The atom is the most elementary constituent of any model that describes the quantum nature of light–matter interaction. Because atoms emit and absorb light at welldefined frequencies, nineteenth century scientists thought of them as collections of harmonically oscillating electric dipole moments or EHDs. In the language of modern physics, the latter represent dipolar transitions among the various quantum mechanical states of an atom.
In a strict definition, the field of quantum optics deals with problems that not only require the quantization of matter but also of the electromagnetic field, with examples such as (i) generation of squeezed light or Fock states, (ii) strong coupling of an atom and a photon, (iii) entanglement of a photon with an atom and (iv) Casimir and van der Waals forces. There are also many other important topics that have been discussed within the quantum optics community but do not necessarily require a full quantum electrodynamic (QED) treatment. Examples are (i) cooling and trapping of atoms, (ii) precision spectroscopy and (iii) modification of spontaneous emission.
The simple picture of a TLS as an EHD remains very insightful and valuable to this day. Indeed, much of what we discuss in this chapter has to do with the interplay between the quantum and classical mechanical characters of dipolar oscillators. For instance, the extinction crosssection of a TLS, given by 3λ2/2π, can be derived just as well using quantum mechanics [70] or classical optics [234]. Another example, albeit more subtle, concerns the spontaneous emission rate.
A class of nonparaxial accelerating optical waves is introduced. These are beams with a Bessellike profile that are capable of shifting laterally along fairly arbitrary trajectories as the wave propagates in free space. The concept expands on our previous proposal of paraxial accelerating Bessellike beams to include beams with subwavelength lobes and/or large trajectory angles. Such waves are produced when the phase at the input plane is engineered so that the interfering ray cones are made to focus along the prespecified path. When the angle of these cones is fixed, the beams possess a diffractionfree Bessel profile on planes that stay normal to their trajectory, which can be considered as a generalized definition of diffractionless propagation in the nonparaxial regime. The analytical procedure leading to these results is based on a rayoptics interpretation of RayleighSommerfeld diffraction and is presented in detail. The evolution of the proposed waves is demonstrated through a series of numerical examples and a variety of trajectories.
Ramanfree nonlinear optical effects in high pressure gasfilled hollow
core PCF
M. Azhar, G. K. L. Wong, W. Chang, N. Y. Joly, P. St J. Russell
The effective Kerr nonlinearity of hollowcore kagomestyle photonic crystal fiber (PCF) filled with argon gas increases to similar to 15% of that of bulk silica glass when the pressure is increased from 1 to 150 bar, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressuretunable over a wide range while avoiding Raman scatteringabsent in noble gasesand having an extremely high optical damage threshold. As a result, detailed and wellcontrolled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixedfrequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability sideband and a solitoncreated dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realization of reconfigurable supercontinuum sources, wavelength convertors and shortpulse laser systems. (C)2013 Optical Society of America
Classical optics representation of the quantum mechanical translation
operator via ABCD matrices
The ABCD matrix formalism describing paraxial propagation of optical beams across linear systems is generalized to arbitrary beam trajectories. As a byproduct of this study, a onetoone correspondence between the extended ABCD matrix formalism presented here and the quantum mechanical translation operator is established.
Full photon statistics of a light beam transmitted through an
optomechanical system
Andreas Kronwald, Max Ludwig, Florian Marquardt
Physical Review A
87(1)
013847
(2013)

Journal

PDF
In this paper, we study the full statistics of photons transmitted through an optical cavity coupled to nanomechanical motion. We analyze the entire temporal evolution of the photon correlations, the Fano factor, and the effects of strong laser driving, all of which show pronounced features connected to the mechanical backaction. In the regime of singlephoton strong coupling, this allows us to predict a transition from subPoissonian to superPoissonian statistics for larger observation time intervals. Furthermore, we predict cascades of transmitted photons triggered by multiphoton transitions. In this regime, we observe Fano factors that are drastically enhanced due to the mechanical motion. DOI: 10.1103/PhysRevA.87.013847
Experimental Investigation of a Single Chrial NanoStructure Made of a
Composite Material
P. Wozniak, K. Hoeflich, S. Fritsch, S. Christiansen, P. Banzer, G. Leuchs
2013 CONFERENCE ON AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE
LASERS AND ELECTROOPTICS EUROPE (CLEO EUROPE/IQEC)
(2013)
An efficient and tunable 176550 nm source based on the emission of resonant dispersive radiation from ultrafast solitons at 800 nm is demonstrated in a gasfilled hollowcore photonic crystal fiber (PCF). By careful optimization and appropriate choice of gas, informed by detailed numerical simulations, we show that bright, high quality, localized bands of UV light (relative widths of a few percent) can be generated at all wavelengths across this range. Pulse energies of more than 75 nJ in the deepUV, with relative bandwidths of similar to 3%, are generated from pump pulses of a few mu J. Excellent agreement is obtained between numerical and experimental results. The effects of positive and negative axial pressure gradients are also experimentally studied, and the coherence of the deepUV dispersive wave radiation numerically investigated. (C) 2013 Optical Society of America
The phase shift induced by a single atom in free space
M. Sondermann, G. Leuchs
JOURNAL OF THE EUROPEAN OPTICAL SOCIETYRAPID PUBLICATIONS
8
13052
(2013)

Journal
In this article we theoretically study the phase shift a single atom imprints onto a coherent state light beam in free space. The calculations are performed in a semiclassical framework. The key parameters governing the interaction and thus the measurable phase shift are the solid angle from which the light is focused onto the atom and the overlap of the incident radiation with the atomic dipole radiation pattern. The analysis includes saturation effects and discusses the associated Kerrtype nonlinearity of a single atom.
The Role of Hole Transport in Hybrid Inorganic/Organic
Silicon/Poly(3,4ethylenedioxythiophene):Poly(styrenesulfonate)
Heterojunction Solar Cells
Matthias Pietsch, Muhammad Y. Bashouti, Silke Christiansen
JOURNAL OF PHYSICAL CHEMISTRY C
117(18)
90499055
(2013)

Journal
In this paper, the fundamental advantage of highly conductive transparent polymers as hole transport layers in hybrid solar cells is demonstrated. The substantial efficiency improvement of hybrid ntype silicon (nSi)/poly(3,4ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solar cells by adding organic solvents to the polymer dispersion is investigated, and a model that explains reasons and mechanisms for that improvement is given. Opencircuit voltages of 600 mV were measured, which are comparable to conventional diffused silicon pnjunction wafer cells. It is shown by means of Xray photoelectron spectroscopy that the PEDOT versus PSS ratio plays an important role for charge carrier transport in the PEDOT:PSS layer as well as for charge carrier separation at the nSi/PEDOT:PSS interface. A shell of insulating PSS segregates at the surface of PEDOT:PSS grains and represents a considerable barrier for charge carrier transport and charge carrier separation, influencing the conductivity of the polymer film and the opencircuit voltage of a processed solar cell, respectively. It could be demonstrated that a mixing of the PEDOT:PSS polymer blend with the organic solvent dimethylsulfoxide reduces the PSS insulator segregation at the surface of PEDOT:PSS grains and improves the performance of hybrid nSi/PEDOT:PSS solar cells.
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