1 Department of Photonics Engineering, Technical University of Denmark2 Plasmonics and Metamaterials, Department of Photonics Engineering, Technical University of Denmark3 Teraherts Technologies and Biophotonics, Department of Photonics Engineering, Technical University of Denmark4 National Institute for Optoelectronics5 Center for Nanostructured Graphene, Center, Technical University of Denmark
We have investigated the terahertz-induced third-order (Kerr) nonlinear optical properties of the amorphous chalcogenide glasses As2S3 and As2Se3. Chalcogenide glasses are known for their high optical Kerr nonlinearities which can be several hundred times greater than those of fused silica. We use high-intensity, single-cycle terahertz pulses with a maximum electrical field strength exceeding 400 kV/cm and frequency content from 0.2 to 3.0 THz. By optical Kerr-gate sampling, we measured the terahertz-induced nonlinear refractive indices at 800nm to be n2 = 1.746 x 10-14 cm2/W for As2S3 and n2 = 3.440 x 10-14 cm2/W for As2Se3.