Publisher Summary This chapter describes the coherent population trapping in laser spectroscopy. Coherent population trapping may be also described as the pumping of the atomic system in a particular state, the coherent superposition of the atomic states, which is a nonabsorbing state. The exciting radiation creates an atomic coherence, such that the atom's evolution is prepared exactly out of phase with the incoming radiation and no absorption takes place. The chapter discusses the basic properties of an atomic system prepared with the coherent population-trapping superposition of states and outlines experimental observations concerned with the establishment of coherent trapping in different discrete systems. The chapter also discusses the theoretical and experimental aspects of trapping that involve states of the continuum and reviews the theoretical and experimental features associated with coherent population trapping in laser cooling, adiabatic transfer, lasing without inversion, pulse matching, and photon statistics. The theoretical aspect of coherent population trapping created by spontaneous emission is also discussed in the chapter.

Coherent Population Trapping in Laser Spectroscopy

Quantum optics with X-rays has long been a somewhat exotic activity, but it is now rapidly becoming relevant as precision x-ray optics and novel X-ray light sources, and high-intensity lasers are becoming available. This article gives an overview of the current state of the field and an outlook to future prospects.

X-ray quantum optics

Publisher Summary Atoms commonly do not act as isolated objects, but rather are open quantum systems, as they interact with the environment Typically, this environment is formed by the electromagnetic vacuum field The interaction of atoms with the environment modifies the atomic dynamics, with spontaneous emission as the most obvious example Spontaneous emission is generally recognized as incoherent process, which leads to decoherence and, therefore, forms a major limitation for many schemes of current theoretical and experimental interest But vacuum-induced processes can also generate coherent time evolution These coherences can be interpreted as arising from vacuum-induced transitions between different atomic states The situation becomes even more interesting if different atoms can exchange energy via the vacuum Such dipole–dipole interactions induce both coherent and incoherent atomic dynamics, leading to significant deviations from the single-atom properties Finally, a complex interplay of vacuum-induced interatomic and intraatomic dynamics may arise if several multilevel atoms are considered These vacuum-induced processes form the basis for a large number of applications, for which the vacuum-induced dynamics can be favorable, perturbing, or even both Most applications can be improved, if the vacuum-induced processes can be modified or even controlled Thus, a profound understanding of vacuum-induced processes is desirable Motivated by this, this chapter discusses vacuum-induced processes in multilevel atoms

Vacuum-Induced Processes in Multilevel Atoms

Ultrafast plasmonic field oscillations and optics of molecular resonances caused by coherent exciton-plasmon coupling

We report the experimental observation of electromagnetically induced transparency (EIT) in an inhomogeneously broadened V-type Na2 molecular system. The experiment is performed with both co- and counterpropagating arrangements for the propagation directions of the coupling and probe laser beams. In our theoretical model we employ the density matrix formalism, as well as perturbative methods for obtaining the probe field absorption profile for both open and closed systems. Simulations of the experimental data show excellent agreement with the predictions derived from the basic theory. Our fluorescent intensity measurements show that, in the copropagating configuration, the EIT plus saturation window depth is about 95%, while under similar conditions in the counterpropagating geometry we observed 40%‐45% reduction in the fluorescence signal around the line center. To separate the two simultaneously occurring mechanisms in a V-type system (i.e., EIT and saturation) that are induced by the coupling field, we have carried out theoretical calculations which show that, in the copropagating case, a significant fraction of the depth of the dip is due to the coherent effect of EIT. When the coupling and probe beams are in the counterpropagating configuration, the dip is mostly due to saturation effects alone.

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H. M. Doss

Papers

Spontaneous emission and absorption properties of a driven three-level system. II, The Λ and cascade models