Guiding radar signals by arrays of laser-induced filaments: finite-difference analysis

摘要

Circular arrays of plasma filaments induced by femtosecond laser pulses in atmospheric air are shownto 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.