Note: Self-characterizing ultrafast pulse shaper for rapid pulse switching

We use a high-efficiency acousto-optic modulator at the input to a two-dimensional Fourier-domain pulse shaper to achieve built-in characterization of the shaped output pulses. The acousto-optic modulator directs the beam to different vertical positions on a two-dimensional spatial light modulator, each of which can contain a different pulse shape. The undiffracted portion of the light serves as a reference beam for characterizing the shaped pulse via spectral interferometry. Pulse switching rates of 100 kHz can be achieved, making the device especially useful for quantum-control spectroscopy.