Photograph of an <a href="https://en.wikipedia.org/wiki/acousto-optic_modulator" class="extiw" title="w:acousto-optic modulator">acousto-optic modulator</a> ATM-3501A2 for optical wavelength modulation in the 100MHz range.
<a href="//commons.wikimedia.org/wiki/User:Geek3" title="User:Geek3">Geek3</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>