Periodic Reporting for period 2 - TERAOPTICS (Terahertz Photonics for Communications, Space, Security, Radio-Astronomy, and Material Science)
Reporting period: 2022-09-01 to 2025-02-28
The European Innovative Training Network (ITN) TERAOPTICS - Terahertz Photonics for Communications, Space, Security, Radio-Astronomy, and Material Science has trained a cohort of 15 early-stage researchers (ESR) in the field of THz Photonics.
Terahertz (THz) radiation is the part of the electromagnetic spectrum between infrared and microwaves, meaning it is longer in wavelength than the former and higher in frequency than the latter. It is generally defined as the frequency range of 0.3 to 3 THz – or 300 to 3000 GHz. This part of the electromagnetic spectrum is not only notoriously hard to generate and detect, but also attracted a considerable interest in recent years, owing to potential applications in high-bandwidth and high-data-rate THz communications, satellite-to-satellite wireless links, THz spectroscopy for discovering star building in radio astronomy, high-resolution imaging and localization for security and in general for non-destructive material characterization and identification. These are not just high-impact scientific topics, but with the ever-increasing interconnectivity of future industry and healthcare applications, beyond 5G technology such as THz communication put this field of research at the center of enabling technologies for growth in virtually all sectors of the economy.
Recent scientific breakthroughs such as photonics mediated generation of ultra-low phase noise THz signal generation (see also Nobel prize 2005 in physics for Hänsch et al.), THz Photonics is seen as a key enabling technology (KET) for a variety of applications. With the increasing desire in recent years to achieve a higher degree of technological independence, TERAOPTICS has played a crucial part in the training of future Engineers and Scientists capable to develop THz photonic technologies. To achieve this, the TERAOPTICS network had organized a structured research program and doctoral training in THz photonics. This training program was beyond the traditional academic research setting by incorporating open and inter-disciplinary research elements in an international and inter-sectorial network environment consisting of solely renowned, highly experienced and equipped academic and non-academic beneficiaries in the field of Terahertz Photonics. Overall the network consisted of 4 universities, 2 research institutes, 3 SMEs, and 2 industrial beneficiaries as well as 13 academic and non-academic partners.
Terahertz (THz) radiation is the part of the electromagnetic spectrum between infrared and microwaves, meaning it is longer in wavelength than the former and higher in frequency than the latter. It is generally defined as the frequency range of 0.3 to 3 THz – or 300 to 3000 GHz. This part of the electromagnetic spectrum is not only notoriously hard to generate and detect, but also attracted a considerable interest in recent years, owing to potential applications in high-bandwidth and high-data-rate THz communications, satellite-to-satellite wireless links, THz spectroscopy for discovering star building in radio astronomy, high-resolution imaging and localization for security and in general for non-destructive material characterization and identification. These are not just high-impact scientific topics, but with the ever-increasing interconnectivity of future industry and healthcare applications, beyond 5G technology such as THz communication put this field of research at the center of enabling technologies for growth in virtually all sectors of the economy.
Recent scientific breakthroughs such as photonics mediated generation of ultra-low phase noise THz signal generation (see also Nobel prize 2005 in physics for Hänsch et al.), THz Photonics is seen as a key enabling technology (KET) for a variety of applications. With the increasing desire in recent years to achieve a higher degree of technological independence, TERAOPTICS has played a crucial part in the training of future Engineers and Scientists capable to develop THz photonic technologies. To achieve this, the TERAOPTICS network had organized a structured research program and doctoral training in THz photonics. This training program was beyond the traditional academic research setting by incorporating open and inter-disciplinary research elements in an international and inter-sectorial network environment consisting of solely renowned, highly experienced and equipped academic and non-academic beneficiaries in the field of Terahertz Photonics. Overall the network consisted of 4 universities, 2 research institutes, 3 SMEs, and 2 industrial beneficiaries as well as 13 academic and non-academic partners.
The TERAOPTICS network has trained 15 ESR and published more than 50 publications in high-impact journals and international peer-reviewed conferences. The ESRs posted news about their achievements in several social media platforms which are frequently visited by several thousand viewers. Just the network’s website accounts for more than 25.000 views per month in average. The ESRs had been offered international, inter-sectorial and inter-disciplinary secondment possibilities, helping them to carry out their research in the best possible way. Although the average study time for PhD in Engineering is between 4-5 years across Europe, most of the TERAOPTICS ESRs have already achieved their PhD degrees or will finish within one year after the three-years project.
Scientifically and technically, the TERAOPTICS network has achieved major progress to overcome challenges for future commercial market breakthroughs in THz technologies. This includes (a) high output power THz sources operating over a large frequency range, (b) reduction of noise in transmitter and receiver, (c) compact and lightweight designs, and (d) the capabilities to shape or form a THz beam. An overview on the progress beyond the state of the art is provided in the next section.
