The bright iridescent colors in butterfly wings or beetle shells don't come from any pigment molecules but from how the wings are structured—a naturally occurring example of what physicists call photonic crystals . Scientists can make their own structural colored materials in the lab, but it can be challenging to scale up the process for commercial applications without sacrificing optical precision.

Now MIT scientists have adapted a 19th-century holographic photography technique to develop chameleon-like films that change color when stretched. The method can be easily scaled while preserving nanoscale optical precision. They described their work in a new paper published in the journal Nature Materials.

In nature, scales of chitin (a polysaccharide common to insects) are arranged like roof tiles. Essentially, they form a diffraction grating , except photonic crystals only produce specific colors, or wavelengths, of light, while a diffraction grating will produce the entire spectrum, much like a prism. Also known as photonic band gap materials, photonic crystals are "tunable," which means they are precisely ordered to block certain wavelengths of light while letting others through. Alter the structure by changing the size of the tiles, and the crystals become sensitive to a different wavelength.

Enlarge / Given an actual beam of light, a beamsplitter divides it in two. Given individual photons, the behavior becomes more complicated. (credit: Wikipedia )

Ars Technica's Chris Lee has spent a good portion of his adult life playing with lasers, so he's a big fan of photon-based quantum computing. Even as various forms of physical hardware like superconducting wires and trapped ions made progress, it was possible to find him gushing about an optical quantum computer put together by a Canadian startup called Xanadu. But, in the year since Xanadu described its hardware, companies using that other technology continued to make progress by cutting down error rates , exploring new technologies , and upping the qubit count .

But the advantage of optical quantum computing didn't go away, and now Xanadu is back with a reminder that it hasn't gone away either. Thanks to some tweaks to the design it described a year ago, Xanadu is now able to sometimes perform operations with more than 200 qubits. And it's shown that simulating the behavior of just one of those operations on a supercomputer would take 9,000 years, while its optical quantum computer can do them in just a few dozen milliseconds.

This is an entirely contrived benchmark: just as Google's quantum computer did , the quantum computer is just being itself while the supercomputer is trying to simulate it. The news here is more about the potential of Xanadu's hardware to scale.