"The realization of efficient, cheap, reliable, scalable and portable terahertz (THz) radiation sources and detectors is one of the important objectives in modern applied physics. THz emitters and detectors have potential applications in biology, medicine, security and nondestructive in-depth imaging. However none of the existing THz devices satisfy the application requirements. The project consortium, which includes teams from the leading European universities: Durham, Vilnius, Paris-7, Exeter, St. Petersburg, Prague, Amiens, University of Iceland, Swiss Company ""Alpes laser"" and several industrial associated partners, proposes a broad range of new approaches aiming to bridge the ""terahertz gap"":(i) Polariton-based THz emission using microcavities in the strong coupling regime, (ii) New types and concepts of semiconducting materials for short pulsed THz emission, (iii) Carbon nanotubes and graphene as THz emitters and detectors, (iv) Application of Ferroelectric and Multiferroic materials for THz devices. To achieve this objective, we are planning to educate and train a team of collaborating young physicists and device engineers able to conduct research and exploit its application in this new area."