Online ISSN: 2515-8260

Keywords : q-Gaussian


Gouy Phase Shift Of Q-Gaussian Laser Beams In Collisional Plasma With Density Ramp

Naveen Gupta; Sandeep Kumar

European Journal of Molecular & Clinical Medicine, 2020, Volume 7, Issue 7, Pages 3805-3810

Gouy phase shift of q-Gaussian laser beams interacting nonlinearly with collisional plasmas with axially increasing density has been investigated theoretically. The Gouy phase shift also known as phase anomaly occurs at a fundamental level from position momentum uncertainty. Due to intensity gradient over the cross section of the laser beam redistribution of the carriers occurs on account of collisional heating of the plasma. The resulting index of refraction resembles to that of graded index fibers that stimulates the laser beam to get self-focused. The reduction in transverse dimensions of the laser beam in turn leads to spread in transverse momentum of its photons. This transverse momentum spread then modifies the axial phase of the laser beam. Following variational theory, a set of coupled differential equations for the evolution of beam width and axial phase of the laser beam has been obtained. The equations so obtained have been solved numerically so see the effect of laser and plasma parameters on the evolution of beam envelope.

Virial Theory For Self Action Effects Of Laser Beams In Preformed Plasma Channels

Naveen Gupta; Sandeep Kumar; Rajendersingh .

European Journal of Molecular & Clinical Medicine, 2020, Volume 7, Issue 7, Pages 3811-3824

Self action effects of intense laser beams interacting nonlinearly with pre- formed parabolic plasma channels have been investigated theoretically. Particularly the phenomena of self focusing, self channeling and self phase modulation of the laser beam arising as a consequence of the optical nonlinearity of the plasma channel have been investigated. Due to nonuniform irradiance over the laser beam, the ponderomotive force becomes active that alters the spatial density profile of the channel. As the index of refraction of the plasma depends on electron concentration, there is a resultant modification of the index of refraction of the channel in the presence of laser beam. This modification in the optical response of the plasma channel in turn alters the propagation dynamics of the beam envelope. Following Virial theory, a semi analytical solution of the wave equation for beam envelope has been obtained. Emphases are put on investigation of beam with and axial phase of the laser beam.