The magnetotelluric transverse electric mode as a natural filter for static effects: Application to the COPROD2 and COPROD2S2 data sets

Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. E91-E99 ◽  
Author(s):  
Enrique Gómez-Treviño ◽  
Francisco J. Esparza ◽  
Yunuhen Muñiz ◽  
Armando Calderón
Keyword(s):  
Electromagnetic Induction ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Data Sets ◽  
Data Set ◽  
Te Mode ◽  
Tm Mode ◽  
Amplitude Data ◽  
Final Interpretation ◽  
Electric Mode

We regard the amplitude of the magnetotelluric impedance of the transverse electric (TE) mode as output, rather than input, in 2D inverse algorithms. The model obtained in the inversion is in this context only an intermediate product whose TE theoretical response is for all intents and purposes the object of the inversion. The input is the amplitude of the transverse magnetic (TM) mode and the phases of both modes. They are fitted as much as possible by relaxing regularization to its limits, allowing the model to include features not strictly required by the data, but still required by the amplitude of the TE curves. We propose two tests to guaranty the accuracy and reliability of the recovery. The first is a convergence test whereby the output is monitored as a function of the roughness of the model. Second, the TM amplitude data are multiplied by different factors and the output is checked for consistency with the previous test. The resulting TE responses have only electromagnetic induction effects and thus are free from static shifts due to electric charges. We apply the procedure to the synthetic COPROD2S2 data set and compute static factors for TE and TM modes. We propose an image based on depth averages of conductivity along with a nonlinear resolution-variance analysis of the image as the final interpretation of the data. The procedure is also applied to the well-known COPROD2 field data set.

scholarly journals A Broadband Polarization-Insensitive Graphene Modulator Based on Dual Built-in Orthogonal Slots Plasmonic Waveguide

2021 ◽  
Vol 11 (4) ◽  
pp. 1897
Author(s):  
Wei Chen ◽  
Yan Xu ◽  
Yang Gao ◽  
Lanjing Ji ◽  
Xibin Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Transverse Electric ◽  
Modulation Depth ◽  
Transverse Magnetic ◽  
Plasmonic Effect ◽  
Te Mode ◽  
Tm Mode ◽  
Electro Optic ◽  
Polarization Insensitive ◽  
Electro Optic Modulator

A broadband polarization-insensitive graphene modulator has been proposed. The dual built-in orthogonal slots waveguide allows polarization independence for the transverse electric (TE) mode and the transverse magnetic (TM) mode. Due to the introduction of metal slots in both the vertical and horizontal directions, the optical field as well as the electro-absorption of graphene are enhanced by the plasmonic effect. The proposed electro-optic modulator shows a modulation depth of 0.474 and 0.462 dB/μm for two supported modes, respectively. An ultra-low effective index difference of 0.001 can be achieved within the wavelength range from 1100 to 1900 nm. The 3 dB-bandwidth is estimated to be 101 GHz. The power consumption is 271 fJ/bit at a modulation length of 20 μm. The proposed modulator provides high speed broadband solutions in microwave photonic systems.

scholarly journals Modelling of Terrain Effect from the Magnetotelluric (MT) Field Data

2019 ◽  
Vol 9 (2) ◽  
pp. 5059-5062
Keyword(s):  
Finite Difference ◽  
Rayleigh Scattering ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Impedance Tensor ◽  
Topographic Features ◽  
Te Mode ◽  
Tm Mode ◽  
Terrain Effect ◽  
Computation Algorithm

Magnetotelluric (MT) data were recorded over highly undulating terrain in Himalayan region from Roorkee to Gangotri section in period 0.001-1000 second. In the presence of topographic distortion the interpretation may become misleading. A simple scheme based on finite difference method for the simulation of the topographic distortion in magnetotelluric response is presented. The finite difference based, forward response computation algorithm, has been extended for undulating topography. The distortion coefficients, representing the topographic effect, are designed for correcting the observed distorted impedance tensor recorded in the vicinity of topographic features. The accuracy of the scheme is checked by comparing the computed responses with the finite element, Rayleigh scattering and transmission surface results for transverse electric (TE-mode) and transverse magnetic (TM-mode) responses. The modified algorithm is used to model the terrain effect on MT data recorded from Himalayan terrain.

