7. Third harmonic sychronization

Author(s):  
Nikolaos I. Margaris
Keyword(s):  
2015 ◽  
Vol 9 (1) ◽  
pp. 591-599
Author(s):  
Ma Wenchuan ◽  
Zhitong Li ◽  
Chen Daochang ◽  
Qi Jiaming ◽  
Zhou Qiang ◽  
...  

For resolving the problem that power filter cannot work normally because TCR (thyristor controlled reactor) generates extra third harmonic current under asymmetrical voltage, the paper proposes the estimation method of current capacity that TCR generates extra third harmonic current under asymmetrical voltage. Considering extra third harmonic current under asymmetrical voltage, Optimum method based on genetic algorithm is used to design the parameters of power filter. With reactive power compensation and harmonic suppression project of a steel mill as example, the proposed method is simulated by Matlab. Simulation results show optimized power filter can eliminate extra third harmonic current effects under asymmetrical voltage, meet the requirement of reactive power compensation, reduce harmonics current that load injects into system, and guarantee the power filter safe operation under asymmetrical voltage.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3194
Author(s):  
Adrian Petris ◽  
Petronela Gheorghe ◽  
Tudor Braniste ◽  
Ion Tiginyanu

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.


2021 ◽  
Vol 1859 (1) ◽  
pp. 012050
Author(s):  
Z Kasapeteva ◽  
A Dakova ◽  
V Slavchev ◽  
D Dakova ◽  
L Kovachev ◽  
...  

Author(s):  
Ezequiel Ramos Rodriguez ◽  
Ramon Leyva ◽  
Qingxiang Liu ◽  
Christopher David Townsend ◽  
Glen Ghias Farivar ◽  
...  

2021 ◽  
Vol 28 (3) ◽  
pp. 032710
Author(s):  
Max Karasik ◽  
Jaechul Oh ◽  
S. P. Obenschain ◽  
A. J. Schmitt ◽  
Y. Aglitskiy ◽  
...  

2021 ◽  
Vol 7 (15) ◽  
pp. eabf9809
Author(s):  
Sergey Kovalev ◽  
Hassan A. Hafez ◽  
Klaas-Jan Tielrooij ◽  
Jan-Christoph Deinert ◽  
Igor Ilyakov ◽  
...  

Graphene is conceivably the most nonlinear optoelectronic material we know. Its nonlinear optical coefficients in the terahertz frequency range surpass those of other materials by many orders of magnitude. Here, we show that the terahertz nonlinearity of graphene, both for ultrashort single-cycle and quasi-monochromatic multicycle input terahertz signals, can be efficiently controlled using electrical gating, with gating voltages as low as a few volts. For example, optimal electrical gating enhances the power conversion efficiency in terahertz third-harmonic generation in graphene by about two orders of magnitude. Our experimental results are in quantitative agreement with a physical model of the graphene nonlinearity, describing the time-dependent thermodynamic balance maintained within the electronic population of graphene during interaction with ultrafast electric fields. Our results can serve as a basis for straightforward and accurate design of devices and applications for efficient electronic signal processing in graphene at ultrahigh frequencies.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Arindam Dasgupta ◽  
Jie Gao ◽  
Xiaodong Yang

AbstractThe mechanical exfoliation of naturally occurring layered materials has emerged as an easy and effective method for achieving ultrathin van der Waals (vdW) heterostructures with well-defined lattice orientations of the constituent two-dimensional (2D) material layers. Cylindrite is one such naturally occurring vdW heterostructure, where the superlattice is composed of alternating stacks of SnS2-like and PbS-like layers. Although the constituent 2D lattices are isotropic, inhomogeneous strain occurring from local atomic alignment for forcing the commensuration makes the cylindrite superlattice structurally anisotropic. Here, we demonstrate the highly anisotropic optical responses of cylindrite thin flakes induced by the anisotropic crystal structure, including angle-resolved polarized Raman scattering, linear dichroism, and polarization-dependent anisotropic third-harmonic generation. Our results provide a promising approach for identifying various natural vdW heterostructure-based 2D materials with tailored optical properties and can be harnessed for realizing anisotropic optical devices for on-chip photonic circuits and optical information processing.


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