Optical Means Research Articles

Passive high-frequency microrheology of blood.

Indicative of various pathologies, blood properties are under intense scrutiny. The hemorheological characteristics are traditionally gauged by bulk, low-frequency indicators that average out critical information about the complex, multi-scale, and multi-component structure. In particular, one cannot discriminate between the erythrocytes contribution to global rheology and the impact of plasma. Nevertheless, in their fast stochastic movement, before they encounter each other, the erythrocytes probe the subtle viscoelasticity of their protein-rich environment. Thus, if these short time scales can be resolved experimentally, the plasma properties could be determined without having to separate the blood components; the blood is practically testing itself. This microrheological description of blood plasma provides a direct link between the composition of whole blood and its coagulability status. We present a parametric model for the viscoelasticity of plasma, which is probed by the erythrocytes over frequency ranges of kilohertz in a picoliter-sized volume. The model is validated both in vitro, using artificial hemo-systems where the composition is controlled, as well as on whole blood where continuous measurements provide real-time information. We also discuss the possibility of using this passive microrheology as an in vivo assay for clinically relevant situations where the blood clotting condition must be observed and managed continuously for diagnosis or during therapeutic procedures at different stages of hemostatic and thrombotic processes.

Strong coupling of single plasmonic nanoparticles and nanogaps with quantum emitters

In cavity quantum electrodynamics, when the interaction between quantum emitter and cavity mode is strong enough to overcome the mean decay rate of the system, it will enter into a strong coupling regime, thereby forming part-light part-matter polariton states. Strong coupling can serve as a promising platform for room temperature Bose-Einstein condensation, polariton lasing, single photon nonlinearity, quantum information, etc. Localized surface plasmons supported by single metal nanostructures possess extremely small mode volume, which is favorable for realizing strong coupling. Moreover, the nanoscale dimensions of plasmonic structures can facilitate the miniaturization of strong coupling systems. Here, the research progress of strong plasmon-exciton coupling between single metal nanoparticles/nanogaps and quantum emitters is reviewed. The theory background of strong coupling is first introduced, including quantum treatment, classical coupled oscillator model, as well as the analytical expressions for scattering and photoluminescence spectra. Then, strong coupling between different kinds of plasmonic nanostructures and quantum emitters is reviewed. Single metal nanoparticles, nanoparticle dimers, and nanoparticle-on-mirror structures constitute the most typical plasmonic nanostructures. The nanogaps in the latter two systems can highly concentrate electromagnetic field, providing optical nanocavities with smaller mode volume than single nanoparticles. Therefore, the larger coupling strength can be achieved in the nanogap systems, which is conducive to strong coupling at the single-exciton level. In addition, the active tuning of strong coupling based separately on thermal, electrical and optical means are reviewed. The energy and oscillator strength of the excitons in transition metal dichalcogenide (TMDC) monolayers are dependent on temperature. Therefore, the strong coupling can be tuned by heating or cooling the system. The excitons in TMDC monolayers can also be tuned by electrical gating, enabling electrical control of strong coupling. Optically tuning the quantum emitters provides another way to actively control the strong coupling. Overall, the research on active tuning of strong plasmon-exciton coupling is still very limited, and more investigations are needed. Finally, this review is concluded with a short summary and the prospect of this field.

68 - Toothbrushing Duration Effect on Streptococcus Mutans Adherence to FRC

The purpose of this research was to study if there was an effect of toothbrushing duration on the adherence of S. mutans to FRC. The FRC sample (EverX Posterior, GC Corp, Japan) was first prepared using the mold in the shape of a disc with a diameter of 10 mm x 2 mm thickness. A total of 16 samples were prepared. Toothbrushing simulation using soft bristles was carried out on 16 samples prepared. The brushing was done with a simulated brushing tool with a speed of 250 rounds/minute and a weight of 200 grams drained in aquades. The durations selected for the simulation were 20, 40 and 60 min. A control group of 0 min toothbrushing was prepared. Streptococcus mutans were first grown, then cultured in liquid BHI medium, and incubated at 37 C for 24 hours. The turbidity of the bacterial suspension was standardized with McFarland standard of 0.5 which was equal to 1.5×10 CFU/mL. The FRC which was given the toothbrushing intervention was added into the BHI culture medium which contained S. mutans. It was then incubated at 37 C for 2 hours. After 2 hours, the FRC samples were removed, washed with PBS and vortexed for 1 minute. The solution containing the S. mutans was analyzed using ELISA reader at a wavelength of 540 nm. Statistical analysis of Anova and LSD were examined after obtaining the data. The results showed the optical density value mean of 0, 20, 40, and 60 minutes of toothbrushing were 0.04300.0003, 0.04310.0005, 0.04320.0012, and 0.0530.0005. Statical analysis showed that there was a significant effect of toothbrushing duration on the adherence of S. mutans on FRC (p<0.05). LSD result showed there was a significant difference between the 60 minutes group and the others (p<0.05). It can be concluded that the toothbrushing simulation duration up to 60 minutes increased the number of S.mutans adherence to the FRC sample.

