Markus Kuhn’s work on “optical eavesdropping” — reconstructing a CRT image from reflected visible light — is really interesting: <a href="https:&#x2F;&#x2F;www.cl.cam.ac.uk&#x2F;~mgk25&#x2F;ieee02-optical.pdf" rel="nofollow">https:&#x2F;&#x2F;www.cl.cam.ac.uk&#x2F;~mgk25&#x2F;ieee02-optical.pdf</a>