For X-Rays? This technology is sure decades away from commercialization, but it could be the way forward in a time when conventional silicon has reached its physical limits.

I wonder why people always think just one step ahead. Science is about incremental advances EVERYWHERE to eventually allow for something completely new. If everyone had your attitude we would still beat each other with wooden rods and use candles to light our houses, because you know... The de Broglie wavelength of light is just tooooo large.

I think some people don’t get that a nonlinear interferometer IS a switching element, its use is AS a logic element. In the late 70’s, Toni Bischofberger and YR Shen put a liquid crystal inside an interferometer and observed switching effects using a single shot ruby laser. The theory had previously been worked out, and there were initial experiments at Bell Labs. Shen et al used liquid crystal because they could vary the nonlinearity greatly by temperature: they were exploring that entire parametric space. Cut to 2020. So they reduced the size to the 100 micron level, so what? Electron gates are at the 10nm level in production, and experimentally, at the few atoms level. While sub diffraction optical effects have been reported, one end of the wire is still a few microns in size. So perhaps someone can find an application for these Si gates, but not in switching logic.

That's a great point, I hadn't thought of it that way before. (Well, at least for practical light wavelengths in the visible or near IR/UV).