Modification of optical properties of recrystallized tungsten due to the change in surface morphology induced by deuterium ion bombardment

Using ellipsometry and reflectometry, an anomalous change in the optical properties of recrystallized tungsten (W) as a result of bombardment with deuterium (D) ions was discovered at a sample temperature of ∼535 K. There is a qualitative difference between the value of reflectivity obtained from reflectometry measurements and that calculated from the ellipsometric data. A physical model of the discovered effect is proposed. It is shown that two processes take place at the surface of W exposed to plasma at 535 K: the appearance of blisters and a modification of the electronic structure of the surface layer.