Sub-half-wavelength optical lattices generated by dichroic evanescent standing waves

The paper focuses on the optical lattices that are formed by evanescent standing waves, instead of running waves of the medium. It is shown that optical dipole traps with sub-half-wavelength size can be obtained on the surface of a dielectric medium by four sets of evanescent standing waves (totally eight beams) tuned at proper wavelengths. The van der Waals potential is considered and it clearly shows that the distinctive features of such scheme can form sub-half-wavelength controllable potential traps which may provide a better confinement and controlling of the atoms. Together with the development of atom chip, this method might be used to manipulate individual atoms.