Periodic Reporting for period 2 - ELEPHANT (On-Chip Electronics, Photonics, Plasmonics and Antennas: A Novel Enabling Platform for sub-THz Signal Processing)
Okres sprawozdawczy: 2023-08-01 do 2025-01-31
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.
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.
The processing of the THz waves on a small photonic chip requires different fundamental building blocks. Some of them are used to encode the THz information on the optical world (modulators), some others are needed to transform this infomation (analog processing core), and some others enable the conversion back to the THz domain of the processed information signal (detectors). Furthermore, antennas are needed to interface the THz processor to the wireless world, and some especially fast electronic circuits are used to amplify the often very weak signals to usable levels for the "light processor".
In this first reporting period, we have designed novel kind of modulators optimized for the highest bandwidth and lowest possible distortions, that are currently being fabricated. We have tested different types of optical filters with enough bandwidth to process the extremely fast THz signals, based on very small (10 micrometers), low latency and low power filters. Finally, we explored new designs for photodetectors leveraging strong field confinement effects to increase their efficiency. We have also made designs for high-speed electronics needed to feed those ultra-fast photonics components.
We have been presenting our activity in more than 20 different conferences, meetings and workshops addressed to the scientific community worldwide, but also webpages, press releases and news items aimed at the general public.
In this first reporting period, we have designed novel kind of modulators optimized for the highest bandwidth and lowest possible distortions, that are currently being fabricated. We have tested different types of optical filters with enough bandwidth to process the extremely fast THz signals, based on very small (10 micrometers), low latency and low power filters. Finally, we explored new designs for photodetectors leveraging strong field confinement effects to increase their efficiency. We have also made designs for high-speed electronics needed to feed those ultra-fast photonics components.
We have been presenting our activity in more than 20 different conferences, meetings and workshops addressed to the scientific community worldwide, but also webpages, press releases and news items aimed at the general public.
Novel modulator devices have been designed and are currently in fabrication. They promise to deliver 1000 time smaller size than commercial modulators (micron scale length), low loss, sub-THz bandwidth, while offering high fidelity, efficiency and even functional flexibility for sensitive analog THz signals. New light filters with nearly 1 THz of instantaneous bandwidth have been designed and are being tested. Finally, high-efficiency THz detectors under investigation promise a a factor 10 lower conversion losses than state-of-the-art receivers.