Metamaterials tuned by light

A new class of metamaterials sensitive to light showing varying elastic properties once stimulated by a blue-light laser

Thanks to their special architecture, metamaterials allows us to test our imagination by creating materials that selectively shield at certain frequencies or provide other exotic effects like cloaking. Unfortunately, current fabrication techniques have made these materials flexible only to a certain extent. The FET Open “BOHEME” project published a study in Nature Communications which sought to address this problem by making these metamaterials sensitive to light.

 

Metamaterials are heterogeneous periodic structures which can tune different types of waves i.e. electromagnetic. This new technology offers other applications often seen in spy films such as, seismic wave shields, acoustic lenses that allow subwavelength super-resolution, acoustic diodes which enable one-directional wave propagation (“I can hear you, but you cannot hear me ”), and thin coatings for sound insulation. However, one of its drawbacks lies in the limitations provided by its working nature. Once fabricated, metamaterials are operational at frequencies pre-determined by their geometrical structure.

 

Researchers from the Polytechnic University of Torino, a partner of the BOHEME project, wrote a study in Nature Communications, reporting on how they overcame this challenge. Here, they introduced their one-of-a-kind “tuneable” light responsive materials thanks to adjustable Band Gaps (CG). 3D-printed polymers were loaded with photo-reactive molecules, which possess varying elastic properties once stimulated by a blue-light laser.

 

Frequencies can therefore be varied by simply illuminating these metamaterials with an external laser. This provides considerable freedom for the material. Its dynamic structure lets it either stay transparent as certain elastic waves propagate, or if illuminated, let it turn into a very efficient barrier, or become “semi-transparent”, by simply adjusting the intensity of the light.

 

The paper published in Nature Communications is available here

 

 

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