scholarly journals Strong terahertz radiation generation by beating of two x-mode spatial triangular lasers in magnetized plasma

2014 ◽  
Vol 33 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Prateek Varshney ◽  
Vivek Sajal ◽  
Sweta Baliyan ◽  
Navneet K. Sharma ◽  
Prashant K. Chauhan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Terahertz Radiation ◽  
Beam Width ◽  
Laser Pulses ◽  
Magnetized Plasma ◽  
Thz Radiation ◽  
Dc Magnetic Field ◽  
Radiation Generation ◽  
Transverse And Longitudinal Components ◽  
Frequency Laser

AbstractResonant THz radiation generation is proposed by beating of two spatial-triangular laser pulses of different frequencies (ω1, ω2) and wave numbers $\lpar \vec k_1 \comma \; \vec k_2 \rpar $ in plasma having external static magnetic field. Laser pulses co-propagating perpendicular to a dc magnetic field exert a nonlinear ponderomotive force on plasma electrons, imparting them an oscillatory velocity with finite transverse and longitudinal components. Oscillatory plasma electrons couple with periodic density ripples n′ = nq0eiqz to produce a nonlinear current, i.e., responsible for resonantly driving terahertz radiation at $\lpar {\rm \omega} = {\rm \omega} _1 - {\rm \omega} _2 \comma \; \vec k = \vec k_1 - \vec k_2 + \vec q\rpar $. Effects of THz wave frequency, laser beam width, density ripples, and applied magnetic field are studied for the efficient THz radiation generation. The frequency and amplitude of THz radiation were observed to be better tuned by varying dc magnetic field strength and parameters of density ripples (amplitude and periodicity). An efficiency about 0.02 is achieved for laser intensity of 2 × 1015 W/cm2 in a plasma having density ripples about 30%, plasma frequency about 1 THz and magnetic field about 100 kG.

scholarly journals Tunable terahertz radiation generation by nonlinear photomixing of cosh-Gaussian laser pulses in corrugated magnetized plasma

2017 ◽  
Vol 35 (2) ◽  
pp. 279-285 ◽  
Author(s):  
P. Varshney ◽  
V. Sajal ◽  
A. Upadhyay ◽  
J. A. Chakera ◽  
R. Kumar
Keyword(s):  
Magnetic Field ◽  
Beam Quality ◽  
Beam Width ◽  
Laser Pulses ◽  
Magnetized Plasma ◽  
Thz Radiation ◽  
Oscillatory Velocity ◽  
Radiation Generation ◽  
Factor Α

AbstractThis paper presents a scheme of THz generation by nonlinear photomixing of two cosh-Gaussian lasers pulses having different frequencies (ω1, ω2) and wave numbers $(\vec k_1, \vec k_2 )$ and same electrical field amplitude in a corrugated plasma embedded with transverse static magnetic field. Cosh-Gaussian laser pulses have steep gradient in intensity profile along with wider cross-section, which exerts a stronger nonlinear ponderomotive force at ω1 − ω2 and $\vec k_1 - \vec k_2 $ on plasma electrons imparting a nonlinear oscillatory velocity to plasma electrons. Oscillatory plasma electrons couple with the density ripple n′ = nα0eiαx to produce a nonlinear current, which is responsible for resonant THz radiation at frequency $\sim\left( {{\rm \omega} _{\rm c}^2 + {\rm \omega} _{\rm p}^2} \right)^{1/2} $. The amplitude, efficiency and beam quality of THz radiation can be optimized by choosing proper corrugation factor (α of the plasma), applied magnetic field (ωc), decentered parameter (b), and beam width parameter a0 of cosh-Gaussian lasers. An efficiency of $\sim\!10^{ - 2} - 10^{ - 1} $ is achieved for laser electric field E = 3.2 × 109 V/cm.

scholarly journals Enhanced terahertz radiation generation by two-color laser pulses propagating in plasma

2016 ◽  
Vol 34 (2) ◽  
pp. 378-383 ◽  
Author(s):  
N.K. Verma ◽  
P. Jha
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Numerical Model ◽  
Laser Pulses ◽  
Magnetized Plasma ◽  
Thz Radiation ◽  
Homogeneous Plasma ◽  
One Dimensional ◽  
Radiation Generation ◽  
Transverse Electromagnetic

AbstractA one-dimensional (1D) numerical model for studying enhanced terahertz (THz) radiation generation by mixing of ordinary and extraordinary modes of two-color laser pulses propagating in magnetized plasma has been presented. The direction of the static external magnetic field is such that one of the two laser pulses propagates in the extraordinary mode, while the other pulse propagates in the ordinary mode, through homogeneous plasma. A transverse electromagnetic wave with frequency in the THz range is generated due to the presence of the external magnetic field. It is observed that larger amplitude THz radiation can be generated by mixing of the ordinary and extraordinary modes of the two-color laser pulses as compared with the single laser pulse propagating in the extraordinary mode. Further, 2D simulations using the XOOPIC code show that the fields obtained via simulation study are compatible with those obtained from the numerical model.

scholarly journals Strong terahertz radiation generation by beating of extra-ordinary mode lasers in a rippled density magnetized plasma

2013 ◽  
Vol 31 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Prateek Varshney ◽  
Vivek Sajal ◽  
K.P. Singh ◽  
Ravindra Kumar ◽  
Navneet K. Sharma
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Terahertz Radiation ◽  
Magnetized Plasma ◽  
Wave Number ◽  
Thz Radiation ◽  
Present Scheme ◽  
Oscillatory Velocity ◽  
Radiation Generation ◽  
Ripple Amplitude

AbstractA scheme of terahertz radiation generation is proposed by beating of two extra-ordinary lasers having frequencies and wave numbers$\lpar {\rm \omega}_1\comma \; \vec k_1 \rpar $and$\lpar {\rm \omega}_2\comma \; \vec k_2 \rpar $, respectively in a magnetized plasma. Terahertz wave is resonantly excited at frequency$\lpar {\rm \omega}_1 - {\rm \omega}_2 \rpar $and wave number (k1 − k2 + q) with a wave number mismatch factorqwhich is introduced by the periodicity of plasma density ripples. In this process, the lasers exert a beat ponderomotive force on plasma electrons and impart them an oscillatory velocity with both transverse and longitudinal components in the presence of transverse static magnetic field. The oscillatory velocity couples with density ripples and produces a nonlinear current that resonantly excites the terahertz radiation. Effects of periodicity of density ripples and applied magnetic field are analyzed for strong THz radiation generation. The terahertz radiation generation efficiency is found to be directly proportional to the square of density ripple amplitude and rises with the magnetic field strength. With the optimization of these parameters, the efficiency ~10−3is achieved in the present scheme. The frequency and power of generated THz radiation can be better tuned with the help of parameters like density ripple amplitude, periodicity and applied magnetic field strength in the present scheme.

Tunable and efficient terahertz radiation generation by photomixing of two super Gaussian laser pulses in a corrugated magnetized plasma

2015 ◽  
Vol 117 (19) ◽  
pp. 193303 ◽  
Author(s):  
Prateek Varshney ◽  
Vivek Sajal ◽  
Kunwar Pal Singh ◽  
Ravindra Kumar ◽  
Navneet K. Sharma
Keyword(s):  
Terahertz Radiation ◽  
Laser Pulses ◽  
Magnetized Plasma ◽  
Radiation Generation

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.

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