Calcium cyanurate is synthesized by reacting calcium chloride with potassium cyanate following a solid-state reaction. The formation of the new compound Ca3(O3C3N3)2 (CCY), which occurs by the cyclotrimerization of cyanate ions, was examined thermoanalytically and the crystal structure was determined by single-crystal structure analysis. The structure of CCY is closely related to the structure of the well-known oxoborate β-BaB2O4 (BBO). Second harmonic generation (SHG) measurements on crystal powders show a higher SHG efficiency for CCY than for BBO by about one order of magnitude.

This work demonstrates for the first time that one-photon luminescence in gold nanorods is an entirely plasmon-induced process. To achieve this goal, we used confocal microscopy in combination with higher order laser modes as well as light spectroscopy. We show that gold nanorod luminescence can be produced in three different ways: first, by directly exciting their longitudinal and transversal plasmon modes; second, by an energy transfer from the transversal to the longitudinal plasmon mode promoted by electron−holes pairs; and third, by conversion of directly excited electron holes pairs into the longitudinal plasmon mode.

We use raster-scanning confocal microscopy in combination with radially and azimuthally polarized laser excitation for mapping the three-dimensional (3D) orientation of individual spatially isolated gold nanorods (GNRs). The simultaneous acquisition of both the elastic scattering patterns and the one-photon luminescence patterns of the same GNR allows for determining both the particle position and the orientation with high precision. By analyzing experimental patterns and comparing them to theoretical results obtained by computer simulations, we establish a complete 3D photoluminescence map of single GNRs. Both elastic scattering and luminescence patterns of the same particle are found to display modifications of the refractive index of the dielectric environment. The polarization dependence of GNRs photoluminescence suggests a plasmon-mediated process.

While single-molecule fluorescence from emitters with high quantum efficiencies such as organic dye molecules can easily be detected by modern apparatus, many less efficient emission processes such as Raman scattering and metal luminescence require dramatic enhancement to exceed the single-particle detection limit. This enhancement can be achieved using resonant optical systems such as plasmonic particles or nanoantennas, the study of which has led to substantial progress in understanding the interaction of quantum emitters with their electromagnetic environment. This review is focused on the advances in measurement techniques and potential applications enabled by a deeper understanding of fundamental optical interaction processes occurring between single quantum systems on the nanoscale. While the affected phenomena are numerous, including molecular fluorescence and also exciton luminescence and Raman scattering, the interaction itself can often be described from a unified point of view. Starting from a single underlying model, this work elucidates the dramatic enhancement potential of plasmonic tips and nanoparticles and also the more deterministic influence of a Fabry-Pérot microresonator. With the extensive knowledge of the radiative behavior of a quantum system, insight can be gained into nonradiative factors as well, such as energy transfer phenomena or spatial and chemical configurations in single molecules.

In this study we demonstrate the impact of temperature on the luminescence emission of plasmonic nanoparticles. We examine the optical properties of single gold nanorods (GNRs) in the temperature range 1.6–295 K by confocal microscopy. Decreasing temperature leads to a reduction of the full width at half-maximum (fwhm) of the luminescence spectra, thus we can conclude that the damping of the plasmonic oscillation is strongly reduced. The main contribution to the dephasing mechanism is electron–phonon scattering and we are able to determine its contribution to the dephasing using quantitative simulations, which can describe the temperature dependent dephasing of plasmonic nanoparticles.