Nonclassical light sources have a vital role in quantum optics as they offer a unique resource for studies in quantum technology. However, their applicability is restricted by their low intensity, while the development of new schemes producing intense nonclassical light is a challenging task. In this perspective article, we discuss potential schemes that could be used towards the development of high photon flux nonclassical light sources and their future prospects in nonlinear optics.

Electrons and photons can coexist as a single entity called a surface plasmon—an elementary excitation found at the interface between a conductor and an insulator. Because of their hybrid electric and photonic nature, plasmons allow photons to be precisely controlled on the nanoscale. Plasmons are evident in the vivid hues of rose windows, which derive their color from small metallic nanoparticles embedded in the glass. They also provide the basis for color-changing biosensors (such as home pregnancy tests), photothermal cancer treatments, improved photovoltaic cell efficiencies, and nanoscale lasers. While surface plasmons were first identified nearly 55 years ago, many of their exciting applications are yet to come. This issue of MRS Bulletin reviews the progress and promise of plasmonics—from the characterization tools that have allowed nanometer-scale probing of plasmons to the new materials that may enable low-loss, active, and quantum plasmonics. Within reach are applications ranging from integrated plasmonic circuits for nanophotonic computation to plasmonic optical tweezers for manipulation of nano-sized particles and proteins.

We consider two atomic transitions excited by two variable laser fields in a three-level system. We study the soliton-pair propagation out of resonance and under thermal bath effect. We present general analytical implicit expression of the soliton-pair shape. Furthermore, we show that when the coupling to the environment exceeds a critical value, the soliton-pair propagation through three-level atomic system will be prohibited.

The statistical properties of a population of immigrant pairs of individuals subject to loss through emigration are calculated. Exact analytical results are obtained which exhibit characteristic even–odd effects. The population is monitored externally by counting the number of emigrants leaving in a fixed time interval. The integrated statistics for this process are evaluated and it is shown that under certain conditions only even numbers of individuals will be observed.