HIGH-RESOLUTION ACOUSTOOPTIC SHAPING OF UNAMPLIFIED AND AMPLIFIED FEMTOSECOND LASER-PULSES

We focus theoretically and experimentally on the fundamental limitatio ns of spectral pulse shaping using an acousto-optic modulator. We anal yze the role of the relative thickness of the interaction region as di ctated by the acousto-optic Q parameter and show that varying Q allows flexibility in choosing between diffraction efficiency and pixels of resolution. We model and experimentally demonstrate the effects of pot ential nonidealities such as nonlinear acoustic attenuation. In additi on, we derive a simple and intuitive expression to predict the magnitu de of the distortions in the spatial profile generated by an acousto-o ptic-modulator spectral light modulator. Finally, we demonstrate ampli fication of acousto-optic-modulator-generated shaped pulses for the fi rst time. (C) 1997 Optical Society of America.