We demonstrate a new method for nondestructive imaging of laser-cooled atoms. This spatial heterodyne technique forms a phase image by interfering a strong reference laser beam with a weak probe beam that passes through the cold atom cloud. The figure of merit equals or exceeds that of phase-contrast imaging, and the technique can be used over a wider range of spatial scales. We show images of a dark-spot magneto-optic trap taken with imaging fluences as low as 61 pJ/cm2 at a detuning of 11Γ , resulting in 0.0004 photons scattered per atom.
© 2001 Optical Society of America
S. Kadlecek, J. Sebby, R. Newell, and T. G. Walker, "Nondestructive spatial heterodyne imaging of cold atoms," Opt. Lett. 26, 137-139 (2001)