Real-Time Tunable Strong Coupling: From Individual Nanocavities to Metasurfaces

Abstract

Strong light−matter coupling, characterized by a coherent exchange of energy between an emitter and cavity, plays an important role in, for example, quantum information science and thresholdless lasing. To achieve strong coupling, precise spatial and spectral overlap between the emitter and cavity is required, presenting a significant challenge to move from individually strongly coupled cavities to a large number of cavity-coupled systems, as required for future practical applications. Here we demonstrate a versatile platform for realizing strong coupling that scales uniformly from individual nanocavities up to millimeter-scale metasurfaces, while the coupling strength can be tuned dynamically. Fluorescent dye molecules are sandwiched between silver nanocubes and a metallic film creating a plasmonic cavity with a mode volume of only ∼0.002 (λ/n) 3 . A prominent anticrossing behavior is observed which corresponds to a large Rabi splitting energy of 152 meV. The plasmon resonance can be tuned up to 45 nm (∼210 meV) enabling real-time control of the Rabi splitting as well as tuning from the weak to the strong coupling regime. This scalable, easily fabricated structure opens the door for use in integrated onchip nanophotonic devices.

Tunable Fluorescence from Dye‐Modified DNA‐Assembled Plasmonic Nanocube Arrays

“…[28,29] Finally, using multiple different dyes, emission of each can be regulated through an understanding of these effects and coupling to specific structures. Researchers have preliminarily explored active tunability with plasmonic patch antennas using thermoresponsive polymers as gap materials, [30,31] but such methods do not enable precise emitter coupling. Methods for coupling dye molecules into antennas include the use of macrocyclic molecules [32] or DNA origami [33] to position the dye molecules inside the gaps.…”

“…Mater. 2019, 31,1904448 www.advmat.de www.advancedsciencenews.com allowed for large-area characterization, whereas other work on similar geometries only measured PL from under individual nanocubes. [11,12] To explain the trends in PL at different periodicities, lattice and gap mode dispersions were measured experimentally at 0% and 60% ethanol in water at constant 0.5 m NaCl and calculated using finite-difference time-domain (FDTD) simulations.…”

“…Mater. 2019, 31,1904448 www.advmat.de www.advancedsciencenews.com be interacting with both modes simultaneously. The ability for two spectrally separate, yet spatially overlapping, tunable modes, to interact with the dye could be used to simultaneously produce excitation and emission enhancements.…”

“…Mater. 2019, 31,1904448 www.advmat.de www.advancedsciencenews.com plasmonic nanoantennas with individual control over in situ tunable plasmonic gap modes and in-plane photonic lattice modes, both capable of enhancing the emission behavior of fluorophores strategically placed into the antenna hotspots. Additionally, the molecular-level control over the placement of dye molecules afforded by using DNA as linkers allows for fine-tuning of plasmon-exciton interactions.…”

Optical Properties of Substrate Supported Mixtures of Silver and Gold Nanoparticles

“…The gap mode is the plasmonic response resulting from the coupling of two plasmonic materials which have been separated by a gap distance. 143,144 Herein, a thin (~50 nm) reflective metal mirror is coated with an ultra-thin (~30 nm or less) polystyrene film, then topped with a monolayer of nanoparticles. The metal mirrors used are composed of either Ag or Au; selected due to their large quality factor.…”