Light Channel Research Articles

Three-channel-switchable coded aperture snapshot multispectral polarization imaging.

An ingenious and compact snapshot multispectral polarization imaging method is proposed based on a new, to the best of our knowledge, three-channel-switchable spectral polarization coded aperture. We utilize the coded aperture to simultaneously select three-channel light components and encode them with specific spectrum-polarization coefficients. It enables easy retrieval of each channel's light component from the mixed information via polarization measurements and linear decoding operations. Distinct three-channel light components can be detected simultaneously, thus achieving either three spectral images or linearly polarized ones per snapshot. The number of detectable light components is unlimited and triple that of snapshot times, showing its superior capability in measuring spectral polarization properties. The resulting prototype is miniaturized, featuring compact dimensions of Φ5.5 cm × 25 cm and a light weight of ∼800 g. This is attributed to its simplistic structure comprising a monochrome polarization detector and an imaging lens integrated with the coded aperture, making it suitable for portable and on-board applications. Furthermore, the absence of advanced or costly production technologies for manufacturing the prototype ensures an affordable price for its acquisition, facilitating widespread adoption and application of the proposed method.

Flaw detection of railway catenary insulator based on DP-YOLOv5 algorithm with bright and dark channel enhancement

Abstract To ensure the timely detection of safety hazards in overhead transmission lines with railroad conductors and improve the accuracy of night insulator defect detection, this paper proposes the DP-YOLOv5 algorithm with dark and light channel enhancement optimization. It improves the night insulator image quality by introducing the dark and light channel enhancement algorithm, builds a lightweight network by combining the DP-BS module, and adds the Shuffle Attention module to enhance the feature extraction and ensure detection accuracy. At the same time, the EC-Loss loss function is used to optimize the prediction frame adjustment, accelerate the model convergence, and improve detection efficiency and accuracy. The simulation results show that the insulator dataset processed by DP-YOLOv5 has an accuracy of 95.3%, a recall of 94.8%, an average accuracy of 95.5%, and FLOPs of 219.3. Compared with YOLOv5, the mapped value is improved by 0.9%, the F1 is improved by 1%, and the model parameter and FLOPs are reduced by 48.8% and 50.8%, respectively.

Simultaneous mesoscopic measurement and manipulation of mouse cortical activity.

Dynamics of activity across the cerebral cortex at the mesoscopic scale - coordinated fluctuations of local populations of neurons - are essential to perception and cognition and relevant to computations like sensorimotor integration and goal-directed task engagement. However, understanding direct causal links between population dynamics and behavior requires the ability to manipulate mesoscale activity and observe the effect of manipulation across multiple brain regions simultaneously. Here, we develop a novel system enabling simultaneous recording and manipulation of activity across the dorsal cortex of awake mice, compatible with large-scale electrophysiology from any region across the brain. Transgenic mice expressing the GCaMP calcium sensor are injected systemically with an adeno-associated virus driving expression of the ChrimsonR excitatory opsin. This strategy drives expression of the blue-excited calcium indicator, GCaMP, in excitatory neurons and red-excited Chrimson opsin in inhibitory neurons. We demonstrate widefield single-photon calcium imaging and simultaneous galvo-targeted laser stimulation over the entire dorsal cortical surface. The light channels of the imaging and the opsin do not interfere. We characterize the spatial and temporal resolution of the method, which is suitable for targeting specific cortical regions and specific time windows in behavioral tasks. The preparation is stable over many months and thus well-suited for long-term behavioral experiments. This technique allows for studying the effect of cortical perturbations on cortex-wide activity, on subcortical spiking activity, and on behavior, and for designing systems to control cortical activity in closed-loop.

