Abstract
Ultra-strong light-matter interactions can be realized in various physical systems and has thus attracted many experimental and theoretical investigations [1-4]. One possible realization is to couple strongly subwavelength split ring resonators (SRR) to the Landau level transition of a two dimensional electron (or hole) gas [2,3]. In a previous work on parabolic AlGaAs/GaAs QWs, we showed that very high values of the normalized vacuum Rabi frequency Ω/ω = 0.87 can be reached [5]. Strained Ge quantum wells, which are used for the present study, are very appealing as the material exhibits a strong non-parabolicity. The non-parabolicity can be directly observed in THz spectroscopy [6,7]. The heavy-hole cyclotron resonance spin-splits at a magnetic field of B ~ 4.5 T [6,7]. A THz split ring resonator array is deposited on top of the sGe QW, as shown in a sample sketch in Fig. 1 d) with the resonances shown in Fig. 1 b). Coupling a LC-resonance at f = 0.4 THz to the single cyclotron resonance at B ~ 1.5 T leads to an anti-crossing, as shown in Fig. 1 a). In Fig. 1 c) a zoom to the LC-resonance with fitted polaritons branches is shown and reveals a normalized coupling ratio of Ω/ω = 0.25. The polaritons branches are fitted with a Hopfield-like Hamiltonian [1,2] and is in good agreement with the experiment. The dipole-like mode of the resonator couples to the spin-splitted heavy-hole cyclotron resonance at B = 4.5 T and f = 1.25 THz. Multiple polaritons can be observed [8], as shown in Fig. 1 a). A modeling of this multiple oscillator system is done by expanding the Hopfield-like Hamiltonian to include all involved oscillators.
© 2017 IEEE
PDF ArticleMore Like This
G. Scalari, J. Keller, S. Cibella, C. Maissen, R. Leoni, M. Beck, and J. Faist
EG_5_2 European Quantum Electronics Conference (EQEC) 2017
Shima Rajabali, Erika Cortese, Mattias Beck, Simone De Liberato, Jérôme Faist, and Giacomo Scalari
JTh3A.65 CLEO: Applications and Technology (CLEO:A&T) 2021
G. Scalari, C. Maissen, S. Cibella, R. Leoni, E. Giovine, P. Carelli, D. Hagenmüller, S. De Liberato, C. Ciuti, F. Valmorra, M. Beck, and J. Faist
II_1_2 International Quantum Electronics Conference (IQEC) 2013