Using 'nanoantennae' to manipulate light beams opens door to new light-based technologies

March 10, 2016
Complete control of light waves would allow the miniaturization of traditional optical components, such as lenses, polarizers or beam-splitters, to nanoscale sizes while dramatically increasing their performance and resolution. Credit: Agency for Science, Technology and Research (A*STAR)

Complete control of some of the key properties of light waves – namely their polarisation and phase – at the nanoscale is of major interest for light-based technologies such as display screens, and in energy harvesting and data transmission. It would allow, for example, the miniaturization of traditional optical components, such as lenses, polarizers or beam-splitters, to nanoscale sizes. At the same time, it could dramatically increase their performance and resolution.

A novel approach to control the propagation of light at the nanoscale involves the use of so-called metasurfaces. A metasurface is a two-dimensional arrangement of nanosized particles called nanoantennae. Their geometries and material properties are cleverly designed to interact with light in a determined way. By engineering such metasurfaces, it is possible to modify the overall path of the light and, for example, make it bend or focus at a certain point of space, similar to what conventional prisms or lenses do. In the case of metasurfaces, this happens at distances that are 1,000 times smaller than the diameter of a human hair.

Researchers at the Agency for Science, Technology and Research (A*STAR) in Singapore have demonstrated that using silicon nanoparticles as nanoantennae, in place of metals used in previous research, allows full control of an incoming light beam while keeping it essentially transparent, allowing transmission rates above 85%. By controlling the spatial distribution of the , they were able to bend a light beam with record efficiencies of about 50%: a level that could be further increased by optimising the system.

When metals were used to design nanoantennae, they caused strong reflections of making them unsuitable for devices that transmit data. Heating induced in the metals also resulted in additional losses in the device, a serious drawback for real-world applications that require high efficiency. Silicon, as a semiconducting material, overcomes these issues, the A*STAR researchers found.

While the team's future research will focus on creating switchable or reconfigurable devices, together with new materials in different spectral regions, the technological challenge will be to develop fully viable ultra-flat optical devices for commercial uses.

Explore further: A simple artificial material can influence the properties of visible light

Related Stories

Exciting silicon nanoparticles

January 27, 2016

A method to characterize and design the optical properties of silicon nanoparticles for their use on silicon chips has been developed by A*STAR researchers in collaboration with colleagues from Russia, Israel and Australia. ...

Silicon-based metamaterials could bring photonic circuits

January 29, 2016

New transparent metamaterials under development could make possible computer chips and interconnecting circuits that use light instead of electrons to process and transmit data, representing a potential leap in performance.

Recommended for you

New aspect of atom mimicry for nanotechnology applications

December 2, 2016

In nanotechnology control is key. Control over the arrangements and distances between nanoparticles can allow tailored interaction strengths so that properties can be harnessed in devices such as plasmonic sensors. Now researchers ...

Engineers create prototype chip just three atoms thick

November 29, 2016

For more than 50 years, silicon chipmakers have devised inventive ways to switch electricity on and off, generating the digital ones and zeroes that encode words, pictures, movies and other forms of data.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.