Highly efficient THz four-wave mixing in doped silicon

• Published in: Light, science & applications Vol. 10; no. 1; p. 71
• Main Authors: Dessmann, Nils, Le, Nguyen H., Eless, Viktoria, Chick, Steven, Saeedi, Kamyar, Perez-Delgado, Alberto, Pavlov, Sergey G., van der Meer, Alexander F. G., Litvinenko, Konstantin L., Galbraith, Ian, Abrosimov, Nikolay V., Riemann, Helge, Pidgeon, Carl R., Aeppli, Gabriel, Redlich, Britta, Murdin, Benedict N.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2021; Springer Nature B.V; Nature Publishing Group
• Subjects: 140/125; 639/624/399/1099; 639/624/400/385; 639/624/400/561; Applied and Technical Physics; Atomic; Classical and Continuum Physics; Lasers; Molecular; Optical and Plasma Physics; Optical Devices; Optics; Photonics; Photons; Physics; Physics and Astronomy; Silicon
• ISSN: 2047-7538; 2095-5545; 2047-7538
• DOI: 10.1038/s41377-021-00509-6

Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica. Degenerate four-wave mixing provides a direct measure of the third-order non-linear sheet susceptibility χ (3) L (where L represents the material thickness) as well as technological possibilities such as optically gated detection and emission of photons. Using picosecond pulses from a free electron laser, we show that silicon doped with P or Bi has a value of χ (3) L in the THz domain that is higher than that reported for any other material in any wavelength band. The immediate implication of our results is the efficient generation of intense coherent THz light via upconversion (also a χ (3) process), and they open the door to exploitation of non-degenerate mixing and optical nonlinearities beyond the perturbative regime.