Femtosecond pulse shaping in the mid infrared by difference-frequency mixing

The generation of programmable complex femtosecond. pulses in the mid infrared (3-10 mum) with high precision is reported. Designed pulse shapes in the near infrared (1-1.6 mum) are transferred to the mid infrared via difference-frequency mixing with a second infrared pulse spectrally narrowed in a zero-dispersion compressor. In particular, pulse sequences with variable relative phases have been obtained. The control of the pulse properties is achieved purely electronically, allowing for implementation into a feedback loop.