MONOCHROMATIZATION OF ATOMIC WAVES BY NANOSCOPIC ECHELETTE GRATINGS

The vicinal Pt(997) surface is introduced as a high-performance nanosc opic reflection grating (echelette grating) for atomic waves. Its atom -optical properties with respect to thermal He beams are established b y a detailed high-resolution diffraction study. The absolute efficienc y of the Pt(997) echelette grating has been measured to vary between 2 and 20% depending on the He wavelength. In a double surface-scatterin g experiment the nanoscopic echelette grating has been used for active monochromatization of He atom waves down to Delta lambda/lambda = 0.6 %.