C A New Shearing Interferometer for Real - Time Characterization of Cryogenic Laser

As discussed in the preceding article, direct-drive inertial confinement fusion targets require a cryogenically cooled spherical shell in which the DT fuel is condensed in a uniform layer on the inner wall. Optical interferometry is the predominant technique used to characterize the thickness and uniformity of the cryogenic fuel layer. In addition to inherent optical limitations such as spherical and chromatic aberration, many of the interferometers used in the past are vibration sensitive or do not possess the adjustment versatility necessary to effectively characterize cryogenic inertial fusion targets. This article describes a new and unique shearing interferometer developed at LLE and implemented on the OMEGA target chamber for real-time characterization of cryogenic inertial fusion targets along two orthogonal views.