gain Boost converter

International Symposium on Power Electronics, electrical Drives, Automation and Motion, SPEEDAM

作者： Alireza Siadatan Sahar Tahzibi Reza Babaloo Jacob Gotlieb Energy Systems Group The Edward S. Rogers Sr. Department of Electrical and Computer Engineering Faculty of Applied Science and Engineering University of Toronto Toronto ON Canada Electrical Engineering Group Department of Electronics Information and Bioengineering (DEIB) Industrial and information Engineering school Polytechnic University of Milan Milan Italy Department of Electrical & Computer Engineering University of British Columbia Vancouver BC Canada

ISBN: (数字)9781728170190

ISBN: (纸本)9781728170206

Due to the environmental concerns, renewable energy sources such as photovoltaic (PV) are turned into a promising way to supply humans' energy demand. Despite considerable improvements in this field, there are still some barriers hindering swift growth of technology. Low output voltage is one of the main challenges. Since grid as well as most of the energy consumers requires higher voltage than output voltage of a PV panel, it is inevitable to utilize high step-up dc/dc converters as an interface. In this paper, one simple boost converter topology based on the switched-inductor concept is introduced. The proposed topology has high voltage gain, a great output voltage flexibility, and the ability to reduce the input voltage ripple. Due to its modular structure, different output voltages can be provided just by increasing the number of boosting cells. The proposed topology is analyzed and simulation results are provided to verify the converter performance.

关键词： Switches Capacitors Topology Photovoltaic systems DC-DC power converters

Photonic Crystal Enhanced Fluorescence with DNA-based Nano-gripper for Ultrasensitive Intact Viral Pathogen Biosensing 22

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Photonic Crystal Enhanced Fluorescence with DNA-based Nano-g...

Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XXII 2025

作者： Xiong, Yanyu Zhou, Lifeng Cooper, Laura Zheng, Mengxi Shepherd, Skye Dwivedy, Abhisek Song, Tingjie Hong, Wei Chen, Xin Liu, Shengyan Le, Linh T.P. Umrao, Saurabh Rong, Lijun Wang, Tong Wang, Xing Cunningham, Brian T. Department of Electrical and Computer Engineering Holonyak Micro and Nanotechnology Laboratory University of Illinois at Urbana-Champaign UrbanaIL61801 United States Carl R. Woese Institute for Genomic Biology University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Microbiology and Immunology College of Medicine University of Illinois at Chicago ChicagoIL60612 United States Department of Chemistry University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Bioengineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States Center for Biophysics and Quantitative Biology University of Illinois at Urbana-Champaign United States Advanced Science Research Center at Graduate Center City University of New York New YorkNY10031 United States Cancer Center at Illinois University of Illinois at Urbana-Champaign UrbanaIL61801 United States

ISBN: (纸本)9781510684188

We introduce a novel biosensing approach that utilizes photonic crystal-enhanced fluorescence technology integrated with a bioinspired DNA origami NanoGripper, selectively generating a fluorescent signal only upon detecting intact viral pathogens. Using intact SARS-CoV-2 as a representative example of a respiratory virus, this method demonstrates rapid, ultrasensitive, and highly selective biosensing. Photonic crystals (PC), serving as dielectric microcavities, provide substantial local field enhancement, far-field directional emission, large Purcell factors, and high quantum efficiency. These novel origami probes are coupled with a Photonic Crystal Enhanced Fluorescence Microscope, achieving a 10,000-fold signal enhancement compared to traditional single fluorophore reporters on glass substrates. Unlike surface-based ELISA assays, the capture reaction between the NanoGripper and the SARS-CoV-2 virus occurs in solution, reaching equilibrium within 10 minutes. After mixing, the mixture is pulled down to the PC surface for signal enhancement and direct counting. With virtually zero off-target signals, we achieve a limit of detection (LoD) of 100 viral genome copies per mL in human saliva, enabling ultra-high detection sensitivity. © 2025 SPIE.

