Irina A. Okkelman, Hang Zhou, Sergey M. Borisov
et al.
Abstract Increased micro- and nanoplastic (MNP) pollution poses significant health risks, yet the mechanisms of their accumulation and effects on absorptive tissues remain poorly understood. Addressing this knowledge gap requires tractable models coupled to dynamic live cell imaging methods, enabling multi-parameter single cell analysis. We report a new method combining adult stem cell-derived small intestinal organoid cultures with live fluorescence lifetime imaging microscopy (FLIM) to study MNP interactions with gut epithelium. To facilitate this, we optimized live imaging of porcine and mouse small intestinal organoids with an ‘apical-out’ topology. Subsequently, we produced a set of pristine MNPs based on PMMA and PS (<200 nm, doped with deep-red fluorescent dye) and evaluated their interaction with organoids displaying controlled epithelial polarity. We found that nanoparticles interacted differently with apical and basal membranes of the organoids and showed a species-specific pattern of cellular uptake. Using a phasor analysis approach, we demonstrate improved sensitivity of FLIM over conventional intensity-based microscopy. The resulting ‘fluorescence lifetime barcoding’ enabled distinguishing of different types of MNP and their interaction sites within organoids. Finally, we studied short (1 day)- and long (3 day)-term exposure effects of PMMA and PS-based MNPs on mitochondrial function, total cell energy budget and epithelial inflammation. We found that even pristine MNPs could disrupt chemokine production and mitochondrial membrane potential in intestinal epithelial cells. The presented FLIM approach will advance the study of MNP toxicity, their biological impacts on gastrointestinal tissue and enable the tracing of other fluorescent nanoparticles in live organoid and 3D ex vivo systems.
Christopher L. McCleese, Michael C. Brennan, Nathan Episcopo
et al.
Proper derivation of CH3NH3PbX3 (MAPbX3; where X = Cl−, Br−, I−) optical constants is a critical step toward the development of high‐performance perovskite devices. To date, the optical dispersions at all wavelengths have been inconsistently characterized by under‐approximating or omitting anomalous spectral features. Herein, a rigorous optical dispersion data analysis of single‐crystal MAPbBr3 involving variable‐angle spectroscopic ellipsometry data appended with transmission intensity data is presented. This approach yields a more robust derivation of the refractive index and extinction coefficient for both anomalous (absorptance) and normal (no absorptance) optical dispersion regimes. Using the derived optical constants, illustrative modeled perovskite solar cell device designs are presented in relation to nonrealistic designs prepared using representative optical constants reported in the literature. In comparison, the derived optical constants enables the modeling of layer thicknesses to maximize absorption by the active layer (MAPbBr3) and minimize parasitic optical absorptance by the nonactive layers at broad angles of incidence (≈0°–70°). This robust derivation of MAPbBr3 optical constants is expected to impact the optical dispersion data analysis of all perovskite analogs and expedite targeted development of, for example, solar cell, light‐emitting diode, photo‐ and X‐ray/γ‐ray detector, and laser system technologies.
Abstract Miniaturizing spectrometers for compact and cost-effective mobile platforms is a major challenge in current spectroscopy research, where conventional spectrometers are impractical due to their bulky footprint. Existing miniaturized designs primarily rely on precalibrated response functions of nanophotonic structures to encode spectral information captured in a snapshot by detector arrays. Accurate spectrum reconstruction is achieved through computational techniques, but this requires precise component design, high-precision fabrication, and calibration. We propose an ultra-simplified computational spectrometer that employs a one-to-broadband diffraction decomposition strategy facilitated by a numerical regularized transform that depends only on the spectrum of the diffracted radiation. The key feature of our design is the use of a simple, arbitrarily shaped pinhole as the partial disperser, eliminating the need for complex encoding designs and full spectrum calibration. Our spectrometer achieves a reconstructed spectral peak location accuracy of better than 1 nm over a 200 nm bandwidth and excellent resolution for peaks separated by 3 nm in a bimodal spectrum, all within a compact footprint of under half an inch. Notably, our approach also reveals a breakthrough in broadband coherent diffractive imaging without requiring any prior knowledge of the broadband illumination spectrum, assumptions of non-dispersive specimens, or correction for detector quantum efficiency.
