Chirped-pulse single-shot diagnostic of a plasma channel

Summary form only given. Plasma channels can be used to guide high-intensity laser pulses over distances much longer than the diffraction limit, which is crucial for future laser wakefield accelerators. The structure and evolution of such a plasma channel is critical for successful guiding. In this paper, we demonstrate a single-shot diagnostic of the temporal evolution of a plasma channel over 1 ns with 10-ps resolution. In our experiment, a Nd:YAG laser pulse is focused on a line by an axicon to intensities of 10/sup 13/ W/cm/sup 2/ into an argon gas. The hydrodynamic evolution of the resulting spark forms an electron density profile suitable for optical guiding of laser pulses. A 20-nm bandwidth 35-fs pulse is stretched to 1 ns, regeneratively amplified, and used to interferometrically probe the spark. The probe pulse is synchronized to the Nd:YAG with <100-ps jitter. The interferogram is imaged by a lens and magnified tenfold by a microscope objective onto a 100-/spl mu/m-wide slit of a spectrometer. The temporal behavior of the interferogram is mapped onto the horizontal axis of the CCD camera, keeping one spatial dimension for the vertical axis.