Tunable Plasmonic Ultrastrong Coupling: Emulating Dicke Physics at Room Temperature

• Published in: arXiv.org
• Main Authors: Yahiaoui, Riad, Chase, Zizwe A, Chan, Kyaw, Tay, Fuyang, Baydin, Andrey, Noe, G Timothy, Song, Junyeob, Kono, Junichiro, Agrawal, Amit, Bamba, Motoaki, Searles, Thomas A
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 27.09.2022
• Subjects: Arrays; Boson fields; Coupling; Dipole moments; Emulators; Lattice parameters; Physics - Applied Physics; Physics - Optics; Physics - Quantum Physics; Quantum optics; Quantum phenomena; Qubits (quantum computing); Room temperature; Surface plasmon resonance
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2108.02494

A system of N two-level atoms cooperatively interacting with a photonic field can be described as a single giant atom coupled to the field with interaction strength ~N^0.5. This enhancement, known as Dicke cooperativity in quantum optics, has recently become an indispensable element in quantum information technology based on strong light-matter coupling. Here, we extend the coupling beyond the standard light-matter interaction paradigm, emulating Dicke cooperativity in a terahertz metasurface with N meta-atoms. Cooperative enhancement manifested in the form of matter-matter coupling, through the hybridization of localized surface plasmon resonance in individual meta-atoms and surface lattice resonance due to the periodic array of the meta-atoms. By varying the lattice constant of the array, we observe a clear anticrossing behavior, a signature of strong coupling. Furthermore, through engineering of the capacitive split-gap in the meta-atoms, the coupling rate was cooperatively enhanced into the ultrastrong coupling regime by a factor of N^0.5. This room-temperature technology serves as a convenient quantum emulator of the dynamics of a qubit with a giant dipole moment coherently driven by a single bosonic field.