Intensity correlations of thermal light

We demonstrate measurement of normalized Glauber’s intensity correlation functions of different orders using an array photodetector. As the light source, we use a laser beam scattered by a rotating ground-glass disc, which has statistics close to that of thermal light. We compare the measurements of the normalized correlation functions to that of the difference-intensity variance and show that they are in a certain sense complementary. The independence of the variance measurement on the number of temporal modes has been demonstrated for the first time. Different versions of high-order ghost imaging are also realized and characterized quantitatively.     

Intensity correlations in resonance fluorescence from two atoms

The intensity correlation function of resonance fluorescence radiation from a two atom system is calculated in the weak-field limit.     

Intensity correlations and anticorrelations in a three-level cascade system

We study the intensity–intensity correlations of the radiation emitted on probe transition in a three-level cascade electromagnetically-induced transparency (EIT) scheme. Further, we show that by applying even a very weak incoherent pump, the nature of the emitted radiation can be switched from classical to non-classical without significantly affecting the probe transparency.     

Intensity correlations in the presence of additive background noise

The mean value of the intensity correlation function and intensity spectrum of a bar object are evaluated when a spatialy random intensity is added to the deterministic object. The mean value of both functions depends upon two terms in addition to the usual term involving the deterministic object, one involves the mean and the other involves the covariance of the random background intensity.     

Spatial quantum correlations in multiple scattered light

We predict a new spatial quantum correlation in light propagating through a multiple scattering random medium. The correlation depends on the quantum state of the light illuminating the medium, is infinite in range, and dominates over classical mesoscopic intensity correlations. The spatial quantum correlation is revealed in the quantum fluctuations of the total transmission or reflection through the sample and should be readily observable experimentally.     

Parity violation correlations in light muonic atoms

The 2S-1S transition in light muonic atoms is very sensitive to parity violation correlations induced via neutral currents. Observables depending on these transitions such as the photon polarization and the angular correlation between the emitted radiation and the atom polarization are a clear signal of weak neutral currents in atoms. We find the relation between the lepton and quark couplings and these observables emphasizing the effect of the nuclear spin. The results expected in muonic, atoms μ-⁴He and μ-³He are given.     

Intensity correlations of general type beam in weakly turbulent atmosphere

In weakly turbulent atmosphere, intensity correlations at the receiver plane are formulated for a general type optical beam. Evaluating our formula at the appropriate source parameters versus the diagonal distance, intensity correlations for cos Gaussian, cosh Gaussian, annular and flat-topped Gaussian beams are obtained. As compared to Gaussian beam, intensity correlations are found smaller for cos Gaussian and larger for cosh Gaussian beams. Intensity correlations of cos Gaussian, cosh Gaussian and flat-topped Gaussian beams become larger at large source sizes. Thicker annular beams and flatter flat-topped Gaussian beams show larger intensity correlations. Without generalizing, intensity correlations tend to increase when the link length and the structure constant decrease and the wavelength increases. Our results show that the intensity correlations are not only built up using random medium effects, but also using the diffraction pattern formed at the receiver plane for the specific incidence investigated. As a check point, for all source types and medium parameters, our evaluations indicate that intensity correlations approach zero at sufficiently large diagonal distances.     

Intensity correlations in resonance fluorescence excited by intense incoherent fields

A general rigorous theory of the intensity correlations in resonance fluorescence excited by markovian incoherent fields of arbitrary bandwidth and average intensity is presented. Both single and many independent two-level atom fluorescence are considered.     

Intensity correlations in a coherently prepared Rb vapor in a magnetic field

We have studied the intensity correlations between two orthogonally linearly polarized components of a laser field propagating through a resonant atomic medium. These experiments have been performed in a rubidium atomic vapor. We observe that the correlations between the orthogonally polarized components of the laser beam are maximal in the absence of a magnetic field. The magnitude of the correlations depends on the applied magnetic field, and the magnitude first decreases and then increases with increasing magnetic field. Minimal correlations and maximal rotation angles are observed at the same magnetic fields. The width of the correlation function is directly proportional to the excited state lifetime and inversely proportional to the Rabi frequency of laser field.     

Doppler velocimetry in a supersonic jet by use of frequency-modulated filtered light scattering

A new nonintrusive velocimetry diagnostic that combines the sensitivity of frequency-modulated (FM) absorption spectroscopy techniques and the spectral discrimination afforded by atomic-vapor absorption filters is presented. Doppler-shifted light from a FM Ti:sapphire laser scattered from a supersonic flow is imaged through a potassium-vapor cell and is detected by FM spectroscopy. The difference between the potassium resonance frequency and the laser frequency when the scattered light is in resonance is the flow-induced Doppler shift.     

Intensity and coherence properties of light in oceanic turbulence

Using the Rytov method and Belen'kii and Mironov's method of effective beam parameters for strong turbulence regimes, the intensity and coherence properties of a Gaussian beam propagating through the clear-water turbulent ocean are explored. The refractive index fluctuations are described by a recently developed power spectrum combining the effects from both temperature and salinity. Due to the complicated nature of the oceanic turbulence spectrum, the analysis is restricted to numerical computations.     

Transmission of quantum correlations of light into atoms

JETP Letters - The interaction between two broadband modes of a parametric source of light and two atoms located at different positions has been considered. As follows from the obtained Bell...     

Quantum noise frequency correlations of multiply scattered light

Frequency correlations in multiply scattered light that are present in quantum fluctuations are investigated. The speckle correlations for quantum and classical noise are compared and are found to depend markedly differently on optical frequency, which was confirmed in a recent experiment. Furthermore, novel mesoscopic correlations are predicted that depend on the photon statistics of the incoming light.     

Intensity modulation of light by light in a periodically poled MgO-doped lithium niobate crystal

In this Letter, we investigate a method for controlling the intensity of a light by another light in a periodically poled MgO-doped lithium niobate(PPMgLN) crystal with a transverse applied external electric field. The power of the emergent light can be modulated by the power ratio of the incident ordinary and extraordinary beams. The light intensity control is experimentally demonstrated by the Mach–Zehnder interference configuration, and the results are in good agreement with the theoretical predictions.     

Transmission of quantum correlations of light into atoms

The interaction between two broadband modes of a parametric source of light and two atoms located at different positions has been considered. As follows from the obtained Bell inequalities for light and atoms, quantum correlations of modes, which are caused by the nonlocality of the state of the source, are completely transmitted into atoms. The system under consideration can be used as a quantum channel where information is encoded in nonorthogonal states by modulating the intensity of a pump wave. The channel capacity has been calculated, which is determined by the Helstrom limit.