Supplementary_video1.gif

Animated electric-field distribution (the phase of the incident field is changing) for upper polariton at 565 GHz at a low magnetic field of B = 10 mT to show the excitation of plasmonic waves acting as a loss channel for the polaritonic mode (related to Fig. 3, right panel, coupled resonator without the reflector)

Supplementary_video3.gif

Animated electric-field distribution (the phase of the incident field is changing) for upper polariton at 621 GHz at a low magnetic field of B = 10 mT to show the confined upper polariton mode in the central defect (w=1.5 μm) of the plasmonic reflectors (related to Fig. 3, left panel, coupled resonator with the reflector structure and a cap layer etched to h=90 nm)

Supplementary_video2.gif

Animated electric-field distribution (the phase of the incident field is changing) for upper polariton at 607 GHz at a low magnetic field of B = 10 mT to show the partially confined upper polariton mode in the central defect (w=1.5 μm) of the plasmonic reflectors (related to Fig. 3, central panel, coupled resonator with the reflector structure and a cap layer etched to h=80 nm)