title: Radial thermal gradients occurring in the bimodal atmospheric guided energy laser scheme: a theoretical study.
abstract: A laser propagation concept, termed bimodal atmospheric guided energy laser (BAGEL) [L. A. Newman and D. C. Smith, Appl. Phys. Lett. 38, 590 (1981)], is investigated. This propagation concept involves establishing a guiding channel using a laser beam propagating in the TEM(01) mode followed by a main beam propagating in the TEM(00) mode. The dynamics of the formation of the refractive-index profile in a gas is investigated. The focusing conditions for the near-axis portion of the channel-forming beam are obtained. It is shown that using the BAGEL concept for propagating laser energy is feasible provided that the time difference between the channel-forming and main beam is between 3 and 10 acoustic transit times, the pulse width between each pulse pair is of the order of 20 acoustic transit times, and the maximum number of pulse pairs that can be transmitted is of the order of 1000, provided that the relative intensity between the main and channel-forming beam is <0.5.
authors.affiliation: University of Maryland, Department of Electrical Engineering, College Park, Maryland 20742, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Hauser
authors.forename: C C
authors.initials: CC
authors.lastname: Davis