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 coloured square The University of Melbourne Atom Optics

Atom Optics - Nanofocusing

This figure shows how a standing wave (a laser beam reflected back on itself) focuses a beam of atoms. In this example, chromium atoms are directed down onto a surface, typically silicon, where they deposit to form a hard layer. Just before the atoms hit the surface, they are deflected by the standing wave of laser light rather like rain drops falling onto a corrugated iron roof. The atoms collect into lines and so form an array of narrow lines on the surface.

14k; see Science {\bf 262}, 877 (1993)

Scanning Atomic Force Microscope (AFM) image of chromium lines deposited on a silicon surface. Just prior to deposition, a standing wave of near-resonant laser light acts as an array of microcylindrical lenses, focusing the atoms into an array of parallel lines.

The standing wave is tuned to the deep-blue atomic resonance at 425.43 nanometres, and so the spacing between the low intensity troughs is half that, or 212.78nm. Thus each trough acts like a conventional cylindrical lens but only 0.2 microns across. This lens then focusses the atoms to much smaller lines, perhaps as small as 10nm.

NIST logo

Much of the work shown here was done at NIST in Gaithersburg, MD, USA with Jabez McClelland, Robert Celotta, Rajeev Gupta and others in the Electron Physics Group. See what they're doing at: NIST Electron Physics Group, or see Science 262 877 (1993).

Future Work

At Melbourne we will be working with rubidium (Rb) because the ground state resonance transition is at 780.1nm, which coincides with the wavelength of low-cost laser diodes - the same ones used in CD players. For more info on the laser diode aspects, click Diode lasers for atomic physics.

Once the lasers are running, and the vacuum system constructed, we will be able to work on experiments.

That's a small sample of some of the things we'll be doing. For more information, contact us via:

* Atom Optics
* Optics Group
* School of Physics
Created: 10 March, 1995
Last modified:
Authorised by: A/Prof. R. Scholten, School of Physics Maintained by: A/Prof. R. Scholten, School of Physics.