Magnetically tuned THz radiation through the HA-HA-CNTs under the effect of a transverse electric field.

Autor: Kumar, Sandeep, Kant, Niti, Thakur, Vishal
Zdroj: Indian Journal of Physics; Mar2024, Vol. 98 Issue 3, p1139-1145, 7p
Abstrakt: In the present theoretical analysis, we have demonstrated the magnetically tuned terahertz (THz) wave generation through the structure of hollow anharmonic horizontally aligned carbon nanotubes (HA-HA-CNTs) grown and embedded over the dielectric substrate under the effect of an externally applied transverse static electric field. Two transversely co-propagating amplitude-modulated (AM) filamented laser beams interact with this structure of HA-HA-CNTs under the combined effect of the externally applied static electric and magnetic fields, acting mutually perpendicular to each other as well as to the direction of propagation of the AM filamented laser beams. The novelty in our scheme is the use of non-uniform distribution of electrons in CNTs, whereas most of the research workers have chosen a uniform distribution of electrons in CNTs. Due to this, the restoration force experienced by the electrons of CNTs is not the same, but it becomes different for every electron of CNTs, and this results in anharmonicity. This anharmonicity in CNTs helps to broaden the resonance peak. The laser beams also exert the static and beat frequency nonlinear ponderomotive forces on the electrons of HA-HA-CNTs in such a way that the static nonlinear ponderomotive force is balanced by the pressure gradient force to form a transverse density ripple of zero frequency, whereas beat frequency nonlinear ponderomotive force is responsible for the THz generation through the HA-HA-CNTs. Nonlinear coupling between the drift velocity of the electrons and the density of electrons present in the plasma structure of HA-HA-CNTs results in the enhancement of THz generation. We have also found that the normalized THz field amplitude obtained at the resonance frequency point shows a significant enhancement with the increase of externally applied electric field in the steps of 5 kV cm - 1 starting from 5 to 15 kV cm - 1 , and magnetic field in the steps of 5 kG starting from 10 to 20 kG. The emitted THz radiations can be proved useful to detect bacterial and cell hydration states in the medical diagnosis. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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