Your smartphone’s display glass could soon do much more than just look pretty. That’s what researchers from Polytechnique Montréal have just established by creating laser-written light-guiding systems that are efficient enough to be developed for commercial use.
This revolutionary technology could, for instance, embed the display glass with layer upon layer of sensors, sensitive enough to take your temperature, assess your blood sugar levels if you’re diabetic or even analyze your DNA.
This discovery offers limitless possibilities. “We’re opening Pandora’s box at the moment,” says Raman Kashyap, professor of electrical engineering and engineering physics at Polytechnique Montréal. “Now that this technique is viable, what remains is to invent new uses for it. This is why we are actively looking to partner with industry to develop this technology.”
An article published in The Optical Society’s (OSA open-access photonics journal Optics Express describes how Polytechnique researchers succeeded in using infrared light to integrate their see-through temperature-sensing and phone-authentication systems into Gorilla Glass, a strong, dense glass that’s now used in most smartphones.
“It’s easy to imagine how the technology could also eventually allow computing devices to be embedded into any glass surface, such as windows, tabletops, telephone screens, creating totally transparent tactile surfaces,” says Jérôme Lapointe, lead researcher and doctoral student at Polytechnique Montréal. “It would be like adding a new dimension to the real world that our eyes can see.”
You would simply need to place the screen of your smartphone in front of your field of vision to get information about what you’re seeing. By touching the screen, the details would appear. The potential for interaction is unlimited. At the museum, for example, you could hold your phone screen in front of a work to learn all about it. On the street, GPS applications would become obsolete; to find a restaurant, hotel, or tourist attraction, you would just have to scan your surroundings to find what you’re looking for.
For this science fiction to become reality, quality transparent devices first have to be made within the glass used in smartphones. To do this successfully, Polytechnique’s researchers turned to photonics. They used lasers to carve out transparent pathways called waveguides into the glass. These waveguides act as tunnels that channel light, analogous to the way electronic wires convey electrical signals, and form the basis for a variety of applications.
The challenge for the researchers was to make high-quality devices that could interact directly with the outside world. They created a temperature sensor that consists of one straight and one curved waveguide. When the glass heats up, it expands and changes the path length of the waveguides. By measuring how the light that emerges from one waveguide interferes with light from the other, the device can measure the temperature of anything it touches.
To create the smartphone authentication system, Polytechnique researchers used waveguides with tiny holes at various locations. The light that escapes through these holes creates a pattern that is unique to their arrangement. The idea is that each phone would have its own unique pattern, like a fingerprint, which could then be read by an infrared detector to confirm the identity of the phone as an additional layer of security for making financial transactions using smartphones.