Floquet Effects and Relaxation of Hot Electrons in Graphene Under Continuous-Wave Mid-infrared Irradiation

High intensity Mid-Infrared radiation can induce Floquet-Bloch states with non- trivial topology [1,2,3]. We report on the experimental observation of photoinduced Floquet-related modifications in longitudinal conductivity and transverse photoresponse in graphene Hall bars irradiated with high-power linearly and circularly-polarized continuous-wave mid- Infrared radiation at cryogenic temperatures. We connect the experimentally-observed phenomena with processes of electron heating and relaxation in Floquet-modified graphene. The observation of Floquet signatures at lower power densities and in the continuous-wave regime lifts substantial experimental restrictions, helping to unlock potential applications for light-induced manipulation of material properties [4].<br/>We acknowledge support from NSF (projects DMR CMP #2104755 and DMR CMP #2104770). The National High Magnetic FieldLaboratory is supported by the National Science Foundation through NSF/DMR-2128556 and the State of Florida.<br/>References:<br/>[1]. T. Oka, H. Aoki, Phys. Rev. B 79, 081406(R) (2009).<br/>[2]. H. Calvo et al., Appl. Phys. Lett. 98, 232103 (2011); L. E. F. Foa Torres et al. Phys. Rev. Lett. 113, 266801 (2014).<br/>[3]. J. McIver et al., Nat. Phys. 16, 38 (2020).<br/>[4]. Y.Liu et.al. Article in preparation (2024).