Three-dimensional endoscopic imaging system based on micro-lithography mask structured light projection

To achieve effective in-situ endoscopic diagnosis and treatment, the measurement of the size of lesions (such as tumors) and the characterization of their shape are important. However, the application of binocular endoscopy is still limited due to issues such as the lack of texture in some scenes, difficulty in matching, and large computational load. To address this, we have developed a 3D endoscopic imaging system based on micro-lithography mask structured light projection to measure the shape and size of targets within the endoscopic view. Firstly, a brand new mechanical design was implemented for the endoscope tip to integrate both white light and structured light channels. Then, a projection lens based on Q-type aspheric design and a micro-lithography mask based on the M-array were designed to achieve high contrast and high-resolution structured light projection in the endoscopic scene. Finally, by identifying feature points in the target and reference images, pixel matching and disparity calculation were achieved, allowing for 3D reconstruction. Our proposed 3D endoscopic imaging system was validated in a gastric model and a cervical model, where the model was reconstructed and compared with the ground truth, yielding mean RMSE of 0.20–0.31 mm at a working distance of about 40 mm, thus confirming the effectiveness of our system.

PMMA light channels facilitate the additive manufacturing of complex-structured SiC reflector mirrors

The rapid manufacturing of lightweight SiC reflector mirrors has always posed a formidable challenge. We have successfully solved the problem of SiC slurry’s difficulty in vat photopolymerization by using highly transparent organic particles to construct the light channels for the first time. Through the integration of digital light processing with reaction sintering, we manufactured complex-structured SiC/Si reflector mirrors. Utilizing the light channels constructed with PMMA, ultraviolet light can effectively penetrate SiC slurry, thereby significantly enhancing the curing depth. During subsequent reaction sintering, PMMA particles induce the formation of numerous spherical silicon through dissolution-precipitation mechanism, alleviating stress concentration in the matrix and enhancing the flexural strength of SiC/Si ceramics. The method achieves significantly higher curing depth for SiC slurry and greater flexural strength for ceramic compared to similar materials. Extending the success above further, we have demonstrated their potential as high-quality products for practical applications.

Research on visible light communication channel model in underground mines

Abstract In order to effectively model the Visible Light Communication (VLC) channel in underground mines, this paper delves into the challenges of the underground environment and develops a mathematical model by analyzing the propagation characteristics of visible light. The objective is to deepen our understanding of light signal behavior in this unique setting. Most existing research focuses on visible light channel modeling in indoor environments, with limited studies on underground mines. Our model takes into account the irregular surfaces of mine walls, as well as the effects of factors such as high dust concentration, extreme temperatures and pressures, light absorption by mine walls, and obstruction caused by large machinery on the propagation of visible light signals. This paper introduces refined optical propagation models that incorporate both scattering and light absorption considerations, resulting in a maximum received power of -46.12 dBm, which is significantly lower than that in indoor environments. These models enhance our ability to analyze and improve channel performance, thereby optimizing communication efficiency.

Stream Theory

Purpose: The main objective of this research was trying to solve the misunderstood nature of light by introducing and studying fluid optic and its influence on physical science. Methodology: The research adopted observation and a study of already published online and school library books on optics and physical science. Observation is always the best approach to quote a natural occurrence and behavior, the researcher observed the behaviour of thin light by isolating themself for a long time in a dark room having roof holes. Findings: The research findings revealed that; light is not basically a wave, a particle or a photon. Light is sensibly a fluid. Fluid optics has no assumptions and weaknesses as other earlier optical theories as fluid optics clearly brings the channels of light (The streams) and its close link, agreement and influence on physical science as physical nature is brought into focus. Unique contribution to Theory, Practice and Policy: Stream theory completely solves the mystery of light and brings proper understanding of optics now fluid optics. Adoption of the theory and its concepts completely exposes physical science into focus with ease in understanding the natural phenomenon related to optics as the theory avoids assumptions and connects geometrical optics and physical optics to one singular optical study (fluid optics) as a step to singularity achievement in physics. (It is that and it happened that way).

Design of a multi-carrier X-ray source for communication with energy modulation information.

X-ray communication is a kind of space communication technology which uses X-ray as information carrier. In order to improve the information transmission capacity, communication rate and anti-interference ability of X-ray communication, we proposes to design a novel multi-target X-ray source. The source is composed of a fast switching module of light channels based on FPGA technology and four photoelectric X-ray tubes with different target materials: Cr, Fe, Ni, and Cu. Using Geant4 software, we determined the optimal target thickness for each material, which enabled us to fully leverage the characteristic X-rays for multi-channel signal modulation transmission. Moreover, using CST software for particle trajectory simulation and optimization of the electron beam revealed that at a tube voltage of 20 kV, the focus area measures approximately 1.2 mm×1.2 mm. The simulations show that four kinds of spectra with high distinctiveness can be generated from the Cr, Fe, Ni, and Cu targets. Within a single modulation period, these spectra can be combined in various ways to create 16 different X-ray spectra signals, thereby increasing the number of communication elements and enhancing the information transmission rate.

