Human scientific achievement has been marked by the technological advancement of optical lenses. Eyeglasses, telescopes, cameras, and microscopes allow us to see in a new light. A fundamental component of the Semiconductor industry is the lens.
One of the most significant developments in lens technology in recent years has been the development of artificial engineered nanoscale materials with remarkable optical properties. Georgia Tech researchers have recently demonstrated the first-ever electrically tunable photonic meta surface platform in a study published by Nature Communications.
Ali Adibi, professor in the School of Electrical and Computer Engineering, said that metasurfaces can make the optical systems very thin and that they will be found in cell phone cameras and similar electronic image systems.
The tuning measures achieved through the new platform represent a critical advancement towards the development of reconfigurable metasurfaces. The results of the study show a record eleven-fold change in the reflective properties, a large range of tuning for operation, and much faster tuning speed.
The metasurfaces are heating up.
A large range of small elements are engineered to affect the transmission and reflection of light at different frequencies in a controlled way.
Metasurfaces look like a periodic array of posts when viewed under strong microscopes.
Metasurfaces have been used to demonstrate that very thin optical devices can affect light propagation with metalenses being the most developed application.
Despite impressive progress, most metasurfaces are passive, meaning their performance cannot be changed after fabrication. Adibi and his team applied electrical heat to a special class of materials to create a platform that can be easily manufactured with high levels of optical.
The answer is provided by PCMs.
A wide range of materials can be used to form metasurfaces, including metals, oxides, and semiconductors, but they can form the most effective structures with the smallest feature sizes. During the heating and cooling process, PCMs absorb and release heat. They are called phase change because they change from one crystallization state to another during the thermal cycling process. Water changing from a liquid to a solid is a common example.
The Georgia Tech team has more complicated experiments than heating and freezing water. They have harnessed the full potential of the Ge 2 Sb 2 Te 5 (GST), which is a compound of germanium, antimony, and tellurium, because they know that the optical properties of PCMs can be altered by local heating.
The team can make active tuning of the meta surface device possible by combining the optical design with a small electrical microheater underneath. The fabricated metasurfaces were tested in characterization labs by illuminating them with laser light and measuring the properties of the reflected light in real time.
What will the future look like with tunable metasurfaces?
Metasurfaces are replacing bulky optical assembly of the past due to their ability to reflect different colors of light and device miniaturization. It is expected that the impact on technologies like LiDAR systems for cars will be immediate.
More aggressive applications like computing, augmented reality, and artificial intelligence can be imagined with further development.
Reconfigurable metasurfaces will be found everywhere as the platform continues to develop.
More information: Sajjad Abdollahramezani et al, Electrically driven reprogrammable phase-change metasurface reaching 80% efficiency, Nature Communications (2022). DOI: 10.1038/s41467-022-29374-6 Journal information: Nature Communications Citation: Shaping the future of light through reconfigurable metasurfaces (2022, May 16) retrieved 16 May 2022 from https://phys.org/news/2022-05-future-reconfigurable-metasurfaces.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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