关键词： Coronavirus

Endotaxial Stabilization of 2D Charge Density Waves with Long-range Order

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arXiv 2023年

作者： Sung, Suk Hyun Agarwal, Nishkarsh Baggari, Ismail El Goh, Yin Min Kezer, Patrick Schnitzer, Noah Liu, Yu Lu, Wenjian Sun, Yuping Kourkoutis, Lena F. Heron, John T. Sun, Kai Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Rowland Institute Harvard University CambridgeMA02142 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States Department of Electrical and Computer Engineering University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering Cornell University IthacaNY14853 United States Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei230031 China High Magnetic Field Laboratory Chinese Academy of Sciences Hefei230031 China Collaborative Innovation Centre of Advanced Microstructures Nanjing University Nanjing210093 China School of Applied and Engineering Physics Cornell University IthacaNY14853 United States Kavli Institute Cornell for Nanoscale Science IthacaNY14853 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Physics University of Michigan Ann ArborMI48109 United States

Charge density waves are emergent quantum states that spontaneously reduce crystal symmetry, drive metal-insulator transitions, and precede superconductivity. In low-dimensions, distinct quantum states arise, however, thermal fluctuations and external disorder destroy long-range order. Here we stabilize ordered two-dimensional (2D) charge density waves through endotaxial synthesis of confined monolayers of 1T-TaS2. Specifically, an ordered incommensurate charge density wave (oIC-CDW) is realized in 2D with dramatically enhanced amplitude and resistivity. By enhancing CDW order, the hexatic nature of charge density waves becomes observable. Upon heating via in-situ TEM, the CDW continuously melts in a reversible hexatic process wherein topological defects form in the charge density wave. From these results, new regimes of the CDW phase diagram for 1T-TaS2 are derived and consistent with the predicted emergence of vestigial quantum order. © 2023, CC BY.

关键词： Charge density waves

Nematoelasticity of hybrid molecular-colloidal liquid crystals

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Physical Review E 2021年第1期104卷 014703-014703页

作者： B. Senyuk H. Mundoor I. I. Smalyukh H. H. Wensink Department of Physics University of Colorado Boulder Colorado 80309 USA Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado Boulder Colorado 80309 USA Chemical Physics Program Departments of Chemistry and Physics University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA Laboratoire de Physique des Solides Université Paris-Saclay & CNRS UMR 8502 91405 Orsay France

Colloidal rods immersed in a thermotropic liquid-crystalline solvent are at the basis of so-called hybrid liquid crystals, which are characterized by tunable nematic fluidity with symmetries ranging from conventional uniaxial nematic or antinematic to orthorhombic [Mundoor et al., science 360, 768 (2018)]. We provide a theoretical analysis of the elastic moduli of such systems by considering interactions between the individual rods with the embedding solvent through surface-anchoring forces, as well as steric and electrostatic interactions between the rods themselves. For uniaxial systems, the presence of colloidal rods generates a marked increase of the splay elasticity, which we found to be in quantitative agreement with experimental measurements. For orthorhombic hybrid liquid crystals, we provide estimates of all 12 elastic moduli and show that only a small subset of those elastic constants play a relevant role in describing the nematoelastic properties. The complexity and possibilities related to identifying the elastic moduli in experiments are briefly discussed.

关键词： Biaxial liquid crystals Liquid crystals

Detection of Toxic Contaminants in Alcohol-Based Hand Sanitizers Using Infrared Spectroscopy

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Applied Spectroscopy Practica

Applied Spectroscopy Practica 2023年第2期1卷

作者： Aminur Rashid Chowdhury Umar Burney David King Tse-Ang Lee Dan Hutter Tanya Hutter Department of Mechanical Engineering The University of Texas at Austin Austin Texas USAMaterials Science and Engineering Program and Texas Materials Institute The University of Texas at Austin Austin Texas USA Department of Mechanical Engineering The University of Texas at Austin Austin Texas USA Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas USA

