Two-color two-dimensional terahertz spectroscopy: A new approach for exploring even-order nonlinearities in the nonperturbative regime

Michael Woerner; Ahmed Ghalgaoui; Klaus Reimann; Thomas Elsaesser

doi:10.1063/5.0047700

Terahertz characterization of two-dimensional low-conductive layers enabled by metal gratings

Scientific Reports ◽

10.1038/s41598-021-82560-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Prashanth Gopalan ◽

Yunshan Wang ◽

Berardi Sensale-Rodriguez

Keyword(s):

Optical Transmission ◽

Terahertz Spectroscopy ◽

Design Guidelines ◽

Two Dimensional ◽

Highly Sensitive ◽

Transmission Measurements ◽

Metal Gratings ◽

Low Sensitivity ◽

Non Destructive

AbstractWhile terahertz spectroscopy can provide valuable information regarding the charge transport properties in semiconductors, its application for the characterization of low-conductive two-dimensional layers, i.e., σs < < 1 mS, remains elusive. This is primarily due to the low sensitivity of direct transmission measurements to such small sheet conductivity levels. In this work, we discuss harnessing the extraordinary optical transmission through gratings consisting of metallic stripes to characterize such low-conductive two-dimensional layers. We analyze the geometric tradeoffs in these structures and provide physical insights, ultimately leading to general design guidelines for experiments enabling non-contact, non-destructive, highly sensitive characterization of such layers.

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Two-dimensional asynchronous spectrum with auxiliary cross peaks in probing intermolecular interactions

RSC Advances ◽

10.1039/c5ra16062f ◽

2015 ◽

Vol 5 (107) ◽

pp. 87739-87749 ◽

Cited By ~ 20

Author(s):

Xiaopei Li ◽

Anqi He ◽

Kun Huang ◽

Huizhou Liu ◽

Ying Zhao ◽

...

Keyword(s):

Intermolecular Interaction ◽

Intermolecular Interactions ◽

Two Dimensional ◽

New Approach

A new approach called “asynchronous spectrum with auxiliary peaks (ASAP)” is proposed for generating a 2D asynchronous spectrum to investigate the intermolecular interaction between two solutes (P and Q) dissolved in the same solution.

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A new approach for representing and recognition of two-dimensional objects

[1990] Proceedings of the 2nd International IEEE Conference on Tools for Artificial Intelligence ◽

10.1109/tai.1990.130400 ◽

2002 ◽

Author(s):

D.C.D. Hung ◽

B.C. Cheng

Keyword(s):

Two Dimensional ◽

New Approach

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Half division two-dimensional method for simple sinusoidal quantities parameters accurate measurement

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2021-4-16-21 ◽

2021 ◽

pp. 16-21

Author(s):

Kirill Yu. Solomentsev ◽

Vyacheslav I. Lachin ◽

Aleksandr E. Pasenchuk

Keyword(s):

Measuring Instruments ◽

Measured Signal ◽

Two Dimensional ◽

Measuring Device ◽

New Approach ◽

Precision Measuring ◽

Useful Signal ◽

Midpoint Method ◽

Order Of Magnitude ◽

Current Measuring

Several variants of half division two-dimensional method are proposed, which is the basis of a fundamentally new approach for constructing measuring instruments for sinusoidal or periodic electrical quantities. These measuring instruments are used in the diagnosis of electric power facilities. The most general variant, called midpoint method, is considered. The proposed midpoint method allows you to measure much smaller than using widespread methods, alternating currents or voltages, especially when changing the amplitude of the measured signal in very wide ranges, by 1–2 orders of magnitude. It is shown that using the midpoint method it is possible to suppress sinusoidal or periodic interference in the measuring path, in particular, to measure small alternating current when sinusoidal or periodic interference is 1–2 orders of magnitude higher than the useful signal. Based on the results of comparative tests, it was found that the current measuring device implementing the midpoint method is an order of magnitude more sensitive than the currently used high-precision measuring instruments.

