Optical function generator based on cascaded nonlinear mixing in a photonic crystal

We report the synthesis of femtosecond and subfemtosecond optical field waveforms using a frequency comb consisting of the first five harmonic components of a laser. The comb components are generated in a nonlinear photonic crystal An acousto-optic modulator is used for amplitude and phase control. We synthesized the electric field into specific electric field shapes, i.e. sub-cycle cosine, sawtooth, and squares, and checked the shapes through shaper-assisted linear cross-correlation. This development of arbitrary optical waveforms is a major step toward achieving the optical analog of a RF function generator. With these optical waveforms, nanoscopic control of electronic motion in atoms, molecules and matter could be realized.