Digitized, networked optics production

The increasing demands on the quality of high-precision optical components mean that established manufacturing processes are reaching their technical limits. While individual processes can therefore hardly be improved any more, networking production machines digitally throughout the entire process chain offers high potential for meeting the tight tolerances in the optics industry and increasing the production output.To gain these benefits, first, an infrastructure is needed, containing a flexible and module data structure to satisfy different requirements from the processes. Second, the idea of offering services such as initial data analytics, artificial intelligence (AI) and machine learning (ML) must be integrated. In this paper, we present a digital infrastructure, that contains data from the entire process chain of glass and polymer optics production including simulation, process and measurement data. Services to optimize the production process are integrated and provide an outlook on how AI/ML can be added.

Von Willebrand Factor Multimer Patterns in People Living with Human Immunodeficiency Virus Infection.

Endothelial dysfunction contributes to hypercoagulability in people with HIV (PWH). A surrogate marker of this is elevated von Willebrand factor (VWF) which has been documented in PWH. This study compared VWF multimer patterns in PWH who were anti-retroviral therapy (ART) naive and immune reconstituted on ART. VWF multimer analysis was performed with a semi-quantitative electrophoresis assay on plasma from 79 PWH (39 ART-naive and 40 virally suppressed on ART) and 25 normal control samples. The total optical density mean VWF level was significantly increased in PWH and higher in ART-naive versus ART-exposed, virally suppressed patients (p < 0.0001). No quantitative difference was demonstrated in the multimer distribution pattern between the groups. Our findings suggest that there is no difference in multimer distribution between ART-naive and virally suppressed PWH. Due to a small sample size, confirmation in a larger study is required.

ON THE ISSUE OF IMPROVING THE SPEED OF DECISION-MAKING FOR THE USE OF NEAR-EARTH PROBING OUTER SPACE EQUIPMENT

Introduction: This article proposes a methodology for assessing the efficiency of decision-making for the use of near-Earth space sensing tools based on the software implementation of a simulation model for obtaining measurements on space objects in the middle and far near-Earth space zone by space exploration tools with the use of a software and hardware complex for collecting information. Setting the task: to develop an assessment methodology based on a simulation model for detecting space objects in their orbits by ground-based space observation means, taking into account various options for stochastic construction of space object trajectories and operating conditions, technical condition, geographical location and number of optical observation means. Results: a methodology and a simulation model of a software and hardware complex for collecting information about the space situation has been developed, taking into account various options for building orbits of observed space objects and allowing dynamically developing the simulated space situation, as well as modeling changes in the state of observation tools, taking into account changes in their technical condition, weather conditions, daily cycle and geographical location. Practical significance: the proposed methodology and simulation model allows calculating the optimal number of necessary means of observing outer space and their preferred locations based on an assessment of the effectiveness of their functioning during a dynamic change in the states of their functioning. Discussion: the novelty of the proposed task statement is that the structure of the developed methodology and simulation model allows you to take into account various factors affecting the means of observation and build probabilistic estimates of the effectiveness of their functioning based on a dynamic change in the states of functioning of the means of observation.

