Acousto-optic shaping of femtosecond pulses directly in the mid-IR

A germanium acousto-optic modulator (Ge AOM) is utilized in high resolution phase and amplitude shaping of IR light between 2 and 18 mu m. Shaped waveforms centered at 4.9 mu m are demonstrated in both the time and frequency domains. The phase stability of the shaped pulse is measured by cross-correlation with an unshaped mid-IR pulse, indicating that such shaped pulses can be readily incorporated into phase sensitive experiments. This Ge AOM will enable new experiments in 21) IR spectroscopy and coherent control on the ground electronic state.