scholarly journals 10 nm SiO2 TM Slot Mode in Laterally Mismatched Asymmetric Fin-Waveguides

2021 ◽  
Vol 9 ◽  
Author(s):  
James Byers ◽  
Kapil Debnath ◽  
Hideo Arimoto ◽  
Muhammad K. Husain ◽  
Moïse Sotto ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Mode Conversion ◽  
Transverse Magnetic ◽  
Silicon On Insulator ◽  
Si Photonics ◽  
Te Mode ◽  
Tm Mode ◽  
Transmission Data ◽  
Fdtd Simulations ◽  
Difference Time

In this paper we demonstrate that by breaking the left/right symmetry in a bi-planar double-silicon on insulator (SOI) photonic crystal (PhC) fin-waveguide, we can couple the conventionally used transverse-electric (TE) polarized mode to the transverse-magnetic (TM) polarization slot-mode. Finite difference time domain (FDTD) simulations indicate that the TE mode couples to the robust TM mode inside the Brillouin zone. Broadband transmission data shows propagation identified with horizontal-slot TM mode within the TE bandgap for fully mismatched fabricated devices. This simultaneously demonstrates TE to TM mode conversion, and the narrowest Si photonics SiO2 slot-mode propagation reported in the literature (10 nm wide slot), which both have many potential telecommunication applications.

scholarly journals Silicon Waveguide Optical Isolator with Directly Bonded Magneto-Optical Garnet

2019 ◽  
Vol 9 (3) ◽  
pp. 609 ◽  
Author(s):  
Yuya Shoji ◽  
Tetsuya Mizumoto
Keyword(s):  
Phase Shift ◽  
Transverse Electric ◽  
Core Layer ◽  
Transverse Magnetic ◽  
Silicon Waveguide ◽  
Optical Isolation ◽  
Tm Mode ◽  
Mode Converters ◽  
Optical Isolators ◽  
Thin Interlayer

Silicon waveguide optical isolators were fabricated by direct bonding of magneto-optical (MO) garnet. The technique allowed efficient MO phase shift owing to the use of single-crystalline garnet and negligibly thin interlayer on the silicon core layer. A Mach–Zehnder interferometer (MZI) provided optical isolation utilizing the MO phase shift. High isolation, wide bandwidth, and temperature-insensitive operations had been demonstrated by tailoring the MZI design. Also, transverse electric (TE)–transverse magnetic (TM) mode converters were integrated to control operating polarization. In this paper, we reviewed these progresses on silicon waveguide optical isolators.

On the inversion and phase recovery of scattered electromagnetic amplitude data

1989 ◽  
Vol 426 (1871) ◽  
pp. 361-375 ◽  
Keyword(s):  
Electromagnetic Scattering ◽  
Transverse Electric ◽  
Complex Structure ◽  
Polarization State ◽  
Scattering Problem ◽  
Transverse Magnetic ◽  
One Dimensional ◽  
Amplitude Data ◽  
Transverse Magnetic Polarization ◽  
The One

The one-dimensional inverse electromagnetic scattering problem for the inversion of amplitude data of either linear polarization state is investigated. The method exploits the complex structure of the field scattered from a class of inhomogeneous dielectrics and enables the analytic signal to be reconstructed from measurements of the amplitude alone. The method is demonstrated and exemplified with experimental data in both transverse electric and transverse magnetic polarization states. The implications of the method as a means for regularization of scattered data are briefly discussed.

V.—Bifurcation of a Parallel-Plate Waveguide by a Unidirectionally Conducting Screen

1965 ◽  
Vol 67 (1) ◽  
pp. 50-68
Author(s):  
R. K. Arora
Keyword(s):  
Slow Wave ◽  
Parallel Plate ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Hybrid Wave ◽  
Parallel Plate Waveguide ◽  
Hopf Method ◽  
Conducting Screen ◽  
Electric Mode ◽  
Transverse Electric Mode

SynopsisThe types of modes which may exist in an infinite parallel-plate waveguide with a centrally-placed unidirectionally conducting screen are studied. The effect of bifurcating an infinite parallel-plate waveguide by such a screen in the region x>O is investigated when a transverse electric mode is incident on the bifurcated region. The problem is solved by the Wiener-Hopf method, and expressions are derived for the amplitudes and phases of the reflected and transmitted modes. It is found that the transmitted field contains a hybrid wave and a slow wave, and the reflected field contains transverse electric and transverse magnetic waves.

