Propagation and Stability of Laser Pulses in the Atmosphere

Long-range propagation of laser pulses in the atmosphere is of interest in free-space communication, remote detection, and directed energy, among others. We analyze and numerically simulate the propagation and stability of laser pulses propagating in the vertical direction. Stability of the dynamic equilibrium of the laser pulse is analyzed and numerically simulated, taking into account the variation of the air density, linear and nonlinear dispersion, and turbulence level, as a function of altitude. In the dynamic equilibrium, the spot size, pulse duration, wave-front curvature, phase, and chirp evolve self-consistently along the propagation path. Significant intensity enhancement at remote distances is achieved by tailoring the laser parameters in such a way that the transverse and longitudinal focal points nearly coincide. In addition, the hybrid filamentation-modulation instability is analyzed and simulated, indicating that the beam breaks up transversely and longitudinally. Our model enables laser pulse propagation studies over distances that ordinarily would be computationally challenging.