Transmission Matrix Method Research Articles

Using GIS Remote Sensing Image Data for Wetland Monitoring and Environmental Simulation.

Through a comprehensive theoretical basis and actual test analysis of the application system design and functional efficiency of the cloud platform, this paper puts forward an artificial intelligence environmental data monitoring and wetland environmental simulation method based on GIS remote sensing images. First, the basic storage and computing functions have been enhanced at the physical layer. Second, the middleware layer is more flexible in the use of management methods and strategies. There are many strategies and methods that can be used in combination. Finally, based on this, the application system design framework is more convenient and faster so that you can focus on business logic, and the strategic advantages of certain functions are very obvious. The method of object-oriented classification and visual interpretation using UAV image data and satellite remote sensing images from the typical recovery area and treatment area of wetland from 2016 to 2020 is given in detail together to extract wetland information and use GIS software for dynamic calculation. Using the wetland transmission matrix method, the distribution map of the characteristic types of the survey areas in the four periods and the conversion status of the characteristic types at each stage were obtained, and the effect of wetland treatment was quantitatively studied.

Research on photoacoustic microscopy imaging based on photoacoustic transmission matrix with a digital micromirror device

Due to the high penetrability of ultrasonic signals in scattering media, photoacoustic imaging based on photoacoustic effect is of great significance in the research of non-destructive testing and imaging of biological tissues. However, multiple light scattering will occur after the laser is incident on the scattering medium, resulting in poor imaging quality or inability to image. In this paper, we propose a novel method for wavefront shaping and photoacoustic imaging based on a photoacoustic transmission matrix. We use the photoacoustic transmission matrix method as the algorithm for wavefront shaping, and combine the superpixel method with a digital micromirror device (DMD) to modulate the amplitude and phase of the incident light, resulting in an enhancement factor of 10.75 for the photoacoustic signal. Then, we realize photoacoustic scanning imaging by moving the two-dimensional translation stage to drive the absorber above. Compared with the inability to image the initial photoacoustic signal before shaping, the shaped photoacoustic signal can obtain a clear photoacoustic image with a contrast ratio of 16.85. The wavefront shaping and photoacoustic imaging of photoacoustic signals based on photoacoustic transmission matrix method have a good prospect in the imaging of weaker photoacoustic signals.

Boosted Efficiency Over 18.1% of Polymer Solar Cells by Employing Large Extinction Coefficients Material as the Third Component

A series of binary and ternary polymer solar cells (PSCs) is successfully fabricated. The optimal ternary PSCs achieve a power conversion efficiency (PCE) of 18.14%, benefiting from the increased short circuit current density (JSC ) of 26.53 mA cm-2 and fill factor (FF) of 78.51% in comparison with the JSC s (25.05 mA cm-2 and 25.65 mA cm-2 ) and the FFs (77.13% and 76.55%) of the corresponding binary PSCs. The photon harvesting ability of ternary active layers can be enhanced, which can be confirmed from the EQE spectral difference of the optimized ternary and binary PSCs, especially in the wavelength range from 680 nm to 800 nm. The refractive index and extinction coefficients of binary and ternary blend films are measured, which can well support the enhanced photon harvesting ability in different wavelength ranges. Photogenerated exciton distribution in active layers is simulated by the transmission matrix method based on the Beer-Lambert law. The photogenerated exciton density can be enhanced in the middle of the active layers by incorporating a third component in acceptors, which is conducive to charge collection by individual electrodes, resulting in the simultaneously enhanced JSC and FF of the optimal ternary PSCs.

Design, Simulation, and Optimization of Polarization-Independent Four-Port Optical Waveguide Circulator Based on a Ferrite Material

Optical circulators are used in optical devices such as multiplexers, demultiplexers, and optical routers. Usually, the magnetic material in the center of the circulator conducts light by interacting with the electromagnetic wave. In this research, a polarization-independent four-port optical waveguide circulator with the presence of a rhombus-shaped ferrimagnetic material has been designed, simulated, and optimized in the three-dimensional part of Comsol software. This designed circulator unlike the previous structures has four ports which use the transmission matrix method to conduct waves. By selecting the appropriate size and type of central ferrite, as well as the scale of input and output channels, the most optimal situation is obtained for power transmission with less than 1 dB loss when port 1 is input and port 2 is output.

