TeraHertz (THz) radiation is of growing interest for imaging and spectroscopy in various application fields such as safety, health, environment and industrial control, since in this frequency range many dielectric materials are transparent and many molecules present unique spectral signatures for their identification. However, the limitations of the current sources, required for this active Imaging, hinder its use over long distances or through thick materials.
This thesis proposes to develop a widely tunable THz power source in the form of an array of photoconductor sources excited by photomixing two infrared lasers. The aim is to integrate several dozen or even hundreds of sources on a single component, by co-integrating components made of III-V materials on a silicon photonic substrate, in order to offer an innovative solution to power and tunability problems.
This thesis work, shared between the Bordeaux and Grenoble sites, is positioned in fields with strong industrial potential: integrated photonics and silicon integration technologies. Several items will be addressed , including the study of the architecture of the complete photonic system using simulation tools, the choice of structures and materials, technological development on CEA LETI platforms, and performance characterization. A proof-of-concept with a small number of sources is planned, followed by the design of a large-scale matrix system.
The project represents a major technological challenge, but its success would pave the way for a significant improvement in the penetration capacity of THz radiation, and would also contribute to the broadening of THz application fields.