New device that uses metasurfaces to create different images based on light and environmental conditions

Researchers have created a metasurface-based device that can produce multiple distinct images depending on the medium and wavelength of light used. Further research could be done to create simple but effective encryption devices that can store information that is only accessible with the right keys.

Andrea Di Falco, a research team leader at the University of St. Andrews in U.K. said that “our new metasurfaces give a simple and immediate readout of the environment around the device.” LightBiomedical systems that are based on biomedical technology

In Optics ExpressResearchers demonstrate a device that allows them to see a holographic butterflies with 705-nm of light. Dry conditionswhen 750-nm is combined with a caterpillar Wet conditions. Both images can be seen when 660-nm light in dry conditions is used. The metasurfaces’ selective response can be customized to work with different pre-programmed conditions.

Di Falco said, “Our holographic tools contribute to the global effort to develop the Physics and Applications of Photonic Metasurfaces, which are one among the most versatile and useful photonic tools available to researchers to encode or manipulate information using light.”

Multifunctional metasurfaces

This new work is part the ongoing efforts of the Di Falco team to develop photonic metasurfaces operating in the visible range that can be used for. biomedical applicationsThese often involve wet environments.

“Holographic Metasurfaces are especially interesting because they can deliver complex information by producing images which can be immediately interpreted without the need to add layers,” said Di Falco. “We are particularly interested in integrating different functions of photonics into one device.”

Holographic metasurfaces are capable of creating detailed images that are dependent on the properties and transmission of light. Researchers used two types meta-atoms to create holographic holographic surfaces that encode multiple images. One type of metaatom reflects light at a specific wavelength in dry conditions while the other one has high reflectivity when light is used at a different wavelength in wet conditions.

“We created a simple, resonant metaatom geometry to enhance the holographic’s response. metasurfaceDi Falco stated that environmental conditions will be taken into consideration. “This is a great way to use the surrounding medium’s refractive index as an additional degree, which allows multiplexing of information encoded within the metasurface.”

Demonstrating distinct images

The researchers evaluated the response of the holographic holographic metasurfaces to different wavelengths in air or water by quantifying their efficiency. The metasurfaces had very high contrast between images and little crosstalk. The metasurfaces produced only one image for each set of parameters. This demonstrated two-tier information encoded.

Next, the researchers will increase the selectivity for meta-atoms to create metasurfaces which distinguish between media with similar optical properties. This could be used for creating holographic sensors which produce different images when exposed at different concentrations of a substance.