Recognition of fractional orbital angular momentum modes under scattering with transmission matrix

Vortex beams carrying fractional orbital angular momentum (FOAM) mode show great potential in optical encryption, anisotropic edge enhancement, optical communication, etc. However, the small mode interval of FOAM makes it sensitive to transmission scattering, which distorts the helical phase-front and leads to substantial mode crosstalk. Herein we propose a transmission matrix method to recognize FOAM modes under scattering. By constructing the linear relationship between the input and scattering field, a transmission matrix retrieval algorithm was used to recover the helical phase-front of the vortex beam from its intensity distribution, and FOAM mode was recognized via the phase period. We showed that FOAM modes under scattering are successfully recognized with an accuracy of >99.8%. As a proof-of-concept, a 100 × 100 pixel image was transmitted and recovered in a high scattering. Our results indicate that the transmission matrix method presents a new approach to recognize FOAM modes under scattering, which may benefit various FOAM applications.

Hyperspectral imaging through scattering layers with incoherent light

Overcoming the light scattering for imaging under natural light conditions is a tough question to solve. One major issue is the absence of an efficient model to characterize the spectral features of incoherent light scattering. Here, we put forward the incoherent light transmission matrix (TM) approach in thin scattering layers. The proposed model is a unique form of TM that characterizes the spectral transmission feature of a system with multiple spatial transmission modes. With this method, we recover hyperspectral information from a single-shot monochromatic light spot without any additional dispersion or imaging elements. The proposed TM method can also be extended to recover other information from the light field, such as the polarization information without the use of a traditional polarizer. Our method also outperforms traditional optimization algorithms in terms of time and memory cost. The results demonstrate the feasibility of our method for retrieving the abundant information from natural light scattering with the help of simple optical setups.

