- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Sensing of airborne molecular contaminants based on microfiber coupler with mesoporous silica coating
摘要： Airborne molecular contaminants (AMCs) are critical issues for the performance of optics in high power lasers (HPLs). In this work we demonstrate an AMCs sensor based on an optical microfiber coupler (OMC) with mesoporous silica coating experimentally. AMCs adhered on the mesoporous silica coating modifies the surrounding refractive index (RI). Using Beam Propagation Method (BPM), the proposed structure was analyzed to demonstrate the feasibility of AMCs sensing. By coating a mesoporous silica layer on the surface of sensing area, the proposed structure was able to operate as an AMCs sensor. By monitoring the spectral shift in the wavelength domain, the sensor was shown to be capable of detecting concentration of AMCs. The experimental results show that the sensitivity of the sensor is concentration-dependent. The maximum sensitivity of 0.541nm/(mg/m3) is achieved. The detected signal is found to be proportional to AMCs present.
关键词： Airborne molecular contaminants (AMCs),Beam propagation method,Optical microfiber coupler (OMC),Evanescent field
更新于2025-09-23 15:22:29
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Stilbene derivative as a photosensitive compound to control the excitability of neonatal rat cardiomyocytes
摘要： Substances that can be used as photosensitizers for cardiac tissue are very helpful in modeling various excitation patterns in a cardiac tissue culture and may have prospective use in the temporary and permanent ablation of unwanted excitation sources in the heart. The aim of the present work is to study the effect of stilbene derivative c-TAB (2- {4- [(E) -2- (4-ethoxyphenyl) vinyl] phenoxy} ethyl) trimethylammonium bromide) on the cardiomyocyte layers and voltage-gated ion channels in cardiac cells. C-TAB is a structural analogue to AzoTAB, reported previously as a photoswitch for cardiac and neural cells, in which the azobenzene moiety is replaced by a stilbene grouping. Such a replacement makes c-TAB less toxic to living cells. c-TAB has been shown to successfully inhibit excitation in cardiac cells in both trans- and cis- forms. The excitation inhibition of cardiac cells under c-TAB is reversible and can be overturned easily by washing out the c-TAB; however, not by light illumination. The irradiation of cardiac cells with near-UV when the trans- form of c-TAB is applied changes reversible inhibition to a permanent one that cannot be overturned by a washout.
关键词： Excitation wave propagation,Stilbene derivative,Voltage-gated Ion channels,Neonatal rat cardiomyocyte
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Novel Quick and Precise Method for Evaluating Optical Characteristics
摘要： We describe a new test element and method for evaluating optical characteristics such as a propagation loss. The test element is simply composed of a grating coupler, an interferometer, and an integrated photodetector. The propagation loss is accurately derived by a few elements. This method has potential for drastically reducing measurement time in wafer-level inspection.
关键词： on-wafer testing,propagation loss,grating coupler,photodetector
更新于2025-09-23 15:22:29
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Superpositions of Gaussian beams and column Gaussian packets in heterogeneous anisotropic media
摘要： Based on the integral superposition of Gaussian packets, we derive the equations for the integral superposition of Gaussian beams and for the integral superposition of column Gaussian packets in smoothly heterogeneous media. Whereas Gaussian beams extend along their central rays, column Gaussian packets extend along an arbitrary system of lines. The equations are applicable to both the anisotropic ray theory and the coupling ray theory in anisotropic media, or to the isotropic ray theory in isotropic media. The superpositions corresponding to the coupling ray theory can be applied to various kinds of reference rays. The equations can be used in both Cartesian and curvilinear coordinates.
关键词： Electromagnetic anisotropy,Seismic attenuation,Body waves,Theoretical seismology,Wave propagation,Seismic anisotropy
更新于2025-09-23 15:22:29
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Measurements of Beamswitching Gains and Fade Dynamics for 28 GHz Indoor Static Links in the Presence of Pedestrian Traffic
摘要： We measured channel dynamics for fixed wireless indoor channels at 28 GHz. We characterize pedestrian-induced fades in open indoor spaces and the effectiveness of beamswitching to mitigate them. We find that fades of the dominant propagation path may be as deep as 9 dB at the 90th percentile and that alternative signal paths are typically not strong enough to provide significant beamswitching gains.