Multi-sensor integration on one microfluidics chip for single-stranded DNA detection

PurposeThis study aims to improve detection efficiency of fluorescence biosensor or a graphene field-effect transistor biosensor. Graphene field-effect transistor biosensing and fluorescent biosensing were integrated and combined with magnetic nanoparticles to construct a multi-sensor integrated microfluidic biochip for detecting single-stranded DNA. Multi-sensor integrated biochip demonstrated higher detection reliability for a single target and could simultaneously detect different targets.Design/methodology/approachIn this study, the authors integrated graphene field-effect transistor biosensing and fluorescent biosensing, combined with magnetic nanoparticles, to fabricate a multi-sensor integrated microfluidic biochip for the detection of single-stranded deoxyribonucleic acid (DNA). Graphene films synthesized through chemical vapor deposition were transferred onto a glass substrate featuring two indium tin oxide electrodes, thus establishing conductive channels for the graphene field-effect transistor. Using π-π stacking, 1-pyrenebutanoic acid succinimidyl ester was immobilized onto the graphene film to serve as a medium for anchoring the probe aptamer. The fluorophore-labeled target DNA subsequently underwent hybridization with the probe aptamer, thereby forming a fluorescence detection channel.FindingsThis paper presents a novel approach using three channels of light, electricity and magnetism for the detection of single-stranded DNA, accompanied by the design of a microfluidic detection platform integrating biosensor chips. Remarkably, the detection limit achieved is 10 pm, with an impressively low relative standard deviation of 1.007%.Originality/valueBy detecting target DNA, the photo-electro-magnetic multi-sensor graphene field-effect transistor biosensor not only enhances the reliability and efficiency of detection but also exhibits additional advantages such as compact size, affordability, portability and straightforward automation. Real-time display of detection outcomes on the host facilitates a deeper comprehension of biochemical reaction dynamics. Moreover, besides detecting the same target, the sensor can also identify diverse targets, primarily leveraging the penetrative and noninvasive nature of light.

A visible light positioning system for coal mine personnel based on convolutional recurrent neural network

Visible Light Positioning (VLP) technology exhibits promising potential for underground coal mine positioning. While numerous studies have explored VLP in indoor environments, attention to VLP systems for underground mines still needs to be improved. In this paper, based on the traditional indoor visible light communication channel model, the effects of unique features on VLP, such as irregular walls, inclined and rotating receiving ends, and coal dust particles in underground mines, are considered and modeled in detail. In order to improve the accuracy and reliability of personnel VLP in complex mine environments, this paper proposes a deep-learning-based VLP system for underground personnel in coal mines, which consists of two LEDs and four photodetectors (PDs), where the four PDs are mounted on miners' helmets, in conjunction with the actual mine environment. Due to environmental factors and noise, there are apparent spatio-temporal characteristics in the received signal strength of the PDs. Therefore, the system adopts a convolutional recurrent neural network (CRNN) for feature extraction. In the experimental phase, the method's average localization error was 11.24 cm, with 90% of the localization errors within 20.4 cm. The experimental results show that the system has high positioning accuracy and meets the requirements of personnel positioning in underground mines.

(Invited) Drug Delivery System of Photoresponsive Donor-Acceptor-Linked Molecules to Mouse Retina