Recent fatalities due to methanol and 1-propanol toxicity in alcohol-based hand sanitizers has led the U.S. Food and Drug Administration (FDA) to ban 594 different hand sanitizer brands. The FDA also introduced methanol testing in alcohol-based hand sanitizers before allowing the products to enter the United States This requirement creates a need for inexpensive, rapid, and portable testing methods to measure methanol and 1-propanol concentrations in alcohol-based hand sanitizers. Here we study the performance of infrared (IR) spectroscopy for measuring methanol and 1-propanol concentrations in an alcohol-based hand sanitizer, and compare the performance of two portable spectrometers, Texas Instruments near-infrared (NIR) spectrometer (TI NIR) and NeoSpectra mid-infrared (MIR) spectrometer. The IR absorbance spectra were measured in transmission mode at different path lengths for 52 different hand sanitizer samples spiked with 0%–1% v/v concentrations of methanol and 1-propanol. A partial least-squares regression analysis shows ability to detect contaminant concentrations with a correlation coefficient of determination (r2) up to 0.99 and root mean square error of prediction as low as 0.34% v/v.

关键词： Hand sanitizers toxins methanol 1-propanol infrared spectroscopy partial least-squares regression PLSR

Analysis Of The Importance Of Systolic Blood Pressure Versus Diastolic Blood Pressure In Diagnosing Hypertension: MRA Study.

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Analysis Of The Importance Of Systolic Blood Pressure Versus...

IEEE International Conference on Image Processing

作者： Heba Kandil Ahmed Soliman Fatma Taher Mohammed Ghazal Mohiuddin Hadi Adel Elmaghraby Ayman El-Baz BioImaging Laboratory Department of Bioengineering University of Louisville KY USA Zayed University Dubai UAE Electrical and Computer Engineering Department Abu Dhabi University UAE Department of Radiology University of Louisville KY USA Department of Computer Science and Engineering University of Louisville KY USA

ISBN: (数字)9781728163956

ISBN: (纸本)9781728163963

Hypertension is one of the severest and most common diseases nowadays. It is considered one of the leading contributors to death worldwide. Specialists tend to diagnose hypertension taking into consideration both systolic and diastolic blood pressure (BP) measurements. However, some clinical hypothesis states that under 50 years of age, diastolic may be slightly more predictive of adverse events, while above that age, systolic may be more predictive. The question is should we give more value to systolic BP or diastolic BP when diagnosing diseases such as hypertension? Three different experiments were conducted in this study using magnetic resonance angiography (MRA) data to investigate this question. In each of these experiments, the following methodology was followed: 1) preprocess MRA data to remove noise, bias, or inhomogeneities, 2) segment the cerebral vasculature for each subject using a CNN-based approach, 3) extract vascular features that represent cerebral alterations that precede and accompany the development of hypertension, and 4) finally build feature vectors and classify data into either normotensives or hypertensives based on the cerebral alterations and the blood pressure measurements. The first experiment was conducted on original data set of 342 subjects. While the second and third experiments enlarged the original data set by generating more synthetic samples to make original data set large enough and balanced. Experimental results showed that systolic blood pressure might be more predictive than diastolic blood pressure in diagnosing hypertension with a classification accuracy of 89.3%.

关键词： Hypertension Feature extraction Blood pressure Support vector machines Neural networks Logistics Cells (biology)

Polarization-Tunable Colorimetric Metasurfaces for All-Optical and Non-Destructive Structural Characterization of Polymeric Nanofibers

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arXiv 2025年

作者： Kirya, Paula Hochberg, Justin D. Kim, Han Sol Haddadin, Zaid Bordy, Samantha Byun, Jiuk Pokorski, Jonathan K. Poulikakos, Lisa V. Department of Mechanical and Aerospace Engineering UC San Diego La Jolla CA United States Aiiso Yufeng Li Family Department of Chemical and Nano Engineering UC San Diego La Jolla CA United States Department of Electrical and Computer Engineering UC San Diego La Jolla CA United States Program in Materials Science and Engineering UC San Diego La Jolla CA United States