Learning to image and compute with multimode optical fibers

Abstract Multimode fibers (MMF) were initially developed to transmit digital information encoded in the time domain. There were few attempts in the late 60s and 70s to transmit analog images through MMF. With the availability of digital spatial modulators, practical image transfer through MMFs has the potential to revolutionize medical endoscopy. Because of the fiber’s ability to transmit multiple spatial modes of light simultaneously, MMFs could, in principle, replace the millimeters-thick bundles of fibers currently used in endoscopes with a single fiber, only a few hundred microns thick. That, in turn, could potentially open up new, less invasive forms of endoscopy to perform high-resolution imaging of tissues out of reach of current conventional endoscopes. Taking endoscopy by its general meaning as looking into, we review in this paper novel ways of imaging and transmitting images using a machine learning approach. Additionally, we review recent work on using MMF to perform machine learning tasks. The advantages and disadvantages of using machine learning instead of conventional methods is also discussed. Methods of imaging in scattering media and particularly MMFs involves measuring the phase and amplitude of the electromagnetic wave, coming out of the MMF and using these measurements to infer the relationship between the input and the output of the MMF. Most notable techniques include analog phase conjugation [A. Yariv, “On transmission and recovery of three-dimensional image information in optical waveguides,” J. Opt. Soc. Am., vol. 66, no. 4, pp. 301–306, 1976; A. Gover, C. Lee, and A. Yariv, “Direct transmission of pictorial information in multimode optical fibers,” J. Opt. Soc. Am., vol. 66, no. 4, pp. 306–311, 1976; G. J. Dunning and R. Lind, “Demonstration of image transmission through fibers by optical phase conjugation,” Opt. Lett., vol. 7, no. 11, pp. 558–560, 1982; A. Friesem, U. Levy, and Y. Silberberg, “Parallel transmission of images through single optical fibers,” Proc. IEEE, vol. 71, no. 2, pp. 208–221, 1983], digital phase conjugation [I. N. Papadopoulos, S. Farahi, C. Moser, and D. Psaltis, “Focusing and scanning light through a multimode optical fiber using digital phase conjugation,” Opt. Express, vol. 20, no. 10, pp. 10583–10590, 2012; I. N. Papadopoulos, S. Farahi, C. Moser, and D. Psaltis, “High-resolution, lensless endoscope based on digital scanning through a multimode optical fiber,” Biomed. Opt. Express, vol. 4, no. 2, pp. 260–270, 2013] or the full-wave holographic transmission matrix method. The latter technique, which is the current gold standard, measures both the amplitude and phase of the output patterns corresponding to multiple input patterns to construct a matrix of complex numbers relaying the input to the output [Y. Choi, et al., “Scanner-free and wide-field endoscopic imaging by using a single multimode optical fiber,” Phys. Rev. Lett., vol. 109, no. 20, p. 203901, 2012; A. M. Caravaca-Aguirre, E. Niv, D. B. Conkey, and R. Piestun, “Real-time resilient focusing through a bending multimode fiber,” Opt. Express, vol. 21, no. 10, pp. 12881–12887; R. Y. Gu, R. N. Mahalati, and J. M. Kahn, “Design of flexible multi-mode fiber endoscope,” Opt. Express, vol. 23, no. 21, pp. 26905–26918, 2015; D. Loterie, S. Farahi, I. Papadopoulos, A. Goy, D. Psaltis, and C. Moser, “Digital confocal microscopy through a multimode fiber,” Opt. Express, vol. 23, no. 18, pp. 23845–23858, 2015]. This matrix is then used for imaging of the inputs or projection of desired patterns. Other techniques rely on iteratively optimizing the pixel value of the input image to perform a particular task (such as focusing or displaying an image) [R. Di Leonardo and S. Bianchi, “Hologram transmission through multi-mode optical fibers,” Opt. Express, vol. 19, no. 1, pp. 247–254, 2011; T. Čižmár and K. Dholakia, “Shaping the light transmission through a multimode optical fibre: complex transformation analysis and applications in biophotonics,” Opt. Express, vol. 19, no. 20, pp. 18871–18884, 2011; T. Čižmár and K. Dholakia, “Exploiting multimode waveguides for pure fibre-based imaging,” Nat. Commun., vol. 3, no. 1, pp. 1–9, 2012; S. Bianchi and R. Di Leonardo, “A multi-mode fiber probe for holographic micromanipulation and microscopy,” Lab Chip, vol. 12, no. 3, pp. 635–639, 2012; E. R. Andresen, G. Bouwmans, S. Monneret, and H. Rigneault, “Toward endoscopes with no distal optics: video-rate scanning microscopy through a fiber bundle,” Opt. Lett., vol. 38, no. 5, pp. 609–611, 2013].

The dynamic stiffness matrix method for seismograms synthesis for layered transversely isotropic half-space

Natural rocks and soils show significant anisotropic behavior owing to sedimentation and weathering, particularly apparent in the crust. However, seismograms synthesis for the anisotropic medium is scarce, especially bottlenecks for large-scale and broadband seismic wave propagation. In this paper, seismogram synthesis for a multi-layered transversely isotropic half-space due to seismic point sources is addressed by using a dynamic stiffness matrix method. The critical step of the proposed method lies in the construction of the global dynamic stiffness matrix in frequency-wavenumber domain, which avoids the accumulation of errors that appeared in the reflection and transmission matrix method. Exponential divergent terms related to wavenumber and layer thickness in dynamic stiffness matrix are extracted for fast simulating large-scale and high-frequency wavefield. The seismic point sources are equated to the external loads imposed at the introduced auxiliary surfaces, through which the dynamic stiffness matrix can be utilized to obtain the solutions. The accuracy is verified by comparing the proposed method results with three examples in the publications, involving different source types and depth scales. Two numerical examples regarding Thomsen parameters are given to illustrate the mechanism of wave propagation and ground motion in an anisotropic media. Numerical results show that the anisotropic characteristics affect the wave propagation time, waveform and wave-front energy distribution, further leading to shear wave splitting phenomena, which remarkably differ from the isotropic case. A case study using a simplified three-layered crustal structure model in Tibet elucidates that peak ground displacement and its distribution difference within the epicenter of 10 km by comparing with the equivalent isotropic model without considering anisotropic properties. The results show a 10.91% deviation in the location of the peaks, with amplitude differences of up to 120% due to a 45° dip-slip source at different frequencies (from 1 Hz to 15 Hz).