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Исследование параметров двумерного электронного газа в квантовых ямах InGaN/GaN методом терагерцового плазмонного резонанса

Физика и техника полупроводников ◽

10.21883/ftp.2021.11.51561.9685 ◽

2021 ◽

Vol 55 (11) ◽

pp. 1059

Author(s):

Е.Р. Бурмистров ◽

Л.П. Авакянц

Keyword(s):

Quantum Wells ◽

Terahertz Spectroscopy ◽

Radiation Power ◽

Electron Gas ◽

Femtosecond Laser Pulses ◽

Two Dimensional ◽

Dimensional Electron ◽

Two Dimensional Electron Gas ◽

Plasmon Resonances ◽

Dimensional Electron Gas

A new approach to determining the parameters of a two-dimensional electron gas in InGaN/GaN quantum wells is proposed. It is based on the method of terahertz spectroscopy with time resolution, within the framework of which the terahertz frequencies of two-dimensional plasmon resonances excited in the studied samples of InGaN/AlGaN/GaN heterostructures by femtosecond laser pulses at a wavelength of 797 nm were recorded. Oscillating behavior of the output terahertz radiation power with minima in the frequency range 1−5 THz is shown, which is associated with the excitation of plasmon oscillations in a two-dimensional electron gas localized in an InGaN/GaN quantum well. During the processing of terahertz spectra, the effect of renormalization of the effective mass of two-dimensional electron gas, as well as phase modulation near the frequencies of plasmon resonances with an increase in the temperature of the sample from 90 to 170 K, was found. The proposed method is non-contact and can be used in a wide temperature range.

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New approach to finite frequency Filter Design for two-dimensional T-S fuzzy systems

E3S Web of Conferences ◽

10.1051/e3sconf/202129701036 ◽

2021 ◽

Vol 297 ◽

pp. 01036

Author(s):

Ben Meziane Khaddouj ◽

Abderrahim El-Amrani ◽

Ismail Boumhidi

Keyword(s):

Fuzzy Systems ◽

Filter Design ◽

Asymptotically Stable ◽

Two Dimensional ◽

Finite Frequency ◽

New Approach ◽

Filter Model ◽

Error System ◽

Non Linear Systems ◽

Takagi Sugeno

This paper considers the problem of filter design for two-dimensional (2D) discrete-time non-linear systems in Takagi-Sugeno (T-S) fuzzy mode. The problem to be solved in the paper is to find a H∞ filter model such that the filtering error system is asymptotically stable. A numerical example is employed to illustrate the validity of the proposed methods.

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Quasi-two-dimensional approximation for numerical simulation of flows in engine ducts

Progress in Propulsion Physics – Volume 11 ◽

10.1051/eucass/201911657 ◽

2019 ◽

Cited By ~ 1

Author(s):

V. Vlasenko ◽

A. Shiryaeva

Keyword(s):

High Speed ◽

Fuel Injection ◽

Three Dimensional ◽

Preliminary Design ◽

Two Dimensional ◽

Combustion Chambers ◽

New Approach ◽

One Dimensional ◽

Dimensional Approximation ◽

3D Flows

New quasi-two-dimensional (2.5D) approach to description of three-dimensional (3D) flows in ducts is proposed. It generalizes quasi-one-dimensional (quasi-1D, 1.5D) theories. Calculations are performed in the (x; y) plane, but variable width of duct in the z direction is taken into account. Derivation of 2.5D approximation equations is given. Tests for verification of 2.5D calculations are proposed. Parametrical 2.5D calculations of flow with hydrogen combustion in an elliptical combustor of a high-speed aircraft, investigated within HEXAFLY-INT international project, are described. Optimal scheme of fuel injection is found and explained. For one regime, 2.5D and 3D calculations are compared. The new approach is recommended for use during preliminary design of combustion chambers.

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