The objective of the nanobrush project is creating arbitrary structures with a size of the order 100 nm. An atom beam of neutral chromium atoms is used to deposit atoms on existing structures, which is an additive, non-destructive process. The atom beam is created from a thermal source, making write speeds of the order 101?m/s possible. In combination with the use of chromium, this can be an interesting patterning technique for practical applications such as chip corrections and creating interconnects. Beam compression is realized by applying a lightfield that is used as an optical lens: the atom-light interaction causes atoms to experience a force, which is used to control the atomic motion and push them inward. In this thesis two options for an optical lens are investigated: an axial symmetric conical mirror (axicon mirror) with a vertex angle of 90 degrees, and a doughnut-shaped hollow beam. The hollow beam has no light intensity on the axis, so by pushing atoms towards regions of low intensity, the atom beam can be focused. The axicon mirror on the other hand is used to create a 1 r -like potential, with maximum light intensity on the axis. Here the atoms need to be pushed towards regions of high intensity to focus the atom beam. A model is developed to study the behavior of both lenses, by simulating atomic trajectories while passing one of the lenses. Laser cooling is needed to confine the atoms to a central region, and has been added to the model. The lightfield parameters are chosen so that practical implementation is possible. The simulations show that with the hollow beam a flux increase of approximately 7.5 times can be achieved in a 200 nm region, but the associated minimum spot size is 1?m. With the axicon mirror it is possible to create a spot size of approximately 200 nm, and a flux increase of approximately 4.5 times can be realized in this region.
|Date of Award||29 Feb 2008|
|Supervisor||T. Meijer (Supervisor 1) & K.A.H. van Leeuwen (Supervisor 2)|