We present the results of time-resolved interferometric measurements of the
electron-density profile in a discharge-ablated capillary waveguide. We ob
serve the development of a pronounced axial minimum in the electron-density
profile with a relative depth of as much as 60% of the axial electron dens
ity. Such a profile is suitable for channeling high-intensity laser pulses.
(C) 1999 Optical Society of America OCIS codes: 230.7370, 120.3180, 350.55
00, 350.5400, 140.7240.