Quantum correlations in the nonperturbative regime of semiconductor microcavities

The nonlinear optical response of semiconductor microcavities in the nonpertubative regime is studied in resonant single-beam-transmission and pump-probe experiments. In both cases a pronounced third transmission peak lying spectrally between the two normal modes is observed. A fully quantized theory is essential for the agreement with the experimental observations, demonstrating that quantum fluctuations leading to intraband polarizations are responsible for this effect.     

Quantum statistics of vacuum in a cavity with a moving mirror

We consider the electromagnetic field in a cavity when one of its mirrors can move along a given trajectory. Within a path-integral approach we calculate the Q-function of the electromagnetic field for individual modes inside the cavity and study the fluctuation properties of the field for different resonant cases.     

Single photon emission from a single molecule

Photon emission from a single molecule at room temperature exhibits nonclassical features. Continuous wave fluorescence excitation provides antibunching in the emitted photons sequence as a signature of the property to only emit one photon at a time. A short pulsed excitation can then produce single photons on demand, with an overall quantum efficiency up to 4.5% in our experimental setup. Direct measurement of the Mandel parameter Q(T) for an observation period of duration T follows a subpoissonian statistics on short time scale and superpoissonian statistics on longer time scale. The latter is attributed to blinking in the fluorescence due to the occurence of a metastable molecular triplet state. To cite this article: F. Treussart et al., C. R. Physique 3 (2002) 501–508.     

The asymptotic photon propagator in a nonperturbative iteration scheme of quantum electrodynamics

In connection with the possibility of a finite theory of quantum electrodynamics, the asymptotic photon-propagator is investigated in lowest order of a nonperturbative iteration technique. The result is that at this level of approximation the theory cannot be finite.     

Quantum theory of spontaneous emission by real moving atoms

We outline the solution of a fundamental problem in quantum theory which has hitherto lacked a proper solution, namely, finding the requisite quantum theoretical framework guaranteeing that the calculated inverse spontaneous emission rate of a moving atom, as a composite system of charged particles interacting with the Maxwell field, is slowed down exactly as in time dilation.     

Photon emission from a two-level atom moving in a cavity

The interaction of a two-level atom uniformly moving along a classical trajectory with a high-Q cavity quantum mode is analyzed. The dressed-state method is used to derive a recurrence formula for the transition probability of the atom with photon emission; the temporal dynamics of this probability qualitatively depends on the Doppler shift of the atomic transition frequency, on the Rabi frequency of the atom-field system, and on the detuning of the atomic transition frequency from the field mode frequency. The emission dynamics of a moving atom is very sensitive to the detuning. Rabi-type oscillations with a frequency equal to the Doppler shift can arise under certain conditions. At resonance, the emission probability of a moving atom can considerably exceed the emission probability of an atom at rest. A plane-parallel-mirror cavity and a confocal spherical-mirror cavity are considered. It is shown that the peculiarities of Doppler-Rabi oscillations must be taken into account in micromaser theory.     

Theory for photon emission from a scanning tunneling microscope

We have calculated the rate of light emission from a scanning tunneling microscope with an Ir tip probing a silver film. In the calculation we model the tip by a sphere. We find a considerable enhancement of the light emission compared with for example inverse photoemission experiments. This enhancement is explained as the result of an amplification of the electromagnetic field in the area below the microscope tip due to a localised interface plasmon. We estimate that one out of 10⁴ tunneling electrons will emit a photon in the visible range. Due to an electromagnetic decoupling of the sphere from the sample the enhanced emission is lost for photon energies above a certain value. We also find that the experimentally observed maximum in the light emission as a function of bias voltage is related to the behavior of tip-sample separation versus bias voltage.     

Possibility of observing enhanced photon bunching from two photon emission

Two photon emission into a vacuum is shown to produce a field with a second order correlation functioning g⁽²⁾ greater than two. This offers the possibility of observing an enhanced Hanbury Brown Twiss effect from two photon spontaneous emission.     

