Metasurfaces Generate Color 3D Images Under Incoherent Illumination

Researchers have created a novel technique for producing color 3D images that operate across the full visible spectral range. Metasurfaces are 2D-engineered materials that are usually made of subwavelength elements. Adjusting the light’s polarization, phase, and amplitude offers excellent control over shaping the optical wavefront.

Unlike conventional metasurface-based holography methods, the developed method does not rely on interleaved nanostructures for wavelength multiplexing or wavelength-dependent off-axis illumination. Instead, they used specifically designed aluminum nanostructures to achieve high efficiency for metasurfaces across the visible spectrum, including the three primary RGB hues.

Images of 2D buildings with 3D effects were created using a combination of specular and diffuse reflections. Therefore, an appropriate adjustment in the brightness of the light reflected from the flat metasurface in response to changes in the illumination or observation angle is necessary to ensure the accurate perception of a 3D object through shading effects. This construction functions under incoherent illumination, unlike 3D holograms.

A 3D cube picture was encoded onto the metasurface and exposed to white light as a proof of concept. The projected picture exhibits shading effects that vary depending on the incident angle, simulating the behavior of a true 3D cube.

Metasurfaces are incredibly adaptable and have the potential to advance science in a variety of fields by bringing new functionalities or by making current technology more compact and lightweight.

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