Nanometer-scale spatial modulation of an inter-atomic interaction in a Bose-Einstein condensate

We demonstrate nanometer-scale spatial control of inter-atomic interactions in a Bose-Einstein condensate of ytterbium(Yb). A pulsed optical standing wave, tuned near an optical Feshbach resonance varies the s-wave scattering length continuously across the standing wave pattern. The modulated mean-field energy with a spatial period of every 278 nm is monitored by a diffraction pattern in a time-of-flight image. We observe a wide scattering length control of up to 160 nm. The demonstrated spatial modulation of the scattering length proves that the high resolution control of atomic interactions is possible.