Description
From laser cooling to light-pulse atom interferometry, precise control of light-atom interaction requires precise modulation of optical waveforms in the time-domain. To this end, Acousto-Optical Modulation (AOM) is uniquely powerful for achieving high speed, high contrast optical control. However, based on two-mode resonant Bragg diffraction, the AOM efficiency and bandwidth are prone to high-order and off-resonant perturbations. Here, following a recent work (arXiv:2110.15537), we propose and demonstrate a few new tricks to go beyond the traditional limits by modulating light with double-passing single AOMs. In the first setup, the AOM sound wave with frequency $f_S^{(0)}$ is re-imaged to itself after an optical delay of $L_d=c/f_S^{(0)}$. The setup coherently splits the Bragg-diffraction process into two. In this simple setup, we demonstrate diffraction efficiency as high as $\eta=98\%$ for both $\pm 1^{st}$-orders, when the AOM is driven at merely a fourth of the regularly required rf power. Furthermore, we find the highly efficient diffraction is accompanied by extinction of the 0th order by 18dB , thereby enabling efficient optical routing on demand. Finally, for the $+1$-order, we find the $\omega_S$ can be be deviate from $\omega^{(0)}$ substantially while maintaining $\eta>80\%$. In the 2nd setup, we still re-image the AOM sound-wave to itself, but with the propagation direction of sound field reversed. In this case, we demonstrate high-contrast modulation of AOM output to support efficient routing of a synchronized mode-locked laser. In particular, the double-pass AOM pre-scales the repetition rate of the pulsed laser from $f_{\rm rep}=4f_S^{0}/(2N+1)$ to $f_{\rm rep}=2f_S^{0}/(2N+1)$, with close to unity efficiency and $\sim18$dB side-pulse suppression efficiency. We discuss extension of the new method for synthesizing multi-frequency optical waveforms by cascading arrays of multi-pass AOMs.
| Presenter name | YuxiangZhao |
|---|---|
| online poster URL | https://ultracontrol.fudan.edu.cn/wonference/list.htm |
| How will you attend ICAP-27? | I am planning on virtual registration for online attendance |