关键词： Millimeter wave propagation,Rician channels,Channel models,Multipath channels,Fading channels
更新于2025-09-23 15:22:29
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Optical orbital angular momentum under strong scintillation
摘要： The evolution of classical optical fields propagating through atmospheric turbulence is investigated under arbitrary conditions. We use the single-phase screen (SPS) method and the infinitesimal propagation equation (IPE), a multiphase screen (MPS) method, to compute the optical power fractions retained in an input Laguerre-Gauss (LG) mode or transferred to higher-order LG modes. Although they show the same trend while the scintillation is weak, the IPE and SPS predictions deviate when the strength of scintillation passes a certain threshold. These predictions are compared with numerical simulations of optical fields propagating through turbulence. The simulations are performed using an MPS model, based on the Kolmogorov theory of turbulence, for different turbulence conditions to allow comparison in both weak and strong scintillation. The numerical results agree well with the IPE results in all conditions, but they deviate from the SPS results for strong scintillation.
关键词： multiphase screen method,scintillation,infinitesimal propagation equation,atmospheric turbulence,Laguerre-Gauss modes,single-phase screen method,optical orbital angular momentum
更新于2025-09-23 15:22:29
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[IEEE 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Athens, Greece (2018.7.4-2018.7.6)] 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Depth Estimation and Ray Tracing Model Selection of Buried Utilities on Ground Penetrating Radar Data
摘要： When assessing a target depth from a Ground Penetrating Radar (GPR) image, one typically assumes a certain wave propagation model as well as the model parameters (typically the dielectric of the medium). While much work has been conducted on the automatic inference of the model parameters, not much work has been performed testing the validity of the model itself. The work presented here closes this gap for a low-frequency GPR system (350 MHz center frequency). It compares the measurement, taken from known targets at known depths, with different ray propagation models. It also presents a novel method for efficiently estimating the depth of a target without using any knowledge of the medium's wave propagation speed, or even the time of the signal's emission from the transmitter (time zero). Experiments on 26 targets of varying depths showed an averaged estimation error of less than 0.5%, with a standard deviation of 3% using this robust and efficient method.
关键词： GPR,Wave Propagation,Ray Tracing Models,Target Depth Estimation
更新于2025-09-23 15:22:29
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Fast Method to Optimize RF Bumper Transparency for Wide-Band Automotive Radar
摘要： This article describes novel methods to enhance the RF integration of wideband automotive radars. The first part of the paper is introducing the context and the considered scenario. Whereas the second part is focusing on two solutions to improve the radar integration in car chassis environment. The aim is to have good RF performances on wideband operation (76–81 GHz) and on a wide range of angle of incidence for the radar having wide field of view (e.g. Blind spot radar, Pedestrian detection,…).
关键词： transmission,metamaterial,reflection,radome,propagation,ACC radar
更新于2025-09-23 15:22:29
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Pulse delay and group velocity dispersion measurement in V-type electromagnetically induced transparency of hot <sup>85</sup>Rb atom
摘要： Pulse delay with the group velocity dispersion (GVD) characteristics was studied in the V-system configuration. The phase coherency between the pump and the probe laser beams was maintained. We studied the pulse delay and the GVD characteristics with the variation of the type electromagnetically induced transparency in the hyperfine levels of 85Rb atoms with a closed electromagnetically induced transparency of hot 85Rb atom. For a better understanding of the experimental results, we have derived an analytical solution for the three level V-type system. The theoretical plots of the delay and the group velocity dispersion show the same characteristics as we observed in the experiment. This analytical approach can be further generalized for the higher level schemes to calculate different quantities such as susceptibility, group velocity delay or group velocity dispersion characteristics.
关键词： electromagnetically induced transparency,Coherent optical effects,Pulse propagation and temporal solitons
更新于2025-09-23 15:21:21
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On Geometric Optics over a Spherical Earth With an Exponential Refraction Index
摘要： The ray based method of geometrical optics can be used for wave propagation a over spherical earth with good results. A previous such a method also includes an exponential refraction index. This method gives good results for large terminal heights and distances, but for small distances, it has some shortcomings. In this paper, an improvement is proposed which remove these shortcomings. Also, as the method depends on numerical procedures, some improved numerical calculations are put forward.
关键词： refraction,geometrical optics,Electromagnetic propagation
更新于2025-09-23 15:21:21