Method for generating spatiotemporal coherency vortices and spatiotemporal dislocation curves.

A simple method for designing spatiotemporal coherency vortices (STCVs) and spatiotemporal dislocation curves (STDCs) is introduced by means of coherent-mode representation and Fourier transforms. A partially coherent pulsed beam is represented by an incoherent superposition of a Gaussian and a Hermite-Gaussian pulsed beam with different waist positions. It well demonstrates that there exist STCVs and STDCs in the space-time plane.

Source coherence-induced control of spatiotemporal coherency vortices.

A novel method to achieve the coherence control of spatiotemporal coherency vortices of spatially and temporally partially coherent pulsed vortex (STPCPV) beams is proposed. The influence of spatial and temporal coherence of the source on the phase distributions and the positions of spatiotemporal coherency vortices of the STPCPV beams propagating through fused silica is investigated in detail, for the first time to our knowledge. It is found that the coherence width and the coherence time of the incident beam can be regarded as a perfect tool for controlling the phase distribution and position of a spatiotemporal coherency vortex.

Propagation of Gaussian Schell-model beams through a jet engine exhaust.

Theoretical predictions of light beam interactions with jet engine exhaust are of importance for optimization of various optical systems, including LIDARs, imagers and communication links operating in the vicinity of aircrafts and marine vessels. Here we extend the analysis previously carried out for coherent laser beams propagating in jet engine exhaust, to the broad class of Gaussian Schell-Model (GSM) beams, being capable of treating any degree of coherence in addition to size and radius of curvature. The analytical formulas for the spectral density (SD) and the spectral degree of coherence (DOC) of the GSM beam are obtained and analyzed on passage through a typical jet engine exhaust region.

Self-focusing of a partially coherent beam with circular coherence.

In a recent publication [Opt. Lett.42, 1512 (2017)OPLEDP0146-959210.

Position modulation with random pulses.

A new class of sources generating ensemble of random pulses is introduced based on superposition of the mutual coherence functions of several Multi-Gaussian Schell-model sources that separately are capable of shaping the propagating pulse's average intensity into flat profiles with adjustable duration and edge sharpness. Under certain conditions that we discuss in detail such superposition allows for production of a pulse ensemble that after a sufficiently long propagation distance in a dispersive medium reshapes its average intensity from an arbitrary initial profile to a train whose parts have flat intensities of different levels and durations and can be either temporarily separated or adjacent.

Diffraction of cosine-Gaussian-correlated Schell-model beams.

The expression of spectral density of cosine-Gaussian-correlated Schell-model (CGSM) beams diffracted by an aperture is derived, and used to study the changes in the spectral density distribution of CGSM beams upon propagation, where the effect of aperture diffraction is emphasized. It is shown that, comparing with that of GSM beams, the spectral density distribution of CGSM beams diffracted by an aperture has dip and shows dark hollow intensity distribution when the order-parameter n is big enough. The central intensity increases with increasing truncation parameter of aperture.

Cosine-Gaussian correlated Schell-model pulsed beams.

A new class of partially coherent pulses of Schell type with cosine-Gaussian temporal degree of coherence is introduced. Such waves are termed the Cosine-Gaussian Schell-model (CGSM) pulses. The analytic expression for the temporal mutual coherence function of the CGSM pulse in dispersive media is derived and used to study the evolution of its intensity distribution and its temporal degree of coherence.

Scattering-induced changes in the degree of polarization of a stochastic electromagnetic plane-wave pulse.

The scattering of a stochastic electromagnetic plane-wave pulse on a deterministic spherical medium is investigated. An analytical formula for the degree of polarization (DOP) of the scattered field in the far zone is derived. Letting pulse duration T(0) → ∞, our formula can be applied to study the scattering of a stationary stochastic electromagnetic light wave.

Scattering-induced changes in the temporal coherence length and the pulse duration of a partially coherent plane-wave pulse.

The scattering of a partially coherent plane-wave pulse on a Gaussian-correlated, quasi-homogeneous random medium is investigated. The analytical expressions for the temporal coherence length and the pulse duration of the scattered field are derived. We demonstrate that the scattering-induced changes in the temporal coherence length and the pulse duration may be used to determine the correlation function of the scattering potential of the medium.

Phase singularities and spectral changes of spectrally partially coherent higher-order Bessel-Gauss pulsed beams.

Phase singularities and spectral changes of spectrally partially coherent higher-order Bessel-Gauss pulsed beams in free-space propagation are studied, and the analytical expressions for the spectral degree of coherence and spectrum are derived. It is shown that there always exists an optical vortex at the center of the beam and the topological charge is conserved during the propagation. Some circular edge dislocations appear and the spectrum changes on propagation.

Effects of astigmatism on spectra, coherence and polarization of stochastic electromagnetic beams passing through an astigmatic optical system.

Analytical formulas for the cross-spectral density matrix of stochastic electromagnetic Gaussian Schell-model (EGSM) beams passing through an astigmatic optical system are derived. We show both analytically and by numerical examples the effects of astigmatism on spectra, coherence and polarization of stochastic electromagnetic EGSM beams propagating through an astigmatic lens. A comparison with the aberration-free case is made, and shows that the astigmatism has significant effect on the spectra, coherence and polarization.

Effect of dispersion on the spectrum of partially coherent beams.

Taking the Gaussian Schell-model (GSM) beam as a typical example of partially coherent beams, the analytical expressions of the spectrum of GSM beams propagating in dispersive media are derived, and the spectral properties are studied in detail. It is shown that, in comparison with propagation in free space and in turbulence, whether or not GSM beams satisfy the scaling law, the normalized spectrum of GSM beams in dispersive media changes on propagation in general, because the dispersive medium affects different spectral components differently. As compared with the free-space propagation, for the scaling-law GSM beams the dispersion results in spectrum change, and for the nonscaling-law GSM beams the dispersion gives rise to a further increase in spectral changes.