News

Engineered metasurfaces reflect waves in unusual directions

Developed at Aalto University, new metasurfaces can reflect light or sound waves into any desired direction or even split energy into more than one direction
Aalto University / Metasurface / photo: Sergei Tretyakov
Metasurface

In our day lives, we can find many examples of manipulation of reflected waves such as mirrors to see our reflections or reflective surfaces for sound that improve auditorium acoustics. When a wave impinges on a reflective surface with a certain angle of incidence and the energy is sent back, the angle of reflection is equal to the angle of incidence. This classical reflection law is valid for any homogenous surface. Researchers at Aalto University have developed new metasurfaces for the arbitrary manipulation of reflected waves, essentially breaking the law to engineer the reflection of a surface at will.

Metasurfaces are artificial structures, composed of periodic arranged of meta-atoms at subwavelength scale. Meta-atoms are made of traditional materials but, if they are placed in a periodic manner, the surface can show many unusual effects that cannot be realized by the materials in nature. In their article published 15 February 2019 in Science Advances, the researchers use power-flow conformal metasurfaces to engineer the direction of reflected waves.

Aalto University / Schematic representation of the functionality implemented with the metasurface /  Ana Diaz-Rubio
New metasurfaces can reflect light or sound waves into any desired direction.

‘Existing solutions for controlling reflection of waves have low efficiency or difficult implementation,’ says Ana Díaz-Rubio, postdoctoral researcher at Aalto University. ‘We solved both of those problems. Not only did we figure out a way to design high efficient metasurfaces, we can also adapt the design for different functionalities. These metasurfaces are a versatile platform for arbitrary control of reflection.’

‘This is really an exciting result. We have figured out a way to design such a device and we test it for controlling sound waves. Moreover, this idea can be applied to electromagnetic fields,’ Ana explains.

This work received funding from the Academy of Finland. The article was published in the online version of the journal on 15 February 2019.

  • Published:
  • Updated:
Share
URL copied!

Read more news

Photo by Unto Rautio. School of Business interior, stairs from the ground floor to the 1st floor.
Research & Art Published:

SUMMER INTERNSHIPS AT THE FINANCE FACULTY

We are primarily looking for students majoring in Finance, but we also welcome applications from students with other quantitatively oriented backgrounds. Completion of a Bachelor’s thesis or other relevant experience is a plus.
Creative Demo Day 29.11.2024 Aicha Manai, Kim-Niklas Antin. Sakari Heiskanen / Aalto 2024.
Campus, Cooperation Published:

Creative Demo Day event brought together arts and creative technologies from Aalto and Uniarts in Otaniemi

This Fall's creative industry pre-incubator participants from Aalto Digital Creatives and Uniarts Hub took the stage at the pitch event to present their business ideas to the public.
Mustaa puuta
Research & Art Published:

Unlocking the Mysteries of Super Black Materials: A novel wood-based solution

In the ever-evolving world of science and technology, there are certain phenomena that continue to captivate the minds of scientists, artists, and the general public alike. One such phenomenon is the enigmatic world of super black materials.
A man in a white lab coat with blue gloves holds up a vial of clear liquid while standing in front of a large microscope.
Research & Art Published:

Medical innovation makes early cancer diagnostics cheaper, faster, easier

Aalto University researcher makes two-pronged improvement on microbubble technology