The knowledge gained in the course of the scientific and technical activities of the network has already been registered (patents) or is foreseen for future IP protection. In addition, the network partners have gained expert knowledge securing their developments.
Scientifically and technically, the TERAOPTICS network has achieved major progress to overcome challenges for future commercial market breakthroughs in THz technologies. This includes (a) high output power THz sources operating over a large frequency range, (b) reduction of noise in transmitter and receiver, (c) compact and lightweight designs, and (d) the capabilities to shape or form a THz beam. An overview on the progress beyond the state of the art is provided in the next section.
The knowledge gained in the course of the scientific and technical activities of the network has already been registered (patents) or is foreseen for future IP protection. In addition, the network partners have gained expert knowledge securing their developments.
The TERAOPTICS network has focused its scientific & technological activities in the field of THz photonics on passive and active devices for to overcome challenges for future commercial exploitation.
Table 1 provides an overview of the project's developments and results. Figures 1 to 4 show examples of devices that were developed. The achieved scientific & technological progress beyond the state of the art includes the following highlights:
- Fully-packaged high-power THz photodiodes reaching mW-level output power in the respective waveguide bands. To the knowledge on the network, such rectangular-waveguide THz photodiode are not provided by any other resource in Europe at the time of the project termination.
- Fully-packaged continuous-wave photonic THz transmitter offering an operational frequency range from close to DC to THz. To the knowledge of the network, such modules are not provided by any other resource in Europe at the time of the project termination.
- Novel fully-packaged optically-pumped THz mixers in which the required LO is provided optically. Such innovative components open-up the path toward coherent frequency-domain THz applications such as imaging or spectroscopy. To the knowledge of the network, such modules are not provided by any other resource in Europe at the time of the project termination.
- Ultra-low phase-noise THz generation by optical means. The network has developed photonic ICs for optical THz generation with phase noise level below state-of-the-art electronic synthesizer.
- Fully-packaged multi-channel radio-frequency-over-fiber (RFoF) modules for transmitting digital and analog RF signals over fiber. These modules were already provided to a European system integrator for satellite communication.
- Photonic ICs for 1D and 2D THz beam steering. The photonic ICs were already successfully exploited for wireless communications in the IEEE802.15.3d THz bands. In experiments, maximum data rates of 200 Gbit/s were reached for a single THz link.
- Several passive THz components were developed including topological waveguides, metasurface lenses, and grating waveplates.
The project has had substantial impact on the academic and industrial sector. For the industrial sector it is highlighted that the European Space Agency has recently published calls to mature and exploit outcomes achieved by individual TERAOPTICS beneficiaries. This includes RFoF to replace fibers and for enabling beam steering in earth-observation satellites. Furthermore, the exploitation of TERAOPTICS technology for the test&measurement sector is currently being investigated.
Table 1 provides an overview of the project's developments and results. Figures 1 to 4 show examples of devices that were developed. The achieved scientific & technological progress beyond the state of the art includes the following highlights:
- Fully-packaged high-power THz photodiodes reaching mW-level output power in the respective waveguide bands. To the knowledge on the network, such rectangular-waveguide THz photodiode are not provided by any other resource in Europe at the time of the project termination.
- Fully-packaged continuous-wave photonic THz transmitter offering an operational frequency range from close to DC to THz. To the knowledge of the network, such modules are not provided by any other resource in Europe at the time of the project termination.
- Novel fully-packaged optically-pumped THz mixers in which the required LO is provided optically. Such innovative components open-up the path toward coherent frequency-domain THz applications such as imaging or spectroscopy. To the knowledge of the network, such modules are not provided by any other resource in Europe at the time of the project termination.
- Ultra-low phase-noise THz generation by optical means. The network has developed photonic ICs for optical THz generation with phase noise level below state-of-the-art electronic synthesizer.
- Fully-packaged multi-channel radio-frequency-over-fiber (RFoF) modules for transmitting digital and analog RF signals over fiber. These modules were already provided to a European system integrator for satellite communication.
- Photonic ICs for 1D and 2D THz beam steering. The photonic ICs were already successfully exploited for wireless communications in the IEEE802.15.3d THz bands. In experiments, maximum data rates of 200 Gbit/s were reached for a single THz link.
- Several passive THz components were developed including topological waveguides, metasurface lenses, and grating waveplates.
The project has had substantial impact on the academic and industrial sector. For the industrial sector it is highlighted that the European Space Agency has recently published calls to mature and exploit outcomes achieved by individual TERAOPTICS beneficiaries. This includes RFoF to replace fibers and for enabling beam steering in earth-observation satellites. Furthermore, the exploitation of TERAOPTICS technology for the test&measurement sector is currently being investigated.