Power and efficiency enhancement of THz radiation in a plasma by dark hollow laser beams: Effects of magnetic field

2020 ◽  
Vol 37 ◽  
pp. 100886
Author(s):  
Farhad Bakhtiari ◽  
Mahdi Esmaeilzadeh
Keyword(s):  
Magnetic Field ◽  
Laser Beams ◽  
Thz Radiation ◽  
Efficiency Enhancement

scholarly journals Generation of terahertz radiation by beating of two laser beams in collisional magnetized plasma

2016 ◽  
Vol 34 (4) ◽  
pp. 569-575 ◽  
Author(s):  
A. Hematizadeh ◽  
S.M. Jazayeri ◽  
B. Ghafary
Keyword(s):  
Magnetic Field ◽  
Magnetized Plasma ◽  
Laser Beams ◽  
Thz Radiation ◽  
Plasma Parameters ◽  
Circularly Polarized ◽  
Left Hand ◽  
Polarized Waves ◽  
Radiation Generation ◽  
The Magnetic Field

AbstractThis paper presents analytical calculations for terahertz (THz) radiation by beating of two cosh-Gaussian laser beams in a density rippled collisional magnetized plasma. Lasers beams exert a ponderomotive force on the electrons of plasma in beating frequency which generates THz waves. The magnetic field was considered parallel to the direction of lasers which leads to propagate right-hand circularly polarized or left-hand circularly polarized waves in the plasma depending on the phase matching conditions. Effects of collision frequency, decentered parameter of lasers and the magnetic field strength are analyzed for THz radiation generation. By the optimization of laser and plasma parameters, the efficiency of order 27% can be achieved.

scholarly journals Generation of terahertz radiation from beating of two intense cosh-Gaussian laser beams in magnetized plasma

2019 ◽  
Vol 37 (4) ◽  
pp. 415-427
Author(s):  
Gunjan Purohit ◽  
Vinod Rawat ◽  
Priyanka Rawat
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Beat Frequency ◽  
Magnetized Plasma ◽  
Laser Beams ◽  
Thz Radiation ◽  
Highly Sensitive ◽  
Oscillatory Velocity ◽  
Radiation Generation ◽  
Paraxial Ray

AbstractAn analytical and numerical study has been carried out for the generation of terahertz (THz) radiation by beating of two intense cosh-Gaussian laser beams (decentered Gaussian beams) in the rippled density magnetized plasma under the relativistic–ponderomotive regime. In this process, both laser beams exert a relativistic–ponderomotive force on plasma electrons at the beat frequency and impart them an oscillatory velocity in the presence of a static magnetic field. Due to coupling between this nonlinear oscillatory velocity with density ripple, nonlinear current is generated that excites the THz radiation at the different frequency. Higher-order paraxial-ray approximation (non-paraxial theory) has been used in this study. The effects of the decentered parameter, magnetic field, and density ripple on the THz radiation generation in ripple density magnetized plasma have been investigated. Further, the effect of beating of laser beams on the THz field amplitude and the efficiency of THz radiation have been studied. The amplitude and efficiency of the emitted radiation are found to be highly sensitive to the decentered parameter, magnetic field, and density ripple. It has been found that the amplitude and efficiency of the generated THz radiation increase significantly with increasing the values of decentered parameter, magnetic field, and density ripple.

scholarly journals Strong terahertz radiation generation by cosh-Gaussian laser beams in axially magnetized collisional plasma under non-relativistic ponderomotive regime

2018 ◽  
Vol 36 (2) ◽  
pp. 236-245 ◽  
Author(s):  
Prateek Varshney ◽  
Ajit Upadhayay ◽  
K. Madhubabu ◽  
Vivek Sajal ◽  
J. A. Chakera
Keyword(s):  
Magnetic Field ◽  
Ponderomotive Force ◽  
Beat Frequency ◽  
Magnetized Plasma ◽  
Laser Beams ◽  
Thz Radiation ◽  
Thz Wave ◽  
Oscillatory Velocity ◽  
Non Linear ◽  
Radiation Generation

AbstractWe propose a scheme for terahertz (THz) radiation generation by non-linear mixing of two cosh-Gaussian laser beams in axially magnetized plasma with spatially periodic density ripple where electron-neutral collisions have been taken into account. The laser beams exert a non-linear ponderomotive force due to spatial non-uniformity in the intensity. The plasma electrons acquire non-linear oscillatory velocity under the influence of ponderomotive force. This oscillatory velocity couples with preformed density ripples (n′ = n0αeiαz) to generate a strong transient non-linear current that resonantly derives THz radiation of frequency ~ωh (upper hybrid frequency). Laser frequencies (ω1 and ω2) are chosen such that the beat frequency (ω) lies in the THz region. The periodicity of density ripple provides phase-matching conditions (ω = ω1 − ω2 and $\vec k = \vec k_1 - \vec k_2 + {\rm \vec \alpha} $) to transfer maximum momentum from laser to THz radiation. The axially applied external magnetic field can be utilized to enhance the non-linear coupling and control various parameters of generated THz wave. The effects of decentered parameters (b), collisional frequency (νen), and magnetic field strength (B0 = ωcm/e) are analyzed for strong THz radiation generation. Analytical results show that the amplitude of THz wave enhances with decentered parameters as well as with the magnitude of axially applied magnetic field. The THz amplitude is found to be highly sensitive to collision frequency.

THz-radiation Generation from an Intracavity Saturable Bragg Reflector in a Magnetic Field

1998 ◽  
Vol 37 (Part 2, No. 2A) ◽  
pp. L125-L126 ◽  
Author(s):  
Nobuhiko Sarukura ◽  
Hideyuki Ohtake ◽  
Zhenlin Liu ◽  
Taro Itatani ◽  
Takeyoshi Sugaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bragg Reflector ◽  
Thz Radiation ◽  
Radiation Generation

scholarly journals Three-Dimensional Skyrmions with Arbitrary Topological Number in a Ferromagnetic Spin-1 Bose-Einstein Condensate

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Huan-Bo Luo ◽  
Lu Li ◽  
Wu-Ming Liu
Keyword(s):  
Magnetic Field ◽  
Vortex Ring ◽  
Three Dimensional ◽  
Einstein Condensate ◽  
Laser Beams ◽  
Quantization Axis ◽  
Density Distributions ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Topological Number

AbstractWe propose a new scheme for creating three-dimensional Skyrmions in a ferromagnetic spin-1 Bose-Einstein condensate by manipulating a multipole magnetic field and a pair of counter-propagating laser beams. The result shows that a three-dimensional Skyrmion with topological number Q = 2 can be created by a sextupole magnetic field and the laser beams. Meanwhile, the vortex ring and knot structure in the Skyrmion are found. The topological number can be calculated analytically in our model, which implies that the method can be extended to create Skyrmions with arbitrary topological number. As the examples, three-dimensional Skyrmions with Q = 3, 4 are also demonstrated and are distinguishable by the density distributions with a specific quantization axis. These topological objects have the potential to be realized in ferromagnetic spin-1 Bose-Einstein condensates experimentally.

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