Bichromatic optical tractor beam for resonant atoms

We demonstrate a new method for generating a negative (pulling) optical force which can act on resonant particles (atoms, ions and similar ones). This method is based on the use of the gradient force rectification effect in the bichromatic field: special superposition of co-propagating Gauss and cosine-Gauss beams.

► We propose the bichromatic optical tractor beam (BOTB) for resonant atoms. ► BOTB is a special superposition of co-propagating Helmholtz–Gauss beams. ► The result of its action is negative light pressure — atom attraction to the light source. ► Negative light pressure arises as a result of the gradient force rectification. ► Range of BOTB action is much greater than the transverse size of the beam.