Enhanced, Site-Specific Loading
Paul Griffin

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We have shown enhanced, site-specific loading of optical lattices.
Preprint physics/0504113

The light-shift of an atomic level in the presence of an laser field is given by


where alpha_0 is the static polarizability and alpha_2 is the tensor polarizability. Q is a matrix which determines the coupling of F,mFlevels, and will be discussed further. The polarizabilities can be obtained from the dipole polarizabilites of an atom in an orientated field from the following formulae:

where alpha_xx is the dipole polarizability for an atom in a laser field polarized along x and similarly for the others.

An s state is spherically symmetric and so alpha_2 is now 0. The light-shift equation is now


For Rb, the polarizability of the ground state (5s1/2) at 10.6 microns is

with the first line being in the commonly quoted atomic units and the second in SI units. For a laser power of 50 W focussed down to 70 microns this would correspond to a ground state trap depth of approximately 0.5 mK, or 10 MHz.

For the excited p state we must consider the tensor polarizability. The graph below shows the static and tensor polarizabilities for the states we consider.


 
to be continued ...

Content © Paul Griffin, Durham University 2005