Laguerre-Gaussian Schell-model Beam Research Articles

Average intensity and directionality of partially coherent model beams propagating in turbulent ocean.

We studied Gaussian beams with three different partially coherent models, including the Gaussian-Schell model (GSM), Laguerre-Gaussian Schell model (LGSM), and Bessel-Gaussian Schell model (BGSM), propagating through oceanic turbulence. The expressions of average intensity, beam spreading, and beam wander for GSM, LGSM, and BGSM beams in the paraxial channel are derived. We make a contrast for the three models in numerical simulations and find that the GSM beam has smaller spreading than the others, and the LGSM beam needs longer propagation distance to transform into a well-like profile of average intensity than the BGSM beam in the same conditions. The salinity fluctuation has a greater contribution to the wander of LGSM and BGSM beams than that of the temperature fluