The general requirements for a plasma facing mirror (PFM) of a Thomson scattering system (TS) for a burning plasma experiment are (i) high and approximately constant reflectivity in the wavelength spectral range 400–800 nm; (ii) low sputtering yield and low erosion; (iii) high power damage threshold; (iv) good thermo-mechanical properties to preserve quality imaging. Rhodium-coated mirrors are chosen because they meet these requirements. Rhodium coated mirror were realized with substrates of copper and vanadium. The detailed optical characterization of these mirrors is presented: i.e., surface planarity measurements as well as roughness and reflectivity figures are presented. These data can be used for the choice of the PFM of a TS system for international thermonuclear experimental reactor.
