Observation of Ultrafast THz Self-actions in Graphene Based Modulators - Koulouklidis, Anastasios D.; Kyriakou, Eudokia; Daskalaki, Christina; Ergoktas, M. Said; Tasolamprou, Anna C.; Kafesaki, Maria; Kocabas, Coskun; Tzortzakis, Stelios (2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021, 2021)