High-resolution acousto-optic shaping of unamplified and amplified femtosecond laser pulses

TLDR

The authors investigate the fundamental limits of spectral pulse shaping with an acousto‑optic modulator and derive a simple expression to predict spatial‑profile distortions. They theoretically and experimentally analyze how the acousto‑optic Q parameter controls the trade‑off between diffraction efficiency and pixel resolution, and model nonidealities such as nonlinear acoustic attenuation. They experimentally demonstrate, for the first time, that shaped femtosecond pulses generated by an acousto‑optic modulator can be amplified.

Abstract

We focus theoretically and experimentally on the fundamental limitations of spectral pulse shaping using an acousto-optic modulator. We analyze the role of the relative thickness of the interaction region as dictated 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 potential nonidealities such as nonlinear acoustic attenuation. In addition, we derive a simple and intuitive expression to predict the magnitude of the distortions in the spatial profile generated by an acousto-optic-modulator spectral light modulator. Finally, we demonstrate amplification of acousto-optic-modulator-generated shaped pulses for the first time.