Short Pulses Show Absolute Phase Results

Absolute phase, the phase of a carrier with respect to the envelope of a pulse, theoretically has significant effects on intense, nonlinear laser-matter interactions, but proving that the effects actually occur has posed a problem because of difficulties in stabilizing the absolute phase in powerful laser pulses. Researchers at Max Planck Institut für Quantenoptik in Garching, Germany, have circumvented this by using the symmetrical properties of 5-fs laser pulses.

The researchers, who reported their work in the Nov. 8 issue of Nature, used a Ti:sapphire laser to photoionize atoms of krypton and to measure, in two directions, the number of electrons released. They found a high probability that absolute phase was affecting interaction.