An experimental method to investigate the structure and kinetics of patterned surfaces using laser light diffraction

We describe a novel experimental method using the diffraction of a He–Ne laser beam to study surfaces patterned with structures on mesoscopic to macroscopic length scales. The technique provides high spatial and temporal resolution; it is not limited to periodic, artificial structures, but is also well suited to study the development of self-organized surface relief. Measurements can be performed under in situ conditions in a diffraction mode or an imaging mode, providing (1) qualitative and quantitative information on the surface structures, (2) information on time-dependent surface changes with a resolution of 10 μs or better, (3) observation of incubation processes (including determination of incubation time) in first-order, displacive phase transformations, and (4) observation of the surface in real space, in particular, the pattern evolution as a function of temperature or other parameters. As an example we show results of the application of our method to a $Ni0.63Al0.37$ single crystal undergoing a martensitic transformation.