Source: The Register
Article note: I had to go to the Nature article to figure out why they weren't just talking about a photodiode (I've done quite a bit of fiddling with bidirectional use of photodiodes, some of which is published). They're doing crazy plasmon shit to get phase and polarization control. Relevant and neat.
Researchers affiliated with ETH Zurich have devised a multifunction picture element, or pixel, that can both emit and measure light. Traditional pixels generally do one or the other – illuminating a display screen or capturing light in a camera sensor. A team led by David Norris, professor at ETH Zurich's Optical Materials Engineering Laboratory, has found a way to combine the two functions. The research raises the possibility of two-way screens that take and present pictures, holographic displays, optical communication systems, and quantum information processing. As described in the Nature article "Fourier pixels for bidirectional light control," the ETH Zurich boffins developed a technique that involves measuring light wave interference patterns over a metallic surface. By doing so, they're able to generate "Fourier pixels" that can create and detect the amplitude, phase and polarization of optical fields. The Fourier transform is a mathematical technique that takes a function like a sound wave and returns a function representing the specific frequencies present in that sound. A Fourier pixel represents the spatial frequency of light rather than the specific brightness at a given point in an image. "Thanks to the fact that the relevant surface profiles of the pixels can be determined using Fourier analysis, we can combine the control and analysis of amplitude, phase and polarisation on a single pixel," said post-doc Sander Vonk in an ETH Zurich press release. In the near term, Norris expects to put Fourier pixels into a matrix that can be used to construct more sophisticated camera displays. The other authors included Yannik M. Glauser, David B. Seda, Hannah Niese, Boris de Jong, Matthieu F. Bidaut, Daniel Petter, Erwan Bossavit, Gabriel Nagamine, and Nolan Lassaline. ®
