Scientists have developed a new material that could lead to James Bond-style erasable and rewritable optical chips whose contents can be instantly erased wirelessly. The researchers used a green laser to develop a waveguide – a structure or tunnel that guides light waves from one point to another – on their nanomaterial.
They then erased the waveguide with Ultraviolet (UV) light, and re-wrote it on the same material using the green laser. “The molecules in this material are very sensitive to light, so we can use a UV light or specific light wavelengths to erase or create optical components,” said Yuebing Zheng, a professor at University of Texas at Austin in the US.
“Potentially, we could incorporate this LED into the chip and erase its contents wirelessly. We could even time it to disappear after a certain period of time,” Zheng said. The researchers believe they are the first to rewrite a waveguide, which is a crucial photonic component and a building block for integrated circuits, using an all-optical technique.
Their main advancement is a specially designed hybrid nanomaterial that is akin to a child’s Etch-A-Sketch toy – only the material relies on light and tiny molecules to draw, delete and re-write optical components.
Scientists are interested in rewritable components that use light rather than electricity to carry data because they hold potential for making devices faster, smaller and more energy-efficient than components made from silicon.
The drawback to CDs, DVDs and other state-of-the-art rewritable optical components is that they require bulky, stand-alone light sources, optical media and light detectors. The new innovation allows for writing, erasing and rewriting to all happen on two-dimensional (2D) nanomaterial, paving the way for nano-scale optical chips and circuits.
“To develop rewritable integrated nanophotonic circuits, one has to be able to confine light within a 2D plane, where the light can travel in the plane over a long distance and be arbitrarily controlled in terms of its propagation direction, amplitude, frequency and phase,” Zheng said. “Our material, which is a hybrid, makes it possible to develop rewritable integrated nanophotonic circuits,” he said.
The material starts with a plasmonic surface, which is made up of aluminium nanoparticles, on top of which sits a 280-nanometre polymer layer embedded with molecules that can respond to light. Due to quantum mechanics interactions with the light, the molecules can either become transparent, allowing the light waves to propagate, or they can absorb the light.
Another advantage of the material is that it can operate two light-transporting modes simultaneously – called the hybrid mode. The finding was published in the journal Nano Letters.