Shaping the illumination beams for STED imaging through highly scattering media

Stimulated emission depletion (STED) microscopy has been widely applied in single-cell and single-molecular studies benefiting from its ability of super-resolution imaging. However, it is challenging to perform STED imaging in highly scattering media, such as biological tissues, due to high scattering, which destroys the structured illumination beams. Here, we present a technique to produce the desired illumination beams beyond high scattering for STED microscopy. A dual-wavelength transmission matrix method is employed for shaping the excitation beam and the STED beam simultaneously, achieving the temporal and spatial overlap of the two beams behind a scattering medium. Experimentally, the overlapped foci were constructed by using a digital micromirror device (DMD). The extinction ratio of the STED focus reaches −23.8 dB, which compares favorably to the oft-quoted desirable value for STED applications. In particular, raster scanning of overlapped foci and the switching of the STED focus were demonstrated by adopting the fast switching ability of the DMD. Construction of the illumination beams beyond scattering will benefit STED microscopy in deep tissues.

Mode engineering of semiconductor lasers with vertical periodic layered structures

High-power and low-divergence semiconductor lasers are useful in light detection and ranging, as well as material processing and so on. In this paper, an efficient approach is presented to explain the physics of mode selection in semiconductor lasers with vertical periodic layers for high power and low vertical beam divergence. The transmission matrix method is used to obtain the allowed band and forbidden band of the vertical periodic layered structure, and the band diagram of the layered structure of the semiconductor laser. The fundamental mode of the layered structure of the semiconductor laser lies in the forbidden band of the vertical periodic layered structure. Tapered lasers based on the designed layered structure are fabricated and can achieve an output power of 2.45 W. The measured vertical divergence angle of the tapered laser is below 10°, consistent well with the calculated result of 9.5°.

Study of Forward and Backward Modes in Double-Sided Dielectric-Filled Corrugated Waveguides.

This work studies the propagation characteristics of a rectangular waveguide with aligned/misaligned double-sided dielectric-filled metallic corrugations. Two modes are found to propagate in the proposed double-sided configuration below the hollow-waveguide cutoff frequency: a quasi-resonant mode and a backward mode. This is in contrast to the single-sided configuration, which only allows for backward propagation. Moreover, the double-sided configuration can be of interest for waveguide miniaturization on account of the broader band of its backward mode. The width of the stopband between the quasi-resonant and backward modes can be controlled by the misalignment of the top and bottom corrugations, being null for the glide-symmetric case. The previous study is complemented with numerical results showing the impact of the height of the corrugations, as well as the filling dielectric permittivity, on the bandwidth and location of the appearing negative-effective-permeability band. The multi-modal transmission-matrix method has also been employed to estimate the rejection level and material losses in the structure and to determine which port modes are associated with the quasi-resonant and backward modes. Finally, it is shown that glide symmetry can advantageously be used to reduce the dispersion and broadens the operating band of the modes.

A unified description of surface waves and guided waves with relative amplitude dispersion maps

SUMMARYCompared with surface waves, guided waves are rarely applied in near-surface investigation. The main reason may lie in the complexity of their dispersion curves. Besides, the study and understanding of guided wave dispersion characteristics are now also inadequate and not deep enough. In this paper, we derived the complete theoretical dispersion curves of P–SV-wave and pure P-wave systems in layered media based on the transmission matrix method and obtained the relative displacement amplitude coefficients at the free surface as a function of frequency and phase velocity for both surface and guided waves. By assigning the value of relative displacement amplitude coefficient to the corresponding point (f,v) on dispersion curve, we got a multi-information diagram called relative amplitude dispersion map (RADM). As a unified description of surface and guided waves, RADM not only shows the velocity–frequency relationship but also represents the polarized energy ratio at the free surface by display colours. The accuracy of RADM was proved by synthetic seismic records, in which RADMs fit well with the corresponding dispersion energy of surface and guided waves. In addition, we designed six models with different Poisson's ratio (PR) and different layer numbers for comparison. It shows that the dispersive vertical-to-horizontal amplitude ratio of guided waves is complex and discontinuous in RADM, which brings great difficulty for mode identification and even affects the subsequent inversion. Tests also show that for high PR layers, the trends of guided P–SV-wave dispersion curves are basically consistent with those of pure P wave. With the decrease of PR, dispersion curves of guided P–SV wave gradually deviate from those of pure P wave. However, RADMs can be greatly consistent with the dispersion energy in either case. This is of great significance for the inversion of near-surface P and S velocities by using dispersion relationships of multimode surface and guided waves.

