THz metamaterial/graphene optoelectronic modulators

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This project targets the realization of an innovative class of optoelectronic devices operating in the terahertz frequency range. The THz spectral region (1-10 THz correspond to vacuum wavelengths between 30 and 300 micrometers), lies between the electronics and the photonics range. This frequency range is vastly unexplored despite its huge potential in many applications, ranging from spectroscopy to communications, to imaging and astronomy. The full potential of the THz range is limited by the intrinsic hurdles inherent to working at these frequencies and by the lack of efficient devices. In particular, the basic optoelectronic building blocks, such as frequency and polarization modulators, capable of actively manipulating this radiation are currently missing, thus hindering its full exploitation in fundamental research and in industrial applications. This proposal aims to provide such tools by realizing a novel class of active integrated and efficient devices based on the interplay between metamaterial resonances and graphene. Because of their unique versatility and performance in terms of power consumption, efficiency and reconfiguration speed, these devices will be readyly implemented with already established academic /industrial environments. The main research areas where this project finds application are identified as terahertz imaging, spectroscopy, communications and quantum electronics. Terahertz imaging represents a mature technology which is currently used in diverse key sectors, ranging from security and defense, to semiconductor inspections, to non-destructive testing of pharmaceutical tables and imaging of biological samples. THz gas and solid-state spectroscopy have several applications as well: it is widely known that drugs or explosives present strong absorption features in the THz range while, conversely, plastic material are transparent to this radiation. This lends itself naturally into security screening, e.g. at airport, and into applications in drug detection. Common pollutants and greenhouse gases have unique spectral fingerprints in this frequency range, thus finding obvious applications in environmental monitoring. These devices in combination with already established sources such as the quantum cascade laser or time domain spectroscopic systems will increase the imaging capability and allow novel spectroscopic methodologies and experimental configurations. The interest in THz wireless communication stems from the saturation of the present communication frequencies and from the ambition of higher communication speed. The THz range uniquely addresses both issues, being an unallocated frequency region and with high carrier frequencies, mandatory prerequisite for achieving fast data transfer. The development of future THz communication platform, necessary passes through the development of fast and integrated frequency and polarization modulators, which are the basic components in many communication protocols. Therefore, the success of this proposal will uniquely address several future challenges in strategic public/private sectors, capable of impacting on the layman quality of life. At the same time, this proposal has the ambition to contribute to the health and progress of different academic environments such as the research area investigating novel carbon-based materials, and the quantum cascade laser community. This research in fact will help finding novel concrete implementations for 2D materials in electronic devices and establishing their utilization in the THz range. Finally, in combination with the quantum cascade laser, these devices will provide a formidable tool set for exploring novel concepts and configurations in fundamental quantum electron field, and increase the breadth of spectroscopic operations for this particular source.