Enhanced, SiteSpecific Loading
Paul Griffin
News
We have shown enhanced, sitespecific loading of optical lattices.
Preprint physics/0504113
The lightshift 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,m_{F}levels, 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 lightshift equation is now
For Rb, the polarizability of the ground state (5s_{1/2}) 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 ...