Neurotransmission is mediated by electrical pulses that are generated by coordinated activation and deactivation of ion channels in the plasma membrane of neuronal cells. The ion channels control the plasma membrane potential (V m) by influx/efflux of ions. In our retina, the V m is controlled by light and photo-excitable ion channels in photoreceptor cells and voltage-dependent ion channels in neuronal ganglion cells, which transmit visual signal to the brain. In contrast, patients with visual impairment and blindness, e.g., with age-related macular degeneration, lose response to light due to irreversible elimination of photoreceptor cells. Therefore, restoring vision is potentially possible by direct photoexcitation of neuronal ganglion cells with photoresponsive V m-controlling molecules. As one of such molecules, we have focused on donor-acceptor-linked molecules (D–A molecules) capable of photoinduced intramolecular long-lived charge separation [1–4]. In this symposium, I will introduce my recent research mainly on drug delivery system of D–A molecules to the retina in mice [5].REFERENCES[1] Imahori, H. et al., J. Am. Chem. Soc. 2001, 123, 2607–2617.[2] Numata, T. et al., J. Am. Chem. Soc. 2012, 134, 6092–6095.[3] Takano, Y. et al., Chem. Sci. 2016, 7, 3331–3337.[4] Numata, T. et al., Cell. Physiol. Biochem. 2020, 54, 899–916.[5] Fukuda, R. et al., Adv. Therap. 2023, 6, 2300186.

LightNet: A Novel Lightweight Convolutional Network for Brain Tumor Segmentation in Healthcare.

Diagnosis, treatment planning, surveillance, and the monitoring of clinical trials for brain diseases all benefit greatly from neuroimaging-based tumor segmentation. Recently, Convolutional Neural Networks (CNNs) have demonstrated promising results in enhancing the efficiency of image-based brain tumor segmentation. Most current work on CNNs, however, is devoted to creating increasingly complicated convolution modules to improve performance, which in turn raises the computing cost of the model. This work proposes a simple and effective feed-forward CNN, LightNet (Light Network). Based on multi-path and multi-level, it replaces traditional convolutional methods with light operations, which reduces network parameters and redundant feature maps. In the up-sampling stage, a light channel attention module is added to achieve richer multi-scale and spatial semantic feature information extraction of brain tumor. The performance of the network is evaluated in the Multimodal Brain Tumor Segmentation Challenge (BraTS 2015) dataset, and results are presented here alongside other high-performing CNNs. Results show comparable accuracy with other methods but with increased efficiency, segmentation performance, and reduced redundancy and computational complexity. The result is a high-performing network with a balance between efficiency and accuracy, allowing, for example, better energy performance on mobile devices.

Postfilament-Induced Two-Photon Fluorescence of Dyed Liquid Aerosol Enhanced by Structured Femtosecond Laser Pulse

Laser-induced fluorescence spectroscopy (LIFS) is actively used for remote sensing of atmospheric aerosols and is currently one of the most sensitive and selective techniques for determining small concentrations of substances inside particles. The use of high-power femtosecond laser sources for LIFS-based remote sensing of aerosols contributes to the development of new-generation fluorescence atmospheric lidars since it makes it possible to overcome the energy threshold for the nonlinear-optical effects of multiphoton absorption in particles and receive the emission signal at long distances in the atmosphere. Our study is aimed at the development and experimental demonstration of the technique of nonlinear laser-induced fluorescence spectroscopy (NLIFS) based on the remote excitation of aerosol fluorescent emission stimulated by a spatially structured high-power femtosecond laser pulse. Importantly, for the first time to our knowledge, we demonstrate the advances in using stochastically structured plasma-free intense light channels (postfilaments) specially formed by the propagation of femtosecond laser radiation through a turbulent air layer to improve NLIFS efficiency. A multiple increase in the received signal of two-photon-excited fluorescence of polydisperse-dyed aqueous aerosols by the structured postfilaments is reported.

Exploring hormonal regulation and candidate genes in leaflet nyctinasty of Averrhoa carambola

Averrhoa carambola, a commonly cultivated tree, exhibits leaflet nyctinastic movement. However, the underlying mechanism remains unclear. The pulvinus, as a motor organ, coordinates the motion of its attached leaflet. During the leaflet expansion, flexor cells shift from contraction to expansion, with concurrent expansion and fusion of vacuole. In contrast, the extensor cells move from expansion to contraction, causing vacuole contraction and increased vacuole numbers. During the process of leaflet expansion and closure, the contents of IAA and IPA in flexor muscles increased significantly, but did not show significant changes in extensor muscles, BR content showed an opposite trend in extensor and flexor muscles, and the content of ZR increased significantly in extensor muscles but decreased significantly in flexor muscles, and ZR content only decreased in extensor muscles, but did not show significant changes in flexor muscles. Exogenous IAA (50–100 μM) significantly aids in leaflet unfolding during night time. Transcriptome analysis reveals gene enrichment in circadian rhythms, hormone signaling, ion channels, and other pathways during leaflet opening and closure. The expression of AcaCRY3, AcaPHOT1–1, AcaAPRR2, AcaLHY, and AcaAKT1–1 is prominent during expansion, while AcaAUX22–1 stands out during closure. These findings suggest a potential regulatory pathway in A. carambola 'Daguo Tianyangtao 2′ leaflets, involving light, circadian rhythm, hormone signaling, and ion channels. Findings of this study can do a great deal to broaden the plant nyctinastic movement research.