ИССЛЕДОВАНИЕ ЭФФЕКТИВНОСТИ РЕГИСТРАЦИИ ЧАСТИЧНЫХ РАЗРЯДОВ ОПТИЧЕСКИМ МЕТОДОМ

The method of partial discharges (PD) diagnostics is used to assess the insulation condition of high-voltage equipment in order to control quality and identify the initial process of its aging. The paper presents methods for measuring PD and describes their main advantages and disadvantages. Particular attention is paid to the optical method of registering PDs. An experimental study was carried out with a cable sample and a glass insulator to measure the PD intensity in defective places and record their optical radiation. Voltage to the tested objects was applied from 0 to 26 kV. To register the PD, an electronic-optical flaw detector FILIN-6 device was used. Also, according to the results of the measurement, amplitude-phase diagrams of the PD were obtained, by which it is possible to determine the degree of the defect. It is determined that the threshold level for the appearance of partial discharges is their power of about 100 mW. In this case, an increase in the discharge power to 160 mW leads to the appearance of a discharge visible to the naked eye. The specified partial discharge pow-ers may be relatively harmless only for equipment for voltage classes from 35 kV. Thus, registration of partial discharges by optical means makes it possible to detect defects at a relatively early stage only for equipment for high operating voltages.

Analysis of ground-based optical means of observing laser beacons on board near-Earth spacecraft

Analysis of ground-based optical means of observing laser beacons on board near-Earth spacecraft

Coaxial double-hole PEDOT: PSS electrodes achieving tunable terahertz zoomable convergence.

The local wavefront modulation technique in the terahertz band is an important basis for the development of terahertz modulation technology. Here, an electrically controlled convergent tunable device based on patterned transparent electrode poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) is realized to locally tune the terahertz wavefront. The device consists of two substrates with circular-hole electrodes and liquid crystal sandwiched between them. The refractive index gradient of liquid crystal in the device can be generated by the coaxial double-hole electrodes, which realize continuous control of significant focusing of the terahertz wave. The test results show that the focal length can be modulated in the range of 3-12 cm with varied external voltage; when it varies from 3 to 8 V, the 1/e2 radius of the spot decreases to 1.3 mm, 0.27 times the initial state, and the spot central intensity magnification increases gradually with the change, up to 3.31 times. The acquisition of the large tunable focal length range of the continuous terahertz zoom device shows that the construction of the gradient refractive index is an important method to regulate the terahertz wavefront by optical means, which greatly promotes the research of terahertz imaging devices.

Biocorrosion on Nanofilms Induces Rapid Bacterial Motions via Iron Dissolution.

Stability and reactivity of solid metal or mineral surfaces in contact with bacteria are critical properties for development of biocorrosion protection and for understanding bacteria–solid environmental interactions. Here, we opted to work with nanosheets of iron nanolayers offering arbitrarily large and stable areas of contact that can be simply monitored by optical means. We focused our study on the sediments’ bacteria, the strain Shewanella oneidensis WT MR-1, that served as models for previous research on electroactivity and iron-reduction effects. Data show that a sudden uniform corrosion appeared after an early electroactive period without specific affinities and that iron dissolution induced rapid bacterial motions. By extending the approach to mutant strains and three bacterial species, we established a correlation between corrosion onset and oxygen-depletion combined with iron reduction and demonstrated bacteria’s extraordinary ability to transform their solid environments.

High-resolution photoacoustic microscopy with deep penetration through learning

Optical-resolution photoacoustic microscopy (OR-PAM) enjoys superior spatial resolution and has received intense attention in recent years. The application, however, has been limited to shallow depths because of strong scattering of light in biological tissues. In this work, we propose to achieve deep-penetrating OR-PAM performance by using deep learning enabled image transformation on blurry living mouse vascular images that were acquired with an acoustic-resolution photoacoustic microscopy (AR-PAM) setup. A generative adversarial network (GAN) was trained in this study and improved the imaging lateral resolution of AR-PAM from 54.0 µm to 5.1 µm, comparable to that of a typical OR-PAM (4.7 µm). The feasibility of the network was evaluated with living mouse ear data, producing superior microvasculature images that outperforms blind deconvolution. The generalization of the network was validated with in vivo mouse brain data. Moreover, it was shown experimentally that the deep-learning method can retain high resolution at tissue depths beyond one optical transport mean free path. Whilst it can be further improved, the proposed method provides new horizons to expand the scope of OR-PAM towards deep-tissue imaging and wide applications in biomedicine.

Functional Infectious Nanoparticle Detector: Finding Viruses by Detecting Their Host Entry Functions Using Organic Bioelectronic Devices.