scholarly journals Terahertz two-cylinder waveguide coupler for transverse-magnetic and transverse-electric mode operation

2011 ◽  
Vol 98 (7) ◽  
pp. 071108 ◽  
Author(s):  
M. Theuer ◽  
A. J. Shutler ◽  
S. Sree Harsha ◽  
R. Beigang ◽  
D. Grischkowsky
Keyword(s):  
Transverse Electric ◽  
Transverse Magnetic ◽  
Waveguide Coupler ◽  
Mode Operation ◽  
Electric Mode ◽  
Transverse Electric Mode

Wideband Microstrip Patch Antennas with Transverse Electric Modes

2020 ◽  
Vol 35 (8) ◽  
pp. 971-974
Author(s):  
Tanzeela Mitha ◽  
Maria Pour
Keyword(s):  
Transverse Electric ◽  
Ground Plane ◽  
Transverse Magnetic ◽  
Impedance Bandwidth ◽  
Patch Antennas ◽  
Microstrip Patch Antennas ◽  
Microstrip Patch ◽  
Te Mode ◽  
Artificial Magnetic Conductors ◽  
Unit Cells

A wideband microstrip patch antenna, exciting the fundamental transverse electric (TE) mode, is investigated. The excitation of the TE mode is facilitated through replacing both of the patch and ground plane of a conventional microstrip antenna with artificial magnetic conductors (AMC), consisting of unipolar compact photonic bandgap (UC-PBG) unit cells. The AMC patch and the ground plane of this antenna behave as magnetic conductors within the bandgap region of the unit cells. Similar to conventional patch antennas, it is shown that by cutting a U-shaped slot in the AMC patch, wideband characteristics are realized. The antenna shows a 40% impedance bandwidth and operates at the TE10 mode. Moreover, the width of the patch is 1.75 times smaller than its length, reducing the overall size of the antenna by about 60%, compared with the conventional U-slot PEC antenna supporting the transverse magnetic (TM) mode.

scholarly journals A newly distinguished marine magnetotelluric coast effect sensitive to the lithosphere–asthenosphere boundary

2019 ◽  
Vol 218 (2) ◽  
pp. 978-987 ◽  
Author(s):  
Shunguo Wang ◽  
Steven Constable ◽  
Valeria Reyes-Ortega ◽  
Catherine A Rychert
Keyword(s):  
Electric Current ◽  
Transverse Magnetic ◽  
Hydrocarbon Exploration ◽  
Data Sets ◽  
Middle Atlantic ◽  
Ocean Ridges ◽  
Tm Mode ◽  
Coast Effect ◽  
Ocean Study ◽  
The Subject

SUMMARY The marine magnetotelluric (MT) method is a useful tool for offshore studies aimed at, for example, hydrocarbon exploration and the understanding of Earth's tectonics. Marine MT data are often distorted by coastlines because of the strong resistivity contrast between the conductive ocean and the resistive land. At mid ocean ridges, the resistivity of Earth's structure can be assumed to be two-dimensional, which allows MT data to be decomposed into a transverse electrical (TE) mode, with electric current flowing approximately along the ridge, and a transverse magnetic (TM) mode, with electric current flowing perpendicular to the ridge. We collected marine MT data at the middle Atlantic Ridge which exhibited highly negative TM-mode phases, as large as –180°, at relatively high frequencies (0.1–0.01 Hz). Similar negative phases have been observed in other marine MT data sets, but have not been the subject of study. We show here that these negative phases are caused by a newly distinguished coast effect. The TM-mode coast effect is not only a galvanic effect, as previously understood, but also includes inductive distortions. TM-mode negative phases are caused by the turning of the Poynting vector, the phase change of electromagnetic fields, and vertically flowing currents in the seafloor. The findings provide a new understanding of the TM-mode coast effect, which can guide our ability to fit the field data with the inclusion of coastlines, and reduce misinterpretation of the data in offshore studies. The study also shows that the TM-mode coast effect is sensitive to the depth and conductivity of the asthenosphere, an important feature of the Earth's interior that was the object of our Atlantic Ocean study.

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