In our daily life we constantly rely on something that we cannot even see: electromagnetic waves. Those waves are what allows us, for example, to communicate with each other and access the internet on our portable devices, without any wires. In particular, there is a certain portion of those waves that offers a strong potential for many critical applications, such as next-generation wireless communications, sensing, security, medical imaging, and more. Those are the so called terahertz (THz) waves, meaning that these waves oscillate as fast as one thousand billions times per second. For example, terahertz is used in the body scanners at some airport security checks as an alternative to manually scanning travelers. In medicine, these beams could monitor the healing of complicated burns under bandage layers, without having to remove them frequently and damaging the tissue in the process. Terahertz radiation would also make it easier to distinguish tumors from healthy tissue during surgery or early cancer detection.
As important as these waves are, they are also very difficult to transport, propagate and elaborate. Even the most advanced electronic circuits, in fact, are often too lossy at those high frequencies. This limits their performance to efficiency levels that are too low for many practical applications, such as efficient steering of wireless links needed in next generation communication networks. Therefore, the potential of THz waves remains mostly untapped, and much more could be possible than what we can harness with today's technology.
The ELEPHANT project directly targets this problem: by combining the best of four worlds - namely the fastest electronics, photonics, plasmonics and antennas - it aims to create a novel enabling technology for flexible, high-fidelity and low-loss THz signal processing.
To achieve that, the key idea is to convert the THz waves (and the information carried by them) to a physical domain where they can be transported and processed with negligible loss: the optical domain. There, very compact "light circuits" can flexibly process those signals without damping their intensity and with extremely broad bandwidth - a feat that would be impossible with traditional electrical circuits. The key problems to solve are: 1. how to to convert these THz signals to the optical domain and back efficiently and with high fidelity, and 2. to build flexible light circuits that are fast enough to process THz waves.
ELEPHANT aims to build such a "light processor" with basic functional blocks (much like lego blocks), in which we want to solve the challenge of THz signal processing by creating a novel integrated platform that allows to convert THz signals to the optical domain efficiently and with high fidelity, and to process them using a low-loss photonic processing core with THz bandwidth. This is a promising path, but requires key "building blocks" that are still largely unavailable today.
In fact, while some of today's photonics blocks offer promising features - some of them discovered by the PI and his team - much work is still needed to make them suitable to deal with these weak and sensitive THz signals.
Building on the experience of the PI and his team, we are working to create and optimize those much needed elements, integrate them together and demonstrate previously unseen system with flexible THz processing capabilities.