An Experimental Study on the Performance of Corrugated Cardboard as a Sustainable Sound-Absorbing and Insulating Material

The continuing development of industrialization and increasing population density has led to the emergence of noise as an increasingly common problem, requiring various types of sound absorption and insulation methods to address it. Meanwhile, the recycling of resources to ensure a sustainable future for the planet and mankind is also required. Therefore, this study investigates the potential of corrugated cardboard as a resource for noise reduction. The sound absorption and insulation performance of non-perforated corrugated cardboard (NPCC) were measured, and modified corrugated boards were fabricated by drilling holes either through the surface of the corrugated board alone or through the corrugated board in its entirety. The sound-absorption/insulation performance both of perforated corrugated cardboard (PCC) and perforated corrugated cardboard with multi-frequency resonators (PCCM) were measured using the transfer function method and the transmission matrix method. To determine the effectiveness of NPCC, PCC, and PCCM in noise reduction, the sound pressure level was analyzed by applying it to a home blender. The results showed PCCM’s sound absorption and insulation performance to be excellent. On the basis of these findings, we propose the use of PMMC as an eco-friendly noise-reduction material.

Research on Electromagnetic Wave Propagation and Optical Characteristics Based on Optical Transfer Matrix Method

The processing of electromagnetic waves by means of optical transmission matrix can be applied through multi-layer homogenization media, and finally real-time transmission can be realized. After that, it can derive the transmission matrix based on the interface and propagation matrix construction, and finally obtain the reflection and permeability coefficients. This article summarizes the content of the transmission matrix method based on previous work experience. The author discusses the propagation and optical characteristics of physical electromagnetic waves based on the optical transmission matrix method from four aspects: reflection-increasing film analysis, DBR design, reflectance calculation of fiber multi-directional laminates, plane wave propagation and reflection in the medium.

High‐Fidelity Image Reconstruction through Multimode Fiber via Polarization‐Enhanced Parametric Speckle Imaging

AbstractHigh‐quality signal transmission and imaging through a multimode fiber is essential for optical communications and medical endoscopic imaging, as it can provide high fidelity of the transferred information. Multiple mode superposition and mode coupling distort the incident wave, and a speckle pattern formed at the exit end of a multimode fiber makes the reconstruction of the original object challenging. The transmission matrix method is proposed to characterize the complex mesoscopic optical transmission channels, allowing light to traverse through the random medium. Here, a novel approach, namely polarization‐enhanced parametric speckle imaging, is proposed to improve imaging quality through a multimode fiber by utilizing the properties of polarization evolution through a multimode fiber. The demonstrated superior performance of polarization‐enhanced parametric speckle imaging opens novel avenues for optical communication system and photonics‐based endoscopic diagnosis.

Analysis of the Vibration of the Ground Surface by Using the Layered Soil: Viscoelastic Euler Beam Model due to the Moving Load

Moving loads will have a certain impact on the safety of the structures. Since concrete is a viscoelastic material, the elastic concrete model cannot describe its viscoelastic characteristics under moving loads. It is necessary to establish a model that can describe the viscoelastic characteristics of concrete materials. In addition, the layered of the soil is also an important factor affecting the propagation of subway vibration waves. Considering the effects of the properties of the concrete material of the subway tunnel structure and the layered soil foundation as well as the load velocity on the vibration of the ground surface caused by the moving load, the standard linear elastic solid Euler beam model is described for the subway tunnel structure in this paper. The equivalent stiffness of the layered soil-viscoelastic beam coupling system subjected to a moving load is formed by using the transmission and reflection matrix (TRM) method. The numerical solution of ground surface displacement caused by subway tunnel in time-space domain is obtained by IFFT algorithm. The correctness of the algorithm is verified by comparing with the reference results. Numerical results show that, with the increase of the viscous coefficient of the viscoelastic Euler beam, the vibration amplitude of the ground surface will decrease. Up to a certain value of the increasing the viscous coefficient of the Euler beam, it will have little effect on the vibration amplitude of the ground surface. Therefore, the standard solid model of viscoelastic Euler beam can well describe the creep and relaxation of materials. The model of viscoelastic beam is reasonable for the working condition of subway tunnel concrete structure. At high speed of moving load, the maximum value of ground surface displacement spectrum will appear at the smaller frequency domain and the maximum value of displacement spectrum will also increase for the soft layer soil, while it is opposite to that of the stiffer layer soil.

