Propagation Characteristics of Higher-Order Hollow Sinh-Gaussian Laser Beams in Collisionless Plasma

Hollow sinh-Gaussian (HshG) beams are the appropriate analogue to describe optical beams with null central intensity. In the present work, the modified paraxial approach is adopted to study the propagation characteristics of higher-order HshG beams in plasma. The nonlinearity in the dielectric constant of plasma considered herein is of the ponderomotive type. A nonlinear differential equation is obtained for the beam-width parameter and then solved numerically to investigate the self-focusing/defocusing characteristics of HshG beams in plasma. The dependence of the beam-width parameter of HshG beams on the dimensionless distance of propagation through plasma has been specifically carried out. Results show that the self-focusing ability of the aforesaid beams weakens with an increase in the order of HshG beams. The effect of the initial intensity parameter and the normalized plasma frequency for higher-order HshG beams has also been examined.