Development of a Digital Holography Diagnostic for Surface Characterization at ORNL

The Fusion and Materials for Nuclear Systems Division (FMNSD) at Oak Ridge National Laboratory (ORNL), in collaboration with Third Dimension Technologies (TDT), proposes to develop a digital holography (DH) surface erosion/deposition diagnostic for imaging 3D plasma facing component (PFC) surfaces in real time. Digital holography is a technique that utilizes IR lasers reflected from a material surface to form a holographic interferogram, which carries information about the topology of the surface when reconstructed. The interrogated surface (at a distance of ~ 3 m) is a region of ~ 2.3 cm x 2.3 cm, and the surface feature resolution is ~ 10 micron or better in depth, around 1 mm transverse to the beam. This is being accomplished in a multi-staged research program at ORNL: 1) establishment of a single-laser DH system “on the bench,” 2) establishment of a dual-laser DH system “on the bench,” and 3) implementation of the dual-laser DH system on the Proto-MPEX device. The status of the diagnostic development effort will be presented.