Design of multi-passband polymer multilayer film and its application in photovoltaic agriculture

To solve the issue of the contradiction between photovoltaic power generation and plant photosynthesis for sunlight demand, we propose a design method of multi-passband polymer multilayer optical structure. Using polycarbonate (PC) and polymethyl methacrylate (PMMA), two polymer materials with different refractive indices, the passband position and passband bandwidth are calculated and adjusted by the transmission matrix method and TFCalc software. A 450 nm, 660 nm, and 730 nm three-passband filter was realized by superimposing stacks of different band positions. The feasibility of the photovoltaic agriculture was confirmed by the power generation efficiency and the actual plant growth.

Transmission matrix method modeling of experimental results of electromagnetic shielding effectiveness of DNA-conductive nanoparticle composites

A transmission matrix method (TMM) commonly used for modeling the electromagnetic properties of multilayered biopolymer/conductive nanoparticle composites is presented, which predicts the behavior of the experimental results of the electromagnetic shielding effectiveness of a deoxyribonucleic acid-silver nanoparticle composite but falls short for accurately predicting the absolute shielding effectiveness. The versatility of the model can handle metamaterials, various incident angles, both TE and TM polarizations, and single and multilayer structures with complex and dispersive permittivity and permeability. We present the simulated results for a single-layer slab using the TMM along with the experimental results. Parametric studies are conducted with the model to investigate the reflection and transmission performance for single-layer slabs by varying the loss tangent, dielectric constant, incident angle, and thickness parameters.

Tunable and asymmetric optical bistability of one-dimensional photonic crystals based on InSb and nonlinear materials.

In this paper, one-dimensional (1D) photonic crystals (PCs) based on InSb and nonlinear materials are studied using the transmission matrix method. It is found that in the terahertz band, due to the magneto-optical characteristics of InSb, when the incident light propagates through such 1D PCs in two different directions (forward and backward propagation), an asymmetric optical bistable state can be obtained. Propagating from the forward direction, the bistable state is achieved. Spreading from the backward direction, the multistable state can be observed. Compared with the bistable threshold value for the case of forward incidence, the similar value that appeared in the multistable curve is significantly reduced. The polarization-sensitive features of the asymmetric optical bistability of the presented 1D PCs are also investigated under TM waves, which focuses on the tuning effects of incident angle, external magnetic field, temperature, and the thicknesses of the InSb and nonlinear dielectric layers on the asymmetric optical bistability. The results show that when the incident light enters from two different directions, the tailoring effects of the incident angle and thickness of the InSb layer on the bistable state are obviously different, but the tuning influences of the magnetic field, temperature, and the thickness of the nonlinear material layer on the bistable state are similar. The asymmetric optical bistability we made in this paper can be applied to multifunctional devices and nonreciprocal optical isolators.

Multichannel filter based on tunable fibonacci quasi-periodic structure for one-dimensional magnetized ternary plasma photonic crystal

In this paper, we propose an one-dimensional magnetized plasma photonic crystal based on the ternary Fibonacci quasi-period structure, and use the transmission matrix method (TMM) to study the terahertz band comb-like multichannel filtering properties, which is different from the periodic structure multichannel properties introduced by the plasma defect or dielectric defect. Second, we give the calculation formula of the transmission matrix of the model, third, we find the numerical relationship between the number of Fibonacci sequences and the number of channels. Higher relative refractive index improves the filter performance of comb-like channels. The effect of the length of each layer on the number of channels and the frequency of adjacent comb-like channels is different from that of traditional periodic multichannel filters. The detuning of magnetic field can increase the number of filtering channels, and different incident angles have different phenomena.