I. A. Nechepurenko

Channel spaser: Coherent excitation of one-dimensional plasmons from quantum dots located along a linear channel

We show that net amplification of surface plasmons is achieved in channel in a metal plate due to nonradiative excitation by quantum dots. This makes possible lossless plasmon transmission lines in the channel as well as the amplification and generation of coherent surface plasmons. As an example, a ring channel spaser is considered.

Highly confined surface plasmon polaritons in the ultraviolet region

Surface plasmon polaritons are commonly believed to be a future basis for the next generation of optoelectronic and all-optical devices. To achieve this, it is critical that the surface plasmon polariton modes be strongly confined to the surface and have a sufficiently long propagation length and a nanosize wavelength. As of today, in the visible part of the spectrum, these conditions are not satisfied for any type of surface plasmon polaritons. In this paper, we demonstrate that in the ultraviolet range, surface plasmon polaritons propagating along a periodically nanostructured aluminum-dielectric interface have all these properties. Both the confinement length and the wavelength of the mode considered are smaller than the period of the structure, which can be as small as 10 nm. At the same time, the propagation length of new surface plasmon-polaritons can reach dozens of its wavelengths. These plasmon polaritons can be observed in materials that are uncommon in plasmonics such as aluminum. The suggested modes can be used for miniaturization of optical devices.

Optimum gain for plasmonic distributed feedback lasers

Although nanolasers typically have low Q-factors and high lasing thresholds, they have been successfully implemented with various gain media. Intuitively, it seems that an increase in the gain coefficient would improve of characteristics of nanolasers. For a plasmonic distributed feedback (DFB) laser, we propose a self-consistent model that takes into account both spontaneous emission and the multimode character of laser generation to show that for given pumping strength, the gain coefficient has an optimal value at which the radiation intensity is at a maximum and the radiation linewidth is at a minimum.

Passively Q-switched spaser as a terahertz clock oscillator for plasmon computer

The interaction of plasmons in spaser with saturable absorber leads to pulse generation under passive Q-switching. A distributed scheme of spaser that represents a groove on metal surface filled with active medium is considered. The Maxwell–Bloch equations are used to describe generation of 1D plasmons in such a distributed spaser. The operation of the system as a terahertz clock oscillator is demonstrated with the aid of numerical experiment.

Lasing induced by resonant absorption

We theoretically demonstrate that increase of absorption with constant gain in laser systems can lead to onset of laser generation. This counterintuitive absorption induced lasing (AIL) is explained by emergence of additional lasing modes created by an introduction of an absorbing medium with narrow linewidth. We show that this effect is universal and, in particular, can be encountered in simple Fabry-Perot-like systems and doped spherical dielectric nanoresonators. The predicted behavior is robust against detuning between the resonant frequencies of gain and absorbing medium.