Resonant excitation of THz radiations by the interaction of amplitude-modulated laser beams with an anharmonic CNTs in the presence of static D.C. electric and magnetic fields

Kumar, Sandeep; Vij, Shivani; Kant, Niti; Thakur, Vishal

doi:10.1016/j.cjph.2022.06.004

Cited by 28 publications

(7 citation statements)

References 38 publications

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“…´-( ) 5.9 10 . 5 However, in the present model of THz generation, we have obtained the maximum value of normalized THz ( ) 1.17 by using the optimized values of static electric and magnetic fields / ( ) 15kV cmand125kG which is better than the Bhasin et al [22]. It is evident that at = / E 5 kV cm, dc THz amplitude increases by 1.25% as compared to the THz amplitude in the absence of the D.C. electric field and attains peak value at 15 kV cm −1 .…”

Section: Numerical and Graphical Analysismentioning

confidence: 99%

“…Over the last two decades, the terahertz (THz) generation has become one of the most active research fields because of its potential applications in remote sensing [1], explosive detection [2], material imaging [3], and many more. From the view of efficient THz generation, several researchers have already proposed different mechanisms and schemes such as by applying magnetic fields on the array of carbon nanotubes (CNTs) [4][5][6][7], by nonlinear mixing of lasers [8], by using filamented laser beams [9][10][11], by using self-focusing and cross-focusing of laser beams [12,13], etc The mechanisms involving laser interaction with CNTs are of great interest because of more efficiency. The CNTs have extraordinary thermal and electrical conductivity with the advantage of compact size, which makes these nanotubes effective and efficient THz sources.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of spatial-Gaussian lasers with the magnetized CNTs in the presence of DC electric field and enhanced THz emission

et al. 2022

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The interaction of spatial-Gaussian lasers (〖~10〗^13 Wcm^(-2) ) with magnetized carbon nanotubes (CNTs) in the presence of a D.C. electric field is shown to broaden the surface plasmon resonance effectively. The prime feature of the interaction of lasers with magnetized CNTs is that when the electron cylinder of CNT is shifted with respect to the ion cylinder, the space charge electric field is developed in the overlapped region and results in the restoration force of the electrons. The restoration force along with the ponderomotive and magnetic forces assist to increase the nonlinear current which is further enhanced by the drift velocity acquired by the electrons of CNTs due to the applied static electric field. This action is also responsible for the enhanced THz yield at surface plasmon resonance condition ω=ω_P √(ρ⁄(2ϵ_g )+((ω_c^2)⁄(ω_P^2 ))), where ρ is the polarization coefficient, ϵ_g is the relative permittivity of the dielectric substrate, ω_c is the cyclotron frequency of CNT electrons and ω_p is the plasma frequency. The study reveals that THz generation from the magnetized CNTs may be a promising source for the detection of dangerous chemicals like royal demolition explosive (RDX), pentaerythritol tetra-nitrate (PETN), trinitrotoluene (TNT), etc.

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Section: Numerical and Graphical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interaction of spatial-Gaussian lasers with the magnetized CNTs in the presence of DC electric field and enhanced THz emission

et al. 2022

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“…For efficient THz generation, the research workers formulated various schemes. The researchers preferred the CNTs under the influence of an external magnetic field to generate efficient THz radiation [6][7][8][9]. This is because of some special features of CNTs like high thermal and electrical conductivity with nano dimensions.…”

Section: Introductionmentioning

confidence: 99%

THz Field Enhancement under the Influence of Cross-focused Laser Beams in the m-CNTs

Thakur

Kant²,

Kumar³

2023

Trends Sci

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In the present analysis, we have studied the effect of cross-focused Gaussian laser beams propagating through the array of magnetized carbon nanotubes (m-CNTs) to enhance the terahertz (THz) field amplitude of emitted radiation. The plasma present in the form of CNTs rearranges itself due to the ponderomotive nonlinearity, which gives rise to the nonlinear optical phenomenon known as the cross-focusing of laser beams. The ponderomotive nonlinearity, cross-focusing of lasers, and anharmonic behavior of m-CNTs are responsible for the very strong nonlinear current density in the system. The cross-focusing effect of the propagating Gaussian laser beams increases with the increase in the externally applied static magnetic field, which is applied along the longitudinal axis of the CNTs. As a result, the normalized THz field amplitude shows a significant enhancement, and the THz radiations emitted in this way can be utilized in biological diagnosis (of the living beings) instead of X-rays. The internal and external diameters of the CNTs also make a notable impact on the THz field amplitude. HIGHLIGHTS We have studied the effect of cross-focused laser beams propagating through the magnetized carbon nanotubes to enhance the terahertz field of emitted radiation The ponderomotive nonlinearity, cross-focusing of lasers, and anharmonic behavior are responsible for the strong nonlinear current density in the system The internal and external diameters of the m- CNTs also make a notable impact on the THz field amplitude The frequency of emitted radiation shows that these can be utilized in the biological diagnosis of living beings instead of X-rays GRAPHICAL ABSTRACT

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“…Terahertz generation using terawatt-level lasers was first proposed and exhibited by Hamster et al (1993). Some methods to produce terahertz radiations involve using nonlinear crystals by optical rectification (Singh et al 2017), photo-conduction processes (Cai et al 1997) and by coupling of lasers with anharmonic carbon nanotubes (CNTs) (Kumar et al 2022 a , b , 2023). Using nonlinear crystals, it has been possible to go up to a laser intensity of the order of .…”

Section: Introductionmentioning

confidence: 99%

Generation of terahertz radiation by a Hermite–Gaussian laser beam inside magnetoplasma with a density ramp

2023

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In the present scheme of work, the Hermite–Gaussian (HG) laser beam dynamics has been investigated under the influence of an upward density ramp inside magnetized plasma, where both relativistic and ponderomotive nonlinearities are operative. One can achieve self-focusing of laser beam due to the change in the medium's dielectric function, which comes into operation due to the expulsion of plasma electrons from the high intensity to the low-intensity region by ponderomotive force and their motion at relativistic speeds. The dynamics of the laser beam and terahertz generation have been investigated by using the moment theory approach. It has been observed from the present analysis that the dynamics of the laser beam and the production of terahertz radiations strongly depends upon the HG laser beam and plasma parameters. In addition to this, the effect of density ramp and magnetic field has also been investigated on the efficiency of terahertz generation. It has been observed that higher-order modes of the HG laser beam play a dominant role in the production of terahertz radiations.

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Resonant excitation of THz radiations by the interaction of amplitude-modulated laser beams with an anharmonic CNTs in the presence of static D.C. electric and magnetic fields

Cited by 28 publications

References 38 publications

Interaction of spatial-Gaussian lasers with the magnetized CNTs in the presence of DC electric field and enhanced THz emission

Interaction of spatial-Gaussian lasers with the magnetized CNTs in the presence of DC electric field and enhanced THz emission

THz Field Enhancement under the Influence of Cross-focused Laser Beams in the m-CNTs

Generation of terahertz radiation by a Hermite–Gaussian laser beam inside magnetoplasma with a density ramp

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