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Photobleaching is one of the basic chemical processes that occur naturally in organic molecules. In this work, we investigate the quantum dynamics of Cy 7.5 dye molecules optically coupled to Au nanorod particles and experimentally demonstrate the decrease of the photobleaching rate in this hybrid system. We discover the effect of a resonance-like behavior not observed before for any type of emitter─the photobleaching rate of the dye molecules reaches a minimum for a suitable number of molecules coupled to the nanoparticle. The manifestation of the effect is the consequence of shifts in the energy levels in the hybrid system caused by the change in the number of molecules coupled to a nanoparticle. The energy shifts are the prerequisite for the effective depopulation of the triplet level, which is responsible for the photodegradation mechanism. The discovered effect paves the way for increasing the efficiency of optoelectronic and photovoltaic devices.

Spaser nanoparticles, with ultranarrow spectral line width, small size and good biocompatibility, offer a bright prospect as potential biological probes. Sadly, over 10 years since the first demonstration, how the structure components determine their optical performance has not been clarified. Here the effects of gain layer thickness and dye emitter density on the lasing behavior and photostability of spaser nanoparticles are theoretically and experimentally addressed. Results show that for a 16 nm gold-core cavity, gain layer of 10–15 nm is adequate to maximize the spaser emission. For this type of nanoparticle–spaser system, the minimal number of dye emitters per particle, referred to as “dye threshold”, is also vital to spasing action besides the “pump threshold” of laser power. Moreover, dye emitter distribution within the gain layer could be another approach to further improve spaser performance. These contributions give us an opportunity to profoundly understand the physical essence of spaser nanoparticles and to optimize their performance for further biology application.

We propose and experimentally realize subwavelength light localization based on the optical nonlinearity of a single nonlinear element in nanoplasmonics—a split hole resonator (SHR). The SHR is composed of two basic elements of nanoplasmonics, a nanohole, and a nanorod. A peak field intensity occurs at the single spot of the SHR nanostructure. We demonstrate the use of the SHR as a highly efficient nonlinear optical element for (i) the construction of a polarization-ultrasensitive nanoelement and, as a practical application, (ii) the building up of an all-optical display.

We investigate the light transmission through a nanoaperture in a metal film deposited on a planar metamaterial. An effect of an anomalously high light transmission (up to 800%) through the nanoaperture is revealed, which we associate with the enhancement of the field at the interface of the planar structure "metamaterial-metal-film" due to the appearance of an optical Tamm state. Our numerical results are in qualitative agreement with experimental data. [ABSTRACT FROM AUTHOR]

We have predicted theoretically and verified experimentally the occurrence of a giant asymmetry of the transmission of arbitrarily polarized light propagating through a linear nonmagnetic optical system that consists of a metal film with a two-dimensional array of nanoholes in it and that is deposited on the surface of a planar dielectric photonic crystal. The asymmetry of the light transmission is caused by two factors: (i) the excitation of an optical Tamm state in the system, and (ii) the existence of many secondary lobes in the diffraction pattern. Our results are of interest for the development of efficient planar optical diodelike systems and related nanophotonic devices. [ABSTRACT FROM AUTHOR]