This internship focuses on developing a compact and efficient terahertz (THz) source using femtosecond laser-induced micrometer-size plasmas. The project aims to overcome the “THz gap” caused by the limitations of existing THz sources, which are often expensive or have low performance. At LPENS, the approach uses table-top MHz femtosecond lasers to generate two-color plasmas and obtain large signal-to-noise ratios over a wide spectrum. The work involves designing an optical setup capable of focusing ultrafast pulses while preserving temporal compression and will later include the study of Weyl semi-metals and graphene quantum dots. Conducted in collaboration with theoreticians and OIST (Japan), the project opens new perspectives in condensed matter and quantum physics.