Transverse photon effect in mirror nuclei

We discuss the effect of the interactions of transverse photons with nucleons in a nucleus on the energy difference between mirror pairs of nuclei. The inclusion of this interaction energy reduces the coulomb energy anomaly by about 10% in the mirror pairs of nuclei considered. (A = 13 – 33).     

边界振动的微腔中的二能级原子

采用全量子理论，对注入腔内的二能级原子、单模腔场和振动边界(视为频率为ω_m的量子谐振子)构成的系统，在相互作用绘景中，求解了该系统的态函数随时间的演化关系，在此基础上得到了原子布居数随时间的演化关系，结果显示布居数在初始值附近振荡，这说明边界的振动是周期性的，它对原子布居数的影响也是周期性的. 关键词： 边界振动的微腔 二能级原子 布居数     

Ion and photon emission from laser-generated titanium-plasma

Titanium-plasma was obtained by nanosecond pulsed laser ablation technique. A Nd:Yag laser was employed to irradiate titanium in vacuum. The ion emission from plasma was on-line monitored by an electrostatic ion energy analyzer which permitted to measure the ion kinetic energy and charge state. The visible photon emission was monitored by an optical spectrometer. The ion energy, charge state and angular distributions, the temperature and density of the non-equilibrium plasma were investigated. The temperature gradient of the plasma plume was evaluated and discussed.     

Two-electron photon emission from metallic quantum wells

Unusual emission of visible light is observed in scanning tunneling microscopy of the quantum well system Na on Cu(111). Photons are emitted at energies exceeding the energy of the tunneling electrons. Model calculations of two-electron processes which lead to quantum well transitions reproduce the experimental fluorescence spectra, the quantum yield, and the power-law variation of the intensity with the excitation current.     

Lattice wave emission from moving cracks

Antiplane shear cracks moving in square lattices have been studied in a molecular dynamics simulation. They become unstable when a critical stress intensity at the tip is reached. Within picoseconds they accelerate to steady state velocity, which can be supersonic or not, depending on the interatomic potential. If the surface energy is low, they become supersonic; if the surface energy is high, they reach only subsonic speeds before the crystal reaches the theoretical shear strength. A simple modification of the interatomic potential switches the crystal behaviour from brittle to ductile, substituting dislocations to daughter cracks. The steady state velocities are the same, whether the model crystal is brittle or ductile. The steady state velocity is a function of the applied stress, not the stress intensity.     

Created photon distribution in a cavity with a moving wall

In the framework of inverse problems, we present an analytical solution for the problem of photon generation in a cavity with a moving wall. We give a photon distribution. With some discussions on this distribution, we point out that the case when the motion index number is 2 is of particular interest from a physical point of view and we also compute the corresponding spectrum of the created photons.     

Stability regime study of a nonlinear mirror mode-locked laser

A diode array pumped nonlinear mirror mode-locked (ML) laser is developed and the regime of the stable operation for such a system is found to occur for a little detuning of intra-cavity second harmonic phase-matching. The existing theory of mode-locking using a fast saturable absorber (FSA) is used to derive corresponding equivalent parameters for a fast nonlinear mirror saturable absorber. The condition for stable single pulse ML operation is evaluated in terms of small signal gain of the laser medium and small signal nonlinear loss. The analysis explains the experimental observations and differentiates the regime of operation in ML, Q-switching and cw mode-locking.     

Quantum state transfer between distant atoms via selectivity photon emission and absorption progresses

We proposed a simple scheme to deterministically generate three-dimensional (3D) quantum state transfer (QST) between two spatially atoms based on the selectivity photon emission and absorption progresses. In the present scheme, two M-type five-level atoms are trapped into two cavities connected by a fiber. By quantitatively discussing the evolution of system, we show that the effects of atom's spontaneous decay and photon leakage out of fiber can be suppressed in our scheme due to the presence of virtual excited processes in atom and fiber modes. Moreover, we also show that the present scheme can be extended to realize QST between distant nodes in a coupled array of optical cavity, which is very useful for the progress of the quantum information network.