Pulling force enabled by unlocking the optical phase

We demonstrate a possibility of achieving an optical pulling force without complex beam-shaping techniques. By using optical pulses detuned from the resonant frequency of the structure, we create conditions where the spectral maxima of the excited current and of the incident field do not match. Therefore, the phase shift between the two, which controls the optical force, becomes time-dependent, thus enabling unexpected optical effects. Particularly, it is shown that tuning the central frequency of the pulse produces a temporal pulling force directed towards the illumination source.