(color online) (a) The maximum degree of the positive (blue circles lines) and negative (red squares lines) orientation with respect to the laser intensity ratio for a given total intensity of 2×10 W/cm² with intensity ratio . The field envelopes of (b) two-color and (c) three-color laser fields for the same total laser intensity of 2×10 W/cm². (d) The time evolution of molecular orientation created by the two-color laser field (red dotted lines) and for the three-color laser field (green solid lines). Black arrows are the optimal orientation.