Emerging viruses will continue to be a threat to human health and wellbeing into the foreseeable future. The COVID-19 pandemic revealed the necessity for rapid viral sensing and inhibitor screening in mitigating viral spread and impact. Here, we present a platform that uses a label-free electronic readout as well as a dual capability of optical (fluorescence) readout to sense the ability of a virus to bind and fuse with a host cell membrane, thereby sensing viral entry. This approach introduces a hitherto unseen level of specificity by distinguishing fusion-competent viruses from fusion-incompetent viruses. The ability to discern between competent and incompetent viruses means that this device could also be used for applications beyond detection, such as screening antiviral compounds for their ability to block virus entry mechanisms. Using optical means, we first demonstrate the ability to recapitulate the entry processes of influenza virus using a biomembrane containing the viral receptor that has been functionalized on a transparent organic bioelectronic device. Next, we detect virus membrane fusion, using the same, label-free devices. Using both reconstituted and native cell membranes as materials to functionalize organic bioelectronic devices, configured as electrodes and transistors, we measure changes in membrane properties when virus fusion is triggered by a pH drop, inducing hemagglutinin to undergo a conformational change that leads to membrane fusion.

Optical Probing of Crystal Lattice Configurations in Single CsPbBr3 Nanoplatelets.

Quantum-confined nanostructures of CsPbBr3 with luminescence quantum efficiencies approaching unity have shown tremendous potential for lighting and quantum light applications. In contrast to CsPbBr3 quantum dots, where the fine structure of the emissive exciton state has been intensely discussed, the relationship among lattice orientation, shape anisotropy, and exciton fine structure in lead halide nanoplatelets has not yet been established. In this work, we investigate the fine structure of the bright triplet exciton of individual CsPbBr3 nanoplatelets by polarization-resolved micro- and magnetophotoluminescence spectroscopy at liquid helium temperature and find a large zero-field splitting of up to 2.5 meV. A unique relation between the crystal structure and the photoluminescence emission confirms the existence of two distinct crystal configurations in such nanoplatelets with different alignments of the crystal axes with respect to the nanoplatelet facets. Polarization-resolved experiments eventually allow us to determine the absolute orientation of an individual nanoplatelet on the substrate purely by optical means.

Could Macroscopic Dark Matter (Macros) Give Rise to Mini-Lightning Flashes out of a Blue Sky without Clouds?

A recent study pointed out that macroscopic dark matter (macros) traversing through the Earth’s atmosphere can give rise to hot and ionized channels similar to those associated with lightning leaders. The authors of the study investigated the possibility that when such channels created by macros pass through a thundercloud, lightning leaders may be locked in by these ionized channels, creating lightning discharges with perfectly straight channels. They suggested the possibility of detecting such channels as a means of detecting the passage of macros through the atmosphere. In this paper, we show that such macros crossing the atmosphere under fair weather conditions could also give rise to mini-lightning flashes with current amplitudes in the order of a few hundred Amperes. These mini-lightning flashes would generate a thunder signature similar to or stronger than those of long laboratory sparks and they could also be detected by optical means. As in the case of thunderstorm-assisted macro lightning, these mini-lightning flashes are also associated with straight channels. Moreover, since the frequency of mini-lightning flashes is about thirty times greater than the macro-generated lightning flashes assisted by thunderstorms, they could be used as a means to look for the paths of macroscopic dark matter crossing the atmosphere.

Optical information processing: A historical overview

Optical information processing lies at the intersection of optics and signal processing. It involves the processing of optical information as well as the use of optical means to process information, the later being the main emphasis of this work. A historical review of various forms of optical signal processing and holography, optoelectronic and digital optical computing, and optical interconnections is given.

Magneto-chiral anisotropy: From fundamentals to perspectives.

The interplay between chirality and magnetic fields gives rise to a cross effect referred to as magneto-chiral anisotropy (MChA), which can manifest itself in different physical properties of chiral magnetized materials. The first experimental demonstration of MChA was by optical means with visible light. Further optical manifestations of MChA have been evidenced across most of the electromagnetic spectrum, from terahertz to X-rays. Moreover, exploiting the versatility of molecular chemistry toward chiral magnetic systems, many efforts have been made to identify the microscopic origins of optical MChA, necessary to advance the effect toward technological applications. In parallel, the replacement of light by electric current has allowed the observation of nonreciprocal electrical charge transport in both molecular and inorganic conductors as a result of electrical MChA (eMChA). MChA in other domains such as sound propagation, photochemistry, and electrochemistry are still in their infancy, with only a few experimental demonstrations, and offer wide perspectives for further studies with potentially large impact, like the understanding of the homochirality of life. After a general introduction to MChA, we give a complete review of all these phenomena, particularly during the last decade.