Metasurfaces have pioneered significant improvements in sensing technology by tailoring strong optical responses to weak signals. When designed with anisotropic subwavelength geometries, metasurfaces can tune responses to varying polarization states of light. Leveraging this to quantify structural alignment in fibrous materials unveils an alternative to destructive characterization methods. This work introduces metasurface-enhanced polarized light microscopy (Meta-PoL), which employs polarization-tunable, guided-mode-resonant colorimetric metasurfaces to characterize molecular and bulk alignment of poly(Ε-caprolactone) (PCL) nanofibers in a far-field configuration. PCL nanofibers drawn at 0%, 400%, and 900% ratios were interfaced with the studied metasurfaces. Metasurface resonances coinciding with the intrinsic drawn nanofiber resonances – confirmed by Stokes Polarimetry – produced the strongest colorimetric enhancement, resultant from alignment-specific nanofiber reflectivity. The enhancement degree corresponded with molecular and bulk alignments for each draw ratio, as measured through differential scanning calorimetry and scanning electron microscopy, respectively. Thus, Meta-PoL presents an all-optical, non-destructive, and quantitative measurement of nanofiber alignment. Copyright © 2025, The Authors. All rights reserved.

关键词： Differential scanning calorimetry

Multimodal Whole Slide Foundation Model for Pathology

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arXiv 2024年

作者： Ding, Tong Wagner, Sophia J. Song, Andrew H. Chen, Richard J. Lu, Ming Y. Zhang, Andrew Vaidya, Anurag J. Jaume, Guillaume Shaban, Muhammad Kim, Ahrong Williamson, Drew F.K. Chen, Bowen Almagro-Perez, Cristina Doucet, Paul Sahai, Sharifa Chen, Chengkuan Komura, Daisuke Kawabe, Akihiro Ishikawa, Shumpei Gerber, Georg Peng, Tingying Le, Long Phi Mahmood, Faisal Department of Pathology Mass General Brigham Harvard Medical School BostonMA United States Data Science Program Dana-Farber Cancer Institute BostonMA United States Cancer Program Broad Institute of Harvard and MIT CambridgeMA United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA United States Helmholtz Munich German Research Center for Environment and Health Munich Germany School of Computation Information and Technology Technical University of Munich Munich Germany Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States Harvard-MIT Division of Health Sciences and Technology Massachusetts Institute of Technology CambridgeMA United States Department of Pathology Pusan National University Busan Korea Republic of Department of Pathology and Laboratory Medicine Emory University School of Medicine AtlantaGA United States Harvard Data Science Initiative Harvard University CambridgeMA United States Department of Systems Biology Harvard Medical School BostonMA United States Department of Preventive Medicine Graduate School of Medicine The University of Tokyo Tokyo Japan Division of Pathology National Cancer Center Exploratory Oncology Research & Clinical Trial Center Chiba Japan

The field of computational pathology has been transformed with recent advances in foundation models that encode histopathology region-of-interests (ROIs) into versatile and transferable feature representations via self-supervised learning (SSL). However, translating these advancements to address complex clinical challenges at the patient and slide level remains constrained by limited clinical data in disease-specific cohorts, especially for rare clinical conditions. We propose TITAN, a multimodal whole slide foundation model pretrained using 335,645 WSIs via visual self-supervised learning and vision-language alignment with corresponding pathology reports and 423,122 synthetic captions generated from a multimodal generative AI copilot for pathology. Without any finetuning or requiring clinical labels, TITAN can extract general-purpose slide representations and generate pathology reports that generalize to resource-limited clinical scenarios such as rare disease retrieval and cancer prognosis. We evaluate TITAN on diverse clinical tasks and find that TITAN outperforms both ROI and slide foundation models across machine learning settings such as linear probing, few-shot and zero-shot classification, rare cancer retrieval and cross-modal retrieval, and pathology report generation. The model is publicly accessible at https://***/mahmoodlab/TITAN © 2024, CC BY-NC-ND.

关键词： Self-supervised learning