We present a scheme to produce programmable phase- and amplitude-modulated femtosecond laser pulses in the mid-infrared regime of 3–10μm by difference frequency mixing. The 80-fs signal output of an optical parametric amplifier is shaped with a liquid-crystal mask and mixed in an AgGaS<sub>2</sub> crystal with a temporally stretched idler pulse. Without changing the mechanical alignment, we produce programmable amplitude modulations and chirped pulses at λ=3μm with energy as high has thas 1μJ . This scheme, further, allows the generation of controllable pulse sequences. The results are in good agreement with theoretical simulations.
© 2002 Optical Society of America
T. Witte, D. Zeidler, D. Proch, K. L. Kompa, and M. Motzkus, "Programmable amplitude- and phase-modulated femtosecond laser pulses in the mid-infrared," Opt. Lett. 27, 131-133 (2002)