NOTEDEV · Novel Type of Terahertz Devices

Novel Type of Terahertz Devices

Notedev Initial Training Network Novel Type of Terahertz Devices Terahertz (THz) sources and detectors have powerful potential for applications in biology, medicine, security and non- destructive testing. Some devices are currently in operation but, to benefit from the full potential of terahertz frequencies, there is an urgent need for developments in producing efficient, cheap, reliable, scalable and portable THz devices. Notedev has developed a range of technologies across one network. As a result, the fellows employed by the network have gained a broad training in terahertz technology. Notedev is composed of nine academic and industrial partners. The network recruited fourteen Fellows: thirteen Early Stage Researchers (ESRs) and one Experienced Researcher (ER). Four ESRs are female. The Notedev website www.notedev.eu provided both a resource for the network and an outreach tool, with scientific explanations aimed at the general public and links to extra resources. Scientific Deliverables The fabrication of a microcavity with effective polaritonic THz radiative transition An effective patch-antenna THz detector has been demonstrated. The resulting paper was highlighted as a ” must-read” and has 14 citations The polariton THz version of this device has been fabricated and tested using a lamp (for the linear regime) and a quantum cascade laser (to investigate the nonlinear regime). The technology for the fabrication of a radiation emitter based on monolayer InAs quantum wells has been developed. This technology allows the engineering of quantum states with predefined symmetry which is critical for achieving radiative THz transitions in exciton quantum well systems. Pozina, et al, Scientific Reports 5, 14911 2015, Pozina et al, Physica Status Solidi, 254, 1600402, 2017. Theory of graphene polaritons and THz emitters under optical excitation Significant progress was made in creating a comprehensive theory of quantum optics phenomena in graphene. In particular, the detailed consideration of how the properties of graphene change under intensive laser excitation. V.A.Saroka, M.V.Shuba, and M.E.Portnoi "Optical selection rules of zigzag graphene nanoribbons" Physical Review B 95, 155438 2017. Experimental evidence of magnetic field tunability of THz dielectric permittivity and magnetic permeability in multiferroics New multiferroic systems Ni3-xCoxTeO6 and Ni3-xMnxTeO6 have been discovered. Both systems exhibit spin-order-induced ferroelectric order with a huge magnetoelectric coupling. Changes of the static ferroelectric polarisation with magnetic field were observed and also the dynamic magnetoelectric coupling was demonstrated via tuning of THz spectra with an applied magnetic field. These interactions are enabled by the presence of electromagnons, which are highly sensitive to the magnetic field. The electromagnons were shown to be active in the Raman scattering spectra. Tunability of electromagnons in an external magnetic field was also observed in multiferroic BiFeO3. Skiadopoulou et al, Physical Review B, 95 184435 (2017) Skiadopoulou et al, Physical Review B 91, 174108 (2015). The Notedev Fellows 45 papers co-authored by the Notedev Fellows have been published in journals and conference proceedings, with more papers in preparation. The Fellows have given over 75 conference presentations. In addition, publications by network partners, arising from Notedev, bring the total number of publications to over 80, with more than 450 citations to date. Twelve PhD theses have been submitted by the network. The Fellows have maintained an active network, using a Google forum and have regular talks and discussions via video-link. All fellows have undertaken secondments in partner institutions as well as short secondments with industrial partners. As well as bespoke local training the Fellows have been involved in five network-wide training activities. The Fellows have benefited from general skills training including research ethics, presentation and outreach skills, time management and new media skills. The Fellows have met with scientists working in high-tech small companies and scientists who have set up their own companies. The ESRs planned their own workshop that was held in Prague and included teaching from world-leading academics from across the globe. A Notedev Facebook page was established by the ESRs and has been a good way to provide information about the work of the network as well as providing a link to outreach videos. www.notedev.eu

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