Experimental reconstruction of photon statistics without photon counting

Experimental reconstructions of photon number distributions of both continuous-wave and pulsed light beams are reported. Our scheme is based on on/off avalanche photo-detection assisted by maximum-likelihood estimation and does not involve photon counting. Reconstructions of the distribution for both semiclassical and quantum states of light are reported for single-mode as well as for multi-mode beams.     

Magnetic field dependence of cyclotron-resonance line broadening

We report that for non-degenerate electrons an electron-impurity interaction with a screening radius larger than the cyclotron orbit radius yields a cyclotron-resonance line broadening, which decreases with increasing magnetic field. This is consistent with most measured results.     

On the broadening of the annihilation line

The broadening of annihilation line was studied with a Ge detector. The annihilation line was deconvoluted taking into account the instrumental resolution of 1.08 keV. The P_f in several metals are found. The contribution of core electrons to annihilation is deduced.     

Micromaser action in atomic clusters

Optical micromaser action is considered in atomic clusters that can be involved in separable and entangled initial correlations. An equation describing the evolution of the Glauber quasi-probability for a light field is constructed in the Fokker-Planck approximation. The statistics of radiation emitted by a cavity is analyzed.     

Micromaser operation in correlated atoms

Stimulated emission of two-level atoms in a high-Q cavity is considered under conditions when pumping produces correlated many-atomic states. Based on the many-body problem, a kinetic equation is obtained for the Glauber–Sudarshan probability, which describes the field in the Fokker–Planck approximation. The statistics of light in this approximation are determined by the atomic correlation functions of the order of no higher than the second. The noise of light is found in the regime of micromaser operation for two types of pumping producing the initial separable states with a classical correlation and entangled states. It is shown that the presence of the initial diatomic correlation enhances the intensity noise. The entangled state of atoms is found from which nonclassical light is generated with a steady-state phase and noise, which can be almost completely suppressed in the low-frequency spectral region.     

Stability criteria for lasers with mixed line broadening

The stability criteria governing the behaviour of laser oscillators are becoming increasingly well understood, and it is found that for practical applications two types of criteria must usually be distinguished. For lasers in the inhomogeneous limit these two types are essentially equal, and this study explores their behaviour as the degree of inhomogeneous broadening is varied. All lasers exhibit a combination of homogeneous and inhomogeneous line broadening, and the graphical results presented here may be used for predicting or interpreting single-mode instabilities in practical oscillators with arbitrary mixed line broadening.     

Concept of “broadening” of a Mössbauer γ photon

The previously found anomalies of radioactive decay of Mössbauer isotopes have been successively interpreted on the basis of the model of a “wave field” in a source saturated with its own decay products.     

Controllable Source of Single Photons Based on a Micromaser with an Atomic Beam without Inversion

JETP Letters - A source of single rf photons based on a micromaser with pumping atoms without population inversion is considered. Inversion is absent because atoms in the upper and lower states...     

Collision broadening of the 3.39 μm methane line

Zeitschrift für Physik A Hadrons and nuclei - Collision broadening of the 3.39 μm methane line is investigated experimentally using saturated absorption spectroscopy and theoretically by...     

On quantum-mechanical unified theories of collisional spectral line broadening

We compare the Baranger-type unified theory of line broadening with a quantum version of the binary-collision approach. For the simple model system of a two-state atom, where both treatments are well-defined, the binary-collision theory results only from the exact formalism after an inversion of an integration variable in an integral equation. On the other hand, the binary-collision theory is applicable to more general systems. In the limiting cases of the impact and the quasistatic theories, the two treatments yield identical results.     

The relativistic Doppler broadening of the line absorption profile

The classical results of Doppler broadening of the line absorption profile are generalized to a relativistic gas in thermal equilibrium by taking into account the relativistic variance of the volume absorption coefficients of the gas, as derived by L.H. Thomas. This variance produces a small correction, even in the non-relativistic approximation.     

Parabolic microstrain-like line broadening induced by random twin faulting

The broadening of diffraction lines of layer faulted and, in particular, of microtwinned microstructures is analysed in detail. Thereby, stacked layer models turn out to be valuable to simulate the diffracted intensity if the metrics of the layers pertaining to the two types of domains are described by an average metrics plus domain-specific deviations from that metrics. Characteristic changes occur for the line-broadening effects if the fault probability and the extent of deviations from the average layer metrics vary. Emphasis is put, in particular, on a regime of line broadening characterised by merging of otherwise split peaks to yield single ones for sufficiently high twin probability. These merged peaks show unusual quadratic/parabolic increase of the integral breadths with the reflection order (parabolic microstrain broadening). This type of broadening has been predicted previously for special types of microstrain broadening, and indeed the (metrical) distortions of the domains with respect to the average structure allow perceiving even the twin-faulted microstructures as, in some sense, microstrained ones. Moreover, the special situation of superstructures is analysed, where the above mentioned merging is only observed for the fundamental but not for the superstructure reflections. Inconsistent (with respect to lattice metrics) peak positions can be observed for fundamental and superstructure reflections, which can affect lattice parameters determined from diffraction patterns.     

Correlations in the quantum theory of plasma line broadening

A unified theory of plasma line broadening is obtained from a quantum kinetic equation, paralleling existing results for a classical plasma. The atom-electron interactions are shielded by equilibrium electron correlation functions and a frequency dependent dielectric function. A “ring” approximation is used to replace the classical plasma parameter expansion, for typical laboratory conditions. Atom-electron correlations are included as well as electron-electron correlations.     

Estimate of inhomogeneous line broadening in steady-state magnetic resonance

We have established relationships between the experimental and theoretical absorption and dispersion line parameters for steady-state magnetic resonance, allowing us to determine both the field characteristics (amplitude of the a.c. magnetic field) and the relaxation characteristics (longitudinal and transverse relaxation times) of the object under study.