Optical diagnostic suite (schlieren, interferometry, and grid image refractometry) on OMEGA EP using a 10-ps, 263-nm probe beam

Abstract

A 10-ps, 263-nm (4ω) laser is being built to probe plasmas produced on the OMEGA EP [J. H. Kelly, L. J. Waxer, V. Bagnoud, I. A. Begishev, J. Bromage, B. E. Kruschwitz, T. E. Kessler, S. J. Loucks, D. N. Maywar, R. L. McCrory et al., J. Phys. IV France 133, 75-80 (2006)]. A suite of optical diagnostics (schlieren, interferometry, and grid image refractometry) has been designed to diagnose and characterize a wide variety of plasmas. Light scattered by the probe beam is collected by an f/4 catadioptric telescope and a transport system is designed to image with a near-diffraction-limited resolution (~1 - μm full width at half maximum) over a 5-mm field of view to a diagnostic table. The transport system provides a contrast greater than 1 : 10(4) with respect to all wavelengths outside of the 263 ± 2 nm measurement range.

Efficient propagation of ultra-intense laser beam in dense plasma

“…The electron density at this location is estimated to be n c /4. For optical probing, a 4ω (λ = 263 nm) laser beam (20 mJ, 10 ps) was injected from the side in the plasma [17], which covered a view area of 3.5 × 3.5 mm 2 at the target position. The injection timing of the probe was varied in order to track the plasma channel inside the blow-off plasma.…”

Channeling of multikilojoule high-intensity laser beams in an inhomogeneous plasma

“…[19] that focusing the laser beam to n c /4 might provide the mostfavorable condition for relativistically enhanced propagation. The probe beam [20] was a 10-ps, 0.263-µm laser with 10 mJ of energy. The relative timing between the probe and channeling pulse was measured with an accuracy of better than 20 ps on each shot.…”