Fig. 1: Sketch and numerical modeling of the coupled system.
From: Ultrastrong coupling between nanoparticle plasmons and cavity photons at ambient conditions
a Artistic illustration of the system: an array of plasmonic nanorods positioned in the middle of a Fabry–Pérot cavity formed by two gold mirrors. The cavity interior is filled with SiO2. The array couples to the FP cavity mode, exchanging energy at a rate g. b False-color normal-incidence absorption spectra as a function of cavity thickness with an array of 300 nm long plasmonic nanorod (width 50 nm, height 20 nm) positioned in the middle of SiO2-filled Fabry–Pérot cavity. The vertical dashed line indicates the nanorod plasmon resonance outside of the cavity. The curved lines indicate resonances of the empty FP cavity, whose even modes are not modified by the coupling. ΩR denotes plasmon–cavity mode splitting at zero detuning. c The electric field intensity (in the log scale) and the electric field lines in the vertical plane across the middle of the nanorod induced by a normally incident plane wave (polarized in the figure plane) for the coupled system of 400 nm thick cavity and 300 nm long nanorods calculated for the lower and upper polaritons.
