  Fast, reprogrammable control over the transverse structure of light beams
plays an essential role in applications such as structured illumination
microscopy, optical trapping, and quantum information processing. Existing
technologies, such as liquid crystal on silicon spatial light modulators
(LCoS-SLMs) and digital micromirror devices (DMDs), suffer from limited refresh
rates, low damage thresholds, and high insertion loss. Acousto-optic modulators
(AOMs) can resolve the above issues, as they typically handle higher laser
power and offer lower insertion loss. By effectively mapping the temporal
radio-frequency (RF) waveforms onto the spatial diffraction patterns of the
optical field, individual AOMs have been shown to generate one-dimensional (1D)
spatial modes at a pixel refresh rate of nearly 20 MHz. We extend this concept
to enable fast modulation in a two-dimensional (2D) space using a double-AOM
scheme. We demonstrate the generation of 2D Hermite-Gaussian (HG_nm) modes with
an average fidelity of 81%, while the highest-order mode generated, HG_53,
retains a fidelity of 56%.