ILUZORYCZNA RESTYTUCJA NIEZACHOWANYCH OBIEKTÓW ARCHITEKTONICZNYCH – ANALIZA METOD I STUDIUM PRZYPADKU

The article concerns the illusory presentation of non-existent architectural objects directly in the place of their original location. This specific conservation method is considered as a tool for disseminating knowledge about the original architectural landscape of places where it has undergone transformations. The authors believe that its implementation may contribute to the growth of the identity of cities and their inhabitants. The concept refers to augmented reality, but the authors use only optical means to create a virtual component, The article presents the results of theoretical analysis and practical experiments, pointing to the advantages and disadvantages of the method.

Dynamic behavior and mechanism analysis of tip wetting process under flash boiling conditions

The increasingly stringent emission regulations have required that the State-of-the-art internal combustion engines operated with minimum particulate matters produced. Flash boiling spray is considered to be potential technology for achieving high efficiency combustion, with its benefit of improving fuel-air mixing process in cylinders and eliminating spray-wall impingement. On the other side, it is believed that flash boiling would also enhance the injector tip wetting phenomenon since the widened spray plume would interact with the pre-hole more frequently, causing tip sooting and deposits. However, understanding of the physics related to the tip wetting film formation, propagation and evaporation is still lacking in the existing literature. This investigation focused on a two-hole gasoline direct injection (GDI) fuel injector, and its tip wetting characteristics were analyzed with optical means. High-speed imaging was used to illustrate the film dymanics in the near field, and laser-induced fluorescence was used to capture clear footprints of the tip film. Various boundary conditions, such as the fuel temperature, ambient pressure, and injection durations were investigated to figure out their impacts on the tip wetting process. It was found that the tip wetting process could be divided into two stages, namely wide plume induced wetting and dribble induced wetting, among which the fuel dribble was the primary cause of tip wetting. Besides, the impact of flash boiling spray on tip wetting could be analyze in two aspects. The enhanced wide plume effect and finner dribble would significantly increase the fuel deposited onto the tip, while the strong evaporating nature can help eliminate negative tip wetting effects from flash boiling atomization.

Acoustically Driven Stark Effect in Transition Metal Dichalcogenide Monolayers.

The Stark effect is one of the most efficient mechanisms to manipulate many-body states in nanostructured systems. In mono- and few-layer transition metal dichalcogenides, it has been successfully induced by optical and electric field means. Here, we tune the optical emission energies and dissociate excitonic states in MoSe2 monolayers employing the 220 MHz in-plane piezoelectric field carried by surface acoustic waves. We transfer the monolayers to high dielectric constant piezoelectric substrates, where the neutral exciton binding energy is reduced, allowing us to efficiently quench (above 90%) and red-shift the excitonic optical emissions. A model for the acoustically induced Stark effect yields neutral exciton and trion in-plane polarizabilities of 530 and 630 × 10-5 meV/(kV/cm)2, respectively, which are considerably larger than those reported for monolayers encapsulated in hexagonal boron nitride. Large in-plane polarizabilities are an attractive ingredient to manipulate and modulate multiexciton interactions in two-dimensional semiconductor nanostructures for optoelectronic applications.

Deep forest: Neural network reconstruction of the Lyman-α forest

ABSTRACT We explore the use of Deep Learning to infer physical quantities from the observable transmitted flux in the Ly α forest. We train a Neural Network using redshift z = 3 outputs from cosmological hydrodynamic simulations and mock data sets constructed from them. We evaluate how well the trained network is able to reconstruct the optical depth for Ly α forest absorption from noisy and often saturated transmitted flux data. The Neural Network outperforms an alternative reconstruction method involving log inversion and spline interpolation by approximately a factor of 2 in the optical depth root mean square error. We find no significant dependence in the improvement on input data signal to noise, although the gain is greatest in high optical depth regions. The Ly α forest optical depth studied here serves as a simple, one dimensional, example but the use of Deep Learning and simulations to approach the inverse problem in cosmology could be extended to other physical quantities and higher dimensional data.