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1.
M.A. Noginov G. Zhu M. Bahoura J. Adegoke C. Small B.A. Ritzo V.P. Drachev V.M. Shalaev 《Applied physics. B, Lasers and optics》2007,86(3):455-460
The compensation of loss in metal by gain in interfacing dielectric has been demonstrated in a mixture of aggregated silver
nanoparticles and rhodamine 6G dye. An increase of the quality factor of surface plasmon (SP) resonance was evidenced by the
sixfold enhancement of Rayleigh scattering. The compensation of plasmonic losses with gain enables a host of new applications
for metallic nanostructures, including low- or no-loss negative-index metamaterials.
We have also predicted and experimentally observed a suppression of SP resonance in metallic nanoparticles embedded in dielectric
host with absorption.
PACS 61.46.Df; 73.20.Mf; 78.67.Bf 相似文献
2.
Maxim M. Noginov N. Noginova O. Amponsah R. Bah R. Rakhimov V.A. Atsarkin 《Journal of magnetism and magnetic materials》2008
In order to better understand the transition from quantum to classical behavior in spin system, electron magnetic resonance (EMR) is studied in suspensions of superparamagnetic magnetite nanoparticles with an average diameter of ∼9 nm and analyzed in comparison with the results obtained in the maghemite particles of smaller size (∼5 nm). It is shown that both types of particles demonstrate common EMR behavior, including special features such as the temperature-dependent narrow spectral component and multiple-quantum transitions. These features are common for small quantum systems and not expected in classical case. The relative intensity of these signals rapidly decreases with cooling or increase of particle size, marking gradual transition to the classical ferromagnetic resonance (FMR) behavior. 相似文献
3.
Equilibrium atomic geometries of rhodamine 6G (R6G) dye molecule dimers are studied using density-functional theory. Electron-energy structure and optical properties of R6G H and J dimers are calculated using the generalized gradient approximation method with ab initio pseudopotentials. Our theory predicts substantial redshifts or blueshifts of the optical absorption spectra of R6G dye molecules after aggregation in J or H dimers, respectively. Predicted optical properties of R6G dimers are interpreted in terms of interatomic and intermolecular interactions. Results of the calculations are discussed in comparison with experimental data. 相似文献
4.
We have observed stimulated emission of surface plasmon polaritons (SPPs) in dye-doped polymeric microcylinder cavities deposited onto gold and silver wires. The stimulated emission spectra featured a characteristic series of laser modes, with modal spacing corresponding to SPPs propagating at the interface between the metal and dielectric. A plasmonic microlaser adds to the toolbox of plasmonic devices and plasmonic metamaterials and enables on-chip plasmonic generation and loss compensation. 相似文献
5.
We have observed Stokes and anti-Stokes emission of Au nanoparticles suspended in methanol and rhodamine 6G dye solution. Photoluminescence of Au nanoparticles is a three-step process involving single-photon or three-photon excitation of electron-hole pairs, relaxation of excited electrons and holes, and emission from electron-hole recombination, possibly enhanced by surface plasmons. In the presence of dye, the excitation of anti-Stokes emission of gold involves two-photon absorption in rhodamine 6G molecules followed by the energy transfer to Au nanoparticles with simultaneous absorption of one pumping photon by Au. This mechanism significantly enhances anti-Stokes emission of gold nanoparticles in the presence of dye. 相似文献
6.
In garnets doped with chromium and rare-earth ions, the processes of energy transfer, including upconversion, were investigated. Their influence on laser properties is established. 相似文献
7.
8.
We have studied the influence of the front and the rear mirrors on the emission properties of neodymium random lasers at different
thicknesses of the powder layer. Introduction of external mirrors drastically reduces the lasing threshold of the random laser,
with the effect of the front mirror being more dominant. External mirrors also influence the location of the stimulated emission
region within the powder volume. The experimental results are in a good agreement with the results of the Monte-Carlo simulation.
PACS 42.55.Zz; 66.30.Pa 相似文献
9.
We have demonstrated an anti-Stokes random laser emission at lambda approximately 885 nm in micrometer-size powder of GaAs. The maximal pumping wavelength, lambda=1,300 nm, exceeded the lasing wavelength by nearly 50%. We conclude that both one- and two-photon pumping contribute to optical excitation of the material, with the two-photon pumping being a key process in creating the population inversion and gain. 相似文献
10.
M. A. Noginov V. A. Smirnov A. I. Talybov I. A. Shcherbakov 《Journal of Applied Spectroscopy》1989,51(5):1156-1161
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 5, pp. 766–772, May, 1989. 相似文献