> To do this, the researchers first had to characterize the scattering medium precisely. At Utrecht University, they shone light through a layer of zinc oxide n

> To do this, the researchers first had to characterize the scattering medium precisely. At Utrecht University, they shone light through a layer of zinc oxide nanopowder deposited on a glass slide. They then used a detector on the other side to measure the light and analyse how it had been scattered by the powder. Once this has been done, Rotter explains, you can calculate “what kind of wave would be transmitted through this medium in the same way as through fresh space”. So it's not just any opaque material (and it's not even "opaque", really), and it's not just any waveform. The headline is pretty darn baity. Nonetheless, the science here is pretty cool. I could have imagined taking a scattering medium and a desired final waveform and computing the initial waveform that would produce the final waveform, but this seems to be saying that there exist waveforms that are essentially fixed points of the transform induced by the scattering medium. I wonder whether how exact that is -- whether the waveform really is identical, or whether any differences are simply hidden below the threshold of measurement sensitivity.