Optical Guiding in 50-Meter-Scale Air Waveguides
A. Goffin, I. Larkin, A. Tartaro, Aaron Schweinsberg, Anthony Valenzuela, E. W. Rosenthal, H. M. Milchberg
Abstract
The distant projection of high-peak and average-power laser beams in the atmosphere is a long-standing goal with a wide range of applications.Our early proof-of-principle experiments [Phys.Rev. X 4, 011027 (2014)] presented one solution to this problem, employing the energy deposition of femtosecond filaments in air to sculpt millisecond-lifetime sub-meter-length air waveguides.Here, we demonstrate air waveguiding at the 50-m scale, 60 longer, making many practical applications now possible.We employ a new method for filament energy deposition: multifilamentation of Laguerre-Gaussian LG 01 "donut" modes.We first investigate the detailed physics of this scheme over a shorter 8-m in-lab propagation range corresponding to 13 Rayleigh lengths of the guided pulse.We then use these results to demonstrate optical guiding over 45 m in the hallway adjacent to the lab, corresponding to 70 Rayleigh lengths.Injection of a continuous-wave probe beam into these waveguides demonstrates very long lifetimes of tens of milliseconds.