Circular arrays of plasma filaments induced by femtosecond laser pulses in atmospheric air are shown to support guided modes of electromagnetic radiation in the centimeter and millimeter wavelength range. With the refractive index of laser-induced filaments being lower than the refractive index of nonionized air, arrays of such filaments can serve as a structured waveguide cladding, providing an index guiding of radar signals in a nonionized gas region. In spite of attenuation of radar radiation induced by plasma absorption, filament-array waveguides are shown to enhance radar signal transmission relative to freely propagating radar beams.
© 2007 Optical Society of America
Original Manuscript: October 19, 2006
Revised Manuscript: March 11, 2007
Manuscript Accepted: March 26, 2007
Published: August 7, 2007
Roman R. Musin, Mikhail N. Shneider, Aleksei M. Zheltikov, and Richard B. Miles, "Guiding radar signals by arrays of laser-induced filaments: finite-difference analysis," Appl. Opt. 46, 5593-5597 (2007)