Abstract

The recent rapid extension of inertial confinement fusion requires more sophisticated beam control, such as uniform irradiation and dynamic wavefront control for strong coupling during the implosion process. Phase randomizing has been attained in a twelve-beam, 35-cm aperture Gekko XII glass laser system using a random phase plate (RPP) with 2-mm square, λ/2 optical thickness coated segments located randomly on the glass substrate. The RPP generates many beamlets focused on the spherical target in the far field region where the sharp speckle pattern is smoothed out by the lateral and longitudinal thermal energy transfer effects in plasma. The RPP has a sufficiently higher damage threshold of 5 J/cm² at 0.53 μm of 1-ns pulse duration.

© 1989 Optical Society of America