Atom Lithography with Chromium

Standing laser waves serve as an array of lenses for a well collimated and laser cooled chromium beam. A siljcon substrate put inlo the focal plane of that array can be patterned with lines or dots with a periodicity of half the wavelength of the light [l]. We report on an intenfie beam (at 80 cm from the nomce the 5nx corresponds to an evaporation rate of 0.8 A/E) of chromium We produce up to 300 mW of laser light (425 nm) by frequency doubling a TkSaphire-laser in a KNbO3-crystal. We did systematic studies of Dopplerand Sisyphus-cooling mechanisms in different configurations and can cool the chromium beam transversely down to a few recoil units The m u l l s are in excellent agreement with quantum Monte Carlo simulations. In contrast to mechanically coUimatiiig t h P bea.m we do not loomintenuity in the atomic beam, leading to deposition timea a6 high as 10 nmimin We report on experimentfi o n wr i t ing periodic nanostracturea (see fig. 1) with chromium with standing light fields generated by (.his syfitem. The written structures are characterised with an atomic force microscope. In a fiitilrr t l t ~ p t l i e scheme will be extended to two dimensions and different patterns.