Simple reflection anisotropy microscopy set-up for CO oxidation studies

Reflection anisotropy microscopy (RAM) is a tool to monitor the optical anisotropy of surfaces with spatial resolution (Rotermund et al 1995 Science 270 608–10). It has been applied to pattern formation during CO oxidation on Pt(110), where it provides a high sensitivity for surface reconstruction and partially also for the coverage with reaction educts (Heumann 2000 Dissertation TU-Berlin). However, the spatial resolution of RAM and the alignment procedure of the optical components were not satisfactory. Here, we give a detailed description of a new set-up, which employs a simple polarizing beam splitter cube as an analyser instead of a Foster prism, offering a higher spatial resolution (<10 μm) and easier alignment of the optical components while retaining the high sensitivity for surface structure. Polarization contrast and spatial resolution of the new set-up are systematically measured, and applications to CO oxidation on uniform and microstructured Pt(110) single crystals are presented.