In this study, we demonstrate a high-power ytterbium-doped fiber laser (YDFL) based on laser diodes (LDs) directly pumping scheme. Tandem pumping and LD direct pumping are two common schemes for generating high-brightness laser output in YDFL. Compared to tandem pumping, LD direct pumping scheme has prominent advantages such as high efficiency, small size, and low cost. Therefore, it has a significant competitive advantage in industrial applications. We report a 20.27 kW monolithic fiber amplifier with directly dual-wavelength LDs counter pumping. The fiber amplifier emitting at 1080 nm has an optical-to-optical efficiency of 84.8%. The Raman intensity is more than 50 dB lower than the signal light intensity. By optimizing the design of YDF and components, the output power and beam quality of the laser can be further enhanced.
Vehicular quantum communication terminals (VQCTs) are crucial for establishing global-scale quantum networks. High-precision line-of-sight (LOS) pointing is essential for fast and reliable acquisition in satellite-based quantum key distribution (QKD). The pointing accuracy of VQCTs is affected by attitude measurement errors, mechanical structure errors, and structural instability errors resulting from platform movement. By mounting attitude sensors on the LOS of VQCTs, we directly measure the LOS attitude. This completely eliminates the impact of mechanical structure errors and structural instability errors on pointing accuracy. Furthermore, we propose a line-of-pointing calibration method and a pointing model for VQCTs based on LOS attitude measurement. The pointing accuracy of this model is primarily reliant on the accuracy of attitude sensors. Two experiments were conducted to validate the effectiveness of our model. One is the star pointing experiment, comparing with the existing pointing model for VQCTs, our model significantly reduces the pointing errors by 93%, from 1296″ to 87.8″. This substantiates that our model eliminates mechanical structure errors and structural instability errors. Another is the successful acquisition of a quantum communication satellite, which demonstrates the feasibility of the proposed model for implementing the satellite-to-motion platform QKD and global-scale quantum networks.
Abstract Narrowband red, green, blue self-filtering perovskite photodetectors and a broadband white photodetector are incorporated into a single pixel imaging camera to mimic the long-, medium-, and short-wavelength cone cells and rod cells in human visual system, leading to the demonstration of high-resolution color images in diffuse mode.
The laureates of the 2023 Nobel Prize in Physics are three researchers: Pierre Agostini (The Ohio State University, USA), Ferenc Krausz (Max Planck Institute of Quantum Optics, Garching and Ludwig-Maximilians-Universität München, Germany), and Anne L'Huillier (Lund University, Sweden). The prize was awarded for developing experimental methods that allow the generation of extremely short (attosecond) laser light pulses to study the dynamics of electrons in matter. The paper presents information about the scientific achievements of this year's Nobel laureates, which "give humanity new tools for exploring the world of electrons inside atoms and molecules." The paper describes the fundamental physical experiments that launched the new scientific field of attosecond physics. With its development, world science has gained many opportunities to study various fundamental physical processes and phenomena, as well as to create cutting-edge technologies, a brief overview of which is provided in the paper. A description of the new physical phenomenon discovered by the laureates, which was called electron-ion recollision, is given.
An as yet outstanding goal in quantum optics is the realization of fast optical nonlinearities at the single-photon level. This would allow for the implementation of optical devices with new functionalities such as single-photon switches/transistors1,2 or controlled-phase gates3. Although nonlinear optics effects at the single-emitter level have been demonstrated in a number of systems4,5,6,7,8,9,10,11,12,13, none of these experiments showed single-photon switching on ultrafast timescales. Here, we perform pulsed two-colour spectroscopy and demonstrate that, in a strongly coupled quantum dot–cavity system, the presence of a single photon on one of the fundamental polariton transitions can turn on light scattering on a transition from the first to the second Jaynes–Cummings manifold. The overall switching time of this single-photon all-optical switch14 is ∼50 ps. In addition, we use the single-photon nonlinearity to implement a pulse correlator. Our quantum dot–cavity system could form the building block of future high-bandwidth photonic networks operating in the quantum regime15,16,17,18. Researchers report the first demonstration of an ultrafast all-optical switch in the single-photon regime. The device, which consists of an InAs/GaAs quantum dot in a photonic crystal defect cavity, exhibits a coherent coupling constant of 141 meV and a quality factor of 25,000. The overall switching time is around 50 ps.
Xiuting Li, Mohesh Moothanchery, Cheng Yi Kwa
et al.
