Evolution of a Plasma Waveguide Created during Relativistic-Ponderomotive Self-Channeling of an Intense Laser Pulse

An on-axis plasma density depression channel was observed during and after the passage of a relativistically and ponderomotively self-guided laser pulse through a plasma. Optical interferometry was used to produce time-resolved plasma density distributions, revealing the formation of a plasma waveguide. These results were complemented by the guiding of a collinear trailing pulse.