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Abstract Organic compounds containing luminous rare-earth ions are of interest for numerous nanophotonic and plasmonic applications, including nanoscale lasers, biosensors, and optical magnetism studies. Optical studies of Eu³⁺complexes revealed that ultra-thin LB monolayers are highly luminescent even when deposited directly on plasmonic metal, which makes these materials very promising for plasmonic applications and studies, including control and enhancement of magnetic dipole emission with a plasmonic environment. In this work, we synthesize amphiphilic complexes with various rare-earth ions Nd³⁺, Yb³⁺, and DPT ligands and show that they all are suitable for monolayer or multilayer deposition with the Langmuir–Blodgett (LB) technique. Graphical abstract 

Work function is an essential material’s property playing important roles in electronics, photovoltaics, and more recently, in nanophotonics. We have studied e昀 ects of organic, and inorganic dielectric materials on work functions of Au 昀 lms in single layered, and multilayered structures. We found that measured work function of metallic surfaces can be a昀 ected by dielectric materials situated 10–100 nm away from the metallic surface. We have found that, (i) the glass underneath ~ 50 nm gold slab reduces the work function of gold, (ii) Rh590:PMMA increases the work function of a gold 昀 lm deposited on top of the polymer, and (iii) reduces it if Rh590:PMMA is deposited on top of Au. (iv) With increase of the Rh590 concentration in PMMA, n, the work function 昀 rst decreases (at n < 64 g/l), and then increases (at n > 64 g/l). (v) The work function of a Fabry–Perot cavity or an MIM waveguide is almost the same as that of single Au 昀 lms of comparable thickness. The experimental results can be qualitatively explained in terms of a simple model taking into account adhesion of charged molecules to a metallic surface, and formation of a double layer of charges accelerating or decelerating electrons exiting the metal and decreasing or increasing the work function. 

We have studied dispersion of surface plasmon polaritons (SPPs) in the Kretschmann geometry (prism/Ag/dye-doped polymer) in weak, intermediate, and ultra-strong exciton–plasmon coupling regimes. The dispersion curves obtained in the reflection experiment were in good agreement with the simple model predictions at small concentrations of dye (Rhodamine 590, Rh590) in the polymer (Poly(methyl methacrylate), PMMA). At the same time, highly unusual multi-segment “staircase-like” dispersion curves were observed at extra-large dye concentrations, also in agreement with the simple theoretical model predicting large, small, and negative group velocities featured by different polariton branches. In a separate experiment, we measured angular dependent emission of Rh590 dye and obtained the dispersion curves consisting of two branches, one nearly resembling the SPP dispersion found in reflection and the second one almost horizontal. The results of our study pave the road to unparalleled fundamental science and future applications of weak and strong light—matter interactions. 

We explore a possibility to control magnetic dipole emission with plasmonic cavities, placing Eu³⁺emitters inside profile-modulated metal-dielectric-metal structures. Significant variations in the branching ratio of the magnetic and electric dipole transitions are observed as the function of the thickness of the intermediate layer. The experimental results are confirmed with numerical simulations which account for cavity and gap plasmon resonances and predict modifications in the spontaneous emission spectrum as the function of the gap size and a strong directionality of the emission for small thicknesses of the intermediate layer. The implications of having a competition between electric and magnetic dipole relaxation channels in Eu³⁺are discussed. 

Electrochromic polymers incorporated into plasmonic systems provide a possibility to control plasmonic properties with the applied voltage. Using gold-polyaniline (PANI) bilayers, we study the effect of coloration switching on surface plasmon polaritons propagating at the PANI-gold interface. The width of the resonance, magnitude of the plasmon wave-vector and dielectric permittivity of PANI are estimated as the function of the applied voltage.