Fabrication of CdS NRs /MoS2@g-C3N4 nanotubes for efficient photoelectrochemical hydrogen production

Exploration of noble metal-free and highly efficient photoelectrocatalyst for hydrogen production attracts the attention of researchers. The graphitic carbon nitride nanotubes, cadmium sulfide nanorods (NRs) and molybedun disulfide, CdS NRs/MoS2@g-C3N4 nanotubes were synthesized via facile hydrothermal method for hydrogen production studies. The synthesized CdS NRs/MoS2@g-C3N4 nanotubes were studied for electrochemical hydrogen production applications. Structural data revealed that the synthesized composite materials attained crystallinity. Electrochemical investigations demonstrated the highest hydrogen production efficiency of CdS NRs/MoS2@g-C3N4 nanotubes as compared to the bare graphitic carbon nitride nanotubes. This seems that the modification of g-C3N4 NTs with MoS2 increased the photocatalytic efficiency of g-C3N4 NTs. The good efficiency of the CdS NRs/MoS2@g-C3N4 NTs is owing to a unique tubular structure, the presence of active sites, light reflection channel, nanotube composite heterostructure, electron-hole separation, better charge transfer and the synergistic effect. Moreover, it was observed that the tubular structure would be the best photoelectrocatalyst for hydrogen production achieving a geometric current density of 10 mAcm−2 at an overpotential of 0.81 V gives 144 mVdec−1 in 1 M KOH versus the RHE. These results may provide insights into constructing highly efficient photoelectrocatalysts by varying the structural morphology and heterojunction for hydrogen production.

Research on channel modeling technology of visible light communication system based on the ray tracing method

Abstract Visible Light Communication (VLC) is a new mode that combines lighting and communication. Because it can meet the needs of large capacity and ultra-high transmission rate, effective analysis of indoor visible light channel characteristics can better provide VLC systems. We provide a reference basis for the design, and VLC technology using Light Emitting Diode (LED) as the light source has become one of the research hotspots in the field of wireless communications. To solve the problems of existing indoor visible light channel modeling methods such as being ideal, high complexity, or poor in versatility, this paper researches indoor visible light communication channel modeling and related theories and methods, using rays with strong scene adaptability. Based on the tracking method, starting from the need to reduce computational complexity and improve tracking accuracy, a channel modeling method for indoor visible light communication is designed. We propose a high-precision indoor visible light communication channel modeling method that combines central ray tubes and bidirectional ray tracing. We use the forward ray tracing method to model indoor visible light communication channels. The simulation experimental results show that the channel modeling method proposed in this article can effectively improve modeling efficiency.

Extending femtosecond laser superfilamentation in air with a multifocal phase mask

Laser filamentation is a spectacular phenomenon where the self-focusing of the laser pulse generates ionizing light channels. Many applications of filamentation, such as the laser lightning rod, require the generation of superfilaments, long plasma channels of higher electron density than normal filaments. Using a multifocal phase mask, we demonstrate an extension of the superfilamentation length of a focused terawatt laser beam. Optimized superfilaments show increased energy deposition compared to a normal gaussian beam and an extension of their length by at least a factor two. When put in contact with a high voltage electrode, the guiding of a single plasma column with a length of ∼1 m is observed. The length of an air waveguide generated by a vortex laser pulse is also increased by a factor 2 in the presence of the phase mask.

