Light pipe for high intensity laser pulses

Optical guiding of intense laser pulses over a distance of more than 20 Rayleigh lengths in a plasma is demonstrated using a two-pulse technique. The first pulse prepares a shock-driven, axially extended radial electron density profile which guides a second pulse, injected after an optimum delay which increases with mass of the plasma ions. In the intensity range considered here (10³--10¹⁴ W/cm²), the channel is observed to support mode structure reminiscent of an optical waveguide.