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Amphiphilic complexes with luminescent rare earth metal ions suitable for Lanmuir-Blodgett (LB) deposition have been synthesized. LB monolayers with closely packed Eu complexes deposited directly on silver demonstrate significant far-field emission in contrast to the theoretical predictions of full quenching. Angular radiation and polarization patterns of the electric and magnetic dipole emission of Eu³⁺point to a high excitation efficiency of surface plasmon polaritons. Different luminescent behavior of closely packed emitters in comparison to diluted systems is tentatively attributed to the collective state of emitters in LB layers formed via near-field coupling with surface plasmons.

 

Abstract We have studied effects of metal–dielectric substrates on photopolymerization of [2,2ʹ-Bi-1H-indene]-1,1ʹ-dione-3,3ʹ-diyl diheptanoate (BITh) monomer. We synthetized BITh and spin-coated it onto a variety of dielectric, metallic, and metal–dielectric substrates. The films were exposed to radiation of a UV–Visible Xe lamp, causing photo-polymerization of monomer molecules. The magnitude and the rate of the photo-polymerization were monitored by measuring the strength of the ~ 480 nm absorption band, which existed in the monomer but not in the polymer. Expectedly, the rate of photo-polymerization changed nearly linearly with the change of the pumping intensity. In contrast with our early study of photo-degradation of semiconducting polymer P3HT, the rate of photo-polymerization of BITh is getting modestly higher if the monomer film is deposited on top of silver separated from the monomer by a thin insulating MgF 2 layer preventing a charge transfer. This effect is partly due to a constructive interference of the incident and reflected light waves, as well as known in the literature effects of metal/dielectric substrates on a variety of spectroscopic and energy transfer parameters. At the same time, the rate of photopolymerization is getting threefold larger if monomer is deposited on Ag film directly and charge transfer is allowed. Finally, Au substrates cause modest (~ 50%) enhancement of both monomer film absorption and the rate of photo-polymerization. 

We have studied poly(methyl methacrylate) (PMMA) films doped with rhodamine 6G and rhodamine B laser dyes as potential nonlinear material components for nanophotonics. For both dyes, the optimal concentrations, at which the emission excited via the two-photon-absorption (TPA) process is maximized, have been determined. Despite relatively large values of TPA cross sections obtained in this study, the characteristic pumping densities needed to observe pronounced nonlinear effects substantially exceed the laser damage threshold for Au or alternative plasmonic materials. This makes the studied laser dyes unsuitable for some of the intended nanophotonics applications.

 

We have studied spectra and angular distribution of emission of Rhodamine 6G dye in Fabry-Perot cavities in weak and strong coupling regimes and demonstrated control of the strong coupling with the pumping intensity. 

We have studied emission kinetics in dye-doped polymeric films (HITC:PMMA), deposited on top of glass and silver and embedded in Fabry–Perot cavities (metal-insulator-metal waveguides). For highly doped films on glass, we observed strong concentration quenching, as evidenced by a dramatic shortening of the emission kinetics, consistent with our previous studies. However, for the same dye-doped films on top of silver, slower emission kinetics were observed despite the high decay rates of individual dye molecules near the metallic surface. The concentration quenching rates in Fabry–Perot cavities were nearly identical to those of HITC:PMMA films deposited on top of silver. These findings are explained within a theoretical model for the inhibition of Förster energy transfer near a metallic surface. Furthermore, the emission kinetics of the dye-doped films on top of silver were approximately single exponential—consistent with the strong coupling of excited molecules with propagating surface plasmons.

 

We found that inhibition of concentration quenching of HITC dye in Fabry-Perot cavities is almost similar to that on top of silver. Low convexity of the emission kinetics suggests strong coupling mediated by surface plasmons. 

We have studied, both theoretically and experimentally, the excitation of volume modes in a lamellar metal/dielectric metamaterial with hyperbolic dispersion. The highly efficient light penetration through tens of metamaterial layers is consistent with a relatively low propagation loss. The volume modes were found to be highly sensitive to the surface roughness of the layers, which can be a detrimental factor in device applications.

 

We show that concentration quenching of emission of dye molecules – an energy transfer to quenching centers – is inhibited in subwavelength Fabry-Perot cavities (or metal-insulator-metal, MIM, waveguides).