A 930 m/180 Gbps*User Underwater Coherent Optical Code-Division Multiple-Access Network Based on Hybrid 256-Differential Pulse Position Modulation and Weighted Modified Prime Code Sequence

Currently, there are three types of optical communication networks based on the communication channel between the transmitter and receiver: the optical fiber channel, visible light channel, and optical wireless channel networks. The last type has several advantages for underwater communication, wireless sensors, and military communication networks. However, this type of optical network suffers from weather conditions in free-space communications and attenuation owing to the scattering and absorption mechanisms for underwater communication. In this study, we present a new transceiver architecture of a coherent optical code-division multiple-access (OCDMA) system based on a hybrid M-ary differential pulse position modulation scheme and a spreading code sequence called weighted modified prime code for underwater communication to minimize channel dispersion, increase the transmission rate per second, enhance the network bit error rate (BER) performance, and improve network security. Using an OCDMA system, we can simultaneously expand the network coverage area and increase the number of users sharing the network over the same channel bandwidth. The simulation results in this study proved that the proposed system can accommodate 1310 active users and a network throughput of 180 Gbps*user over a transmission distance of 930 m without any repeater at a 10−9 BER performance, compared to the 45 Gbps*user network throughput and 100 m transmission distance reported in the literature.

A compact microfluidic laser-induced fluorescence immunoassay system using avalanche photodiode for rapid detection of alpha-fetoprotein.

Alpha-fetoprotein (AFP), commonly employed for early diagnosis of liver cancer, serves as a biomarker for cancer screening and diagnosis. Combining the high sensitivity and specificity of fluorescence immunoassay (FIA), developing a low-cost and efficient immunoassay system for AFP detection holds significant importance in disease diagnosis. In this work, we developed a miniaturized oblique laser-induced fluorescence (LIF) immunoassay system, coupled with a microfluidic PMMA/paper hybrid chip, for rapid detection of AFP. The system employed an avalanche photodiode (APD) as the detector, and implemented multi-level filtering in the excitation light channel using the dichroic mirror and optical trap. At first, we employed the Savitzky-Golay filter and baseline off-set elimination methods to denoise and normalize the original data. Then the cutoff frequency of the low-pass filter and the reverse voltage of the APD were optimized to enhance the detection sensitivity of the system. Furthermore, the effect of laser power on the fluorescence excitation efficiency was investigated, and the sampling time during the scanning process was optimized. Finally, a four-parameter logistic (4PL) model was utilized to establish the concentration-response equation for AFP. The system was capable of detecting concentrations of AFP standard solution within the range of 1-500 ng/mL, with a detection limit of 0.8 ng/mL. The entire immunoassay process could be completed within 15 min. It has an excellent potential for applications in low-cost portable diagnostic instruments for the rapid detection of biomarkers.

Dual-Channel/Localization Single-Molecule Fluorescence Probe for Monitoring ATP and HOCl in Early Diagnosis and Therapy of Rheumatoid Arthritis.

Rheumatoid arthritis (RA), a common chronic inflammatory illness, is still incurable, reducing the sufferers' quality of life significantly. Adenosine 5'-triphosphate (ATP) and hypochlorous acid (HOCl) are key indicators in RA, but their precise mechanisms in RA pathophysiology are unknown. As a result, in order to detect ATP and HOCl simultaneously, we created two new dual-channel/localization single-molecule fluorescence probes, RhTNMB and RhFNMB. Furthermore, RhFNMB outperformed RhTNMB in terms of detection performance. ATP and HOCl produce independent fluorescence responses in the light red channel (λex = 520 nm, λem = 586 nm) and deep red channel (λex = 620 nm, λem = 688 nm), respectively, without spectral crosstalk. It should be noted that the probe RhFNMB successfully imaged ATP in mitochondria and HOCl in cells. Surprisingly, the probe RhFNMB demonstrated remarkable detection ability in the diagnosis and treatment of Pseudomonas aeruginosa-induced abdominal inflammation in mice. We continued to apply the probe RhFNMB to track ATP and HOCl in RA and discovered that ATP and HOCl concentrations were considerably greater in RA joints than in normal joints. We also confirmed the therapeutic effect of methotrexate on RA. This study is the first to achieve dual-channel imaging of ATP and HOCl, which is of great value for the early diagnosis and therapy of RA.