Atomic-beam deflection by double-Π-pulse laser technique

We have measured the deflection of a thermal sodium beam by a force existing in a field of two counterpropagating short laser pulses. This field was created by a Π-pulse train of a mode-locked (mode) (spacing 82 MHz) dye laser beam, perpendicularly crossing a thermal sodium beam and retroreflected from a mirror behind it. Unlike the spontaneous force, this Π-pulse force is not limited by saturation effects and does not heat up the sodium beam transversally. Calculations yield a maximum Π-pulse force about three times larger than the spontaneous force, being in good agreement with our experimental results.