Laser cooling of atoms to the Doppler limit

Paul D. Lett, Christoph Ira Westbrook, Richard N. Watts +4 more

Luo Xiao-Shu

The technology of laser-focused atomic deposition can be used to develop the nanostructure transfer standard of length.The atomic laser cooling is a key technique in atom lithography.A theoretical investigation of chromium atomic beam in optical traps is reported in this paper.The Doppler and sub-Doppler laser cooling forces are discussed and some characteristics of these forces are shown based on the semi-classical theory.The simulation results indicate that the atomic beam can be collimated by these laser cooling forces,especially by sub-Doppler laser cooling force and can reach the Doppler limit 120 μk,relative horizontal-speed 13.87 cm/s.

David R. Lide

This chapter describes the National Bureau of Standards’ Observation of Atoms Laser-Cooled Below the Doppler Limit , relating the context in which the publication appeared, its impact on science, technology, and the general public, and brief details about the lives and work of the author. By carefully choosing the frequency of the laser, it appeared possible to cause the atoms to emit light at a slightly higher frequency (energy) than they absorbed, carrying away the thermal energy of the atom. This frequency difference derived from the Doppler shift due to the motion of the atoms. The sub-Doppler laser-cooling temperature for cesium can be 100 times lower than the Doppler limit. Using an idea from 1954, well ahead of its time but now made possible with sub-Doppler laser cooling, the cesium atoms form an atomic fountain, undergoing a one meter high parabolic trajectory in the earth's gravitational field with a resulting hundred-fold increase in the observation time.

Hidekazu Hachisu

R. Chang, A. L. Hoendervanger, Quentin Bouton +6 more

Predictions of the Doppler theory of laser cooling are quantitatively verified for the first time using helium atoms, for which the special atomic properties, particularly its small mass and narrow transition linewidth, inhibit sub-Doppler cooling mechanisms.

Yaakov Shevy