Atopic dermatitis (AD) is a chronic and pruritic skin inflammatory disease causing a significant burden to health care management and patient’s quality of life. Seemingly healthy skin or non-lesional sites on AD patients still presents skin barrier defects and immune response, which can develop to AD at a later stage. To investigate further the balance between the epidermal barrier impairment and intrinsic immune dysregulation in AD, we exploited multispectral Raster-Scanning Optoacoustic Mesoscopy (ms-RSOM) to image lesional and non-lesional skin areas on AD patients of different severities non-invasively to elucidate their structural features and functional information. Herein, we demonstrate the objective assessment of AD severity using relative changes in oxygen saturation (δsO2) levels in microvasculature along with other structural parameters such as relative changes in epidermis thickness (δET) and total blood volume (δTBV) between the lesional and non-lesional areas of the skin. We could observe an increasing trend for δsO2 and δTBV, which correlated well with the subjective clinical Scoring Atopic Dermatitis (SCORAD) for evaluating the severity. Notably, δET showed a decreasing trend with AD severity, indicating that the difference in epidermal thickness between lesional and non-lesional area of the skin decreases with AD severity. Our results also correlated well with conventional metrics such as trans-epidermal water loss (TEWL) and erythrosine sedimentation rate (ESR). We quantified the δsO2 and δET changes to objectively evaluate the treatment response before and four months after treatment using topical steroids and cyclosporine in one severe AD patient. We observed reduced δsO2 and δET post treatment. We envision that in future, functional and structural imaging metrics derived from ms-RSOM can be translated as objective markers to assess and stratify the severity of AD and understand the function of skin barrier dysfunctions and immune dysregulation. It could also be employed to monitor the treatment response of AD in regular clinical settings.
An approach for wideband phase noise measurement of microwave signal sources is proposed based on all-optical microwave signal processing. In the proposed scheme, an optical carrier is sequentially modulated by the signal under test (SUT) in a phase modulator and a dual-polarization modulator to generate two +1st-order sidebands with orthogonal polarizations. A time delay is introduced between two sidebands by a span of low-loss optical fiber. Combined with a polarization controller and a polarizer, photonic microwave downconversion with a desired phase shift and time delay can be realized after photodetection, and the phase noise of the SUT can be calculated thereafter. Since all the microwave signal processing functions in the conventional photonic-delay-line-based phase noise measurement system are implemented in the optical domain, the proposed scheme has a large operational bandwidth and a high measurement sensitivity. In the experimental demonstration, accurate phase noise measurement of SUTs is achieved in a frequency range of 10-35 GHz, and a phase noise floor as low as −132.16 dBc/Hz at 10 kHz is obtained.
We propose and experimentally demonstrate a photonic-assist measurement of microwave frequency by utilizing two cascaded photonic crystal (PC) cavities. By injecting different powers into the PC cavities, the device transmission spectra could be effectively manipulated. Consequently, the central frequencies of the microwave photonic filters (MPFs) can be flexibly adjusted. By utilizing the different MPF responses, adjustable amplitude comparison functions (ACFs) could be constructed. As the mapping relationships between the ACF ratios and the microwave frequencies are unique, the frequency with dynamic ranges could be measured according to the adjustable ACFs. The experimental results show that the measurement range of the microwave frequency is from 9 GHz to 19 GHz and the largest measurement errors are lower than 0.15 GHz. More importantly, the required optical power to manipulate the nanocavities is highly energy-efficient for on-chip nonlinear effect-based microwave measurements. The energy-efficient silicon device with compact size and low power is significant for dynamic frequency measurements in on-chip microwave systems.
The fringe projection technique has been widely used in optical measurements. In this paper, we demonstrate a scheme to measure the 3D displacement of a deformed sample using Talbot fringe projection. In this process, we designed a two-dimensional square Talbot hologram. In this approach, we used the basic principle of triangulation, and a computer-controlled liquid crystal spatial light modulator (LC-SLM) was placed in the optical path. The Talbot array hologram was displayed on the LC-SLM screen and projected onto the surface of a sample. Two patterns were recorded: one before and one after deformation. We simultaneously acquired the in-plane and out-of-plane displacements using the digital image correlation (DIC) method. This scheme is simple and easily implemented. Theoretical and experimental results are presented.
Wahyu Hendra Gunawan, Yang Liu, Chien-Hung Yeh
et al.
We propose and experimentally demonstrate a color-shift-keying embedded direct-current-optical-orthogonal-frequency-division-multiplexing (CSK-DCO-OFDM) scheme for the VLC systems. The proposed scheme can provide not only non-flickering aggregated optical power to reduce human health concerns, but also offers additional modulation dimension or flexibility to the CSK by including high data rate OFDM signal. The data rate is increased from 10 Mbit/s in the original CSK signal to 70.43 Mbit/s in the CSK-DCO-OFDM signal, and both the CSK and OFDM signals satisfy the forward-error-correction (FEC) threshold.
Surface plasmon polaritons with noble metals lack the capability to restrain an optical field in the long wavelength region, while surface phonon polaritons with polar dielectric crystals have been regarded as a potential low-loss alternative. In this paper, long range surface phonon resonance (LRSPhR) is designed to operate in the mid-infrared (MIR) wavelength regime with a narrow resonance dip. Furthermore, by coupling a photonic waveguide with the LRSPhR, strong coupling between waveguide mode and long-range surface phonon polariton has been realized to form high Q Fano resonance. By employing such structure as the index sensor, it is shown that the bulk sensitivity and surface sensitivity can reach ∼9000 and 266.9 RIU<sup>–1</sup>, respectively, which shows a great enhancement comparing with the one based on merely LRSPhR. The proposed configuration can be a promising platform for MIR biochemical sensing.
Vadim Elagin, Anton Smirnov, Vladimir Yusupov
et al.
The bactericidal effect of laser radiation with a quartz fiber-based transmission system with a strong absorption coating converter against bacteria associated with urological stones has been studied. Gram-negative rod Escherichia coli and the Gram-positive coccus Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium were used in this study. Each bacterial species was treated by continuous-wave near infrared laser coupled with bare fiber tip or strongly absorption coating fiber tip. After treatment, the temperature of bacterial suspension was measured. In addition, the temperature distribution was analyzed. It has been shown that using laser with a strongly absorption coating fiber tip results in significant bactericidal effect. The decrease of the amount of E. coli and S. epidermidis was 100% after treatment with an output power of 6W of radiation at a wavelength of 0.97μm for 40s. Number of S. aureus and Ent. faecium colony-forming unit was reduced to 70% after same exposure. The peak temperature of bacterial suspension was 86∘C after treatment by laser with a strongly absorption coating fiber tip. Laser with a strongly absorption coating fiber tip provides large-scale hydrodynamic flows directed away from the fiber tip. The laser with a strongly absorption coating fiber tip has bactericidal effect. The main role is associated with the effect of high temperature, which, in the form of flow in a liquid medium, affects bacteria.
The properties of light wave propagation with stochastic scattering in a fiber are particularly attractive because of their influence in various applications. Although stochastic scattering in fibers is of great significance, until now, no accurate theoretical model has described the randomness of the distributions and variations in scattering since the scattering sources are regarded as centralized or homogeneously distributed. In this paper, we proposed a model to analyze the random variation in scattering with time and location. Then, we employed the model to simulate stochastic scattering in distributed fiber Raman amplification (FRA) systems, including Rayleigh backscattering and spontaneous Raman scattering, which are crucial limitations of the distributed FRA systems. The simulations agreed well with our experimental measurements, proving that our model efficiently described stochastic scattering spectra and distributions in FRAs. Our theory accurately analyzed the distribution and evolution of scattering along the fiber and is a promising tool for optimizing the performance of distributed fiber systems, especially systems with distributed amplification such as fiber communication systems, random feedback fiber lasers, and fiber sensors.
Purpose: Near visual acuity is an essential measurement during an oculo-visual assessment. Short duration continuous text reading charts measure reading acuity and other aspects of reading performance. There is no standardized version of such chart in Arabic. The aim of this study is to create sentences of equal readability to use in the development of a standardized Arabic continuous text reading chart.
Methods: Initially, 109 Arabic pairs of sentences were created for use in constructing a chart with similar layout to the Colenbrander chart. They were created to have the same grade level of difficulty and physical length. Fifty-three adults and sixteen children were recruited to validate the sentences. Reading speed in correct words per minute (CWPM) and standard length words per minute (SLWPM) was measured and errors were counted. Criteria based on reading speed and errors made in each sentence pair were used to exclude sentence pairs with more outlying characteristics, and to select the final group of sentence pairs.
Results: Forty-five sentence pairs were selected according to the elimination criteria. For adults, the average reading speed for the final sentences was 166 CWPM and 187 SLWPM and the average number of errors per sentence pair was 0.21. Childrens’ average reading speed for the final group of sentences was 61 CWPM and 72 SLWPM. Their average error rate was 1.71.
Conclusions: The reliability analysis showed that the final 45 sentence pairs are highly comparable. They will be used in constructing an Arabic short duration continuous text reading chart.