Analyzing and simulate the near-mid field propagation for a Gaussian beam of x-ray laser.

Gaussian beam propagation of the Free Electron Laser (FEL) through the atmosphere is a very important topic for many vital applications in the military, scientific, and medical fields, where laser beam spot size and final power are extremely important requirements in most laser applications. The propagation of a Gaussian laser beam in the atmosphere is subject to attenuation processes that affect the laser beam. From the results, simulations of the free electron laser system showed that an X-ray laser with a wavelength of 0.50418 nm can be produced with an energy beam of 200 PJ. The M2 quality factor will increase with the propagation distance, determining the final laser spot size. As a result of the attenuation processes, there is a slight loss in the final energy of the laser as well as divergence in the laser beam that reaches the target. The amount of attenuation is highly dependent on the density of the atmosphere and the size of the laser spot. When the laser beam propagates in the near-field (less than 20 m) or mid-field (20–100 m) horizontally and vertically at sea level, the values of the attenuation coefficient when propagating in the horizontal direction are greater compared to the propagation in the vertical direction. [ABSTRACT FROM AUTHOR]