Photography measures how much light of different color hits the photographic film. However, light is also a wave, and is therefore characterized by the phase. Phase specifies the position of a point within the wave cycle and correlates to depth of information, meaning that recording the phase of light scattered by an object can retrieve its full 3-D shape, which cannot be obtained with a simple photograph. This is the basis of optical holography, popularized by fancy holograms in sci-fi movies like Star Wars.

 

 

But the problem is that the spatial resolution of the photo/hologram is limited by the wavelength of light, around or just-below 1 μm (0.001 mm). That's fine for macroscopic objects, but it starts to fail when entering the realm of nanotechnology.

 

Now researchers from Fabrizio Carbone's lab at EPFL have developed a method to see how light behaves on tiniest scale, well beyond wavelength limitations. The researchers used the most unusual photographic media: freely propagating . Used in their ultrafast electron microscope, the method can encode in a holographic light pattern trapped in a nanostructure, and is based on an exotic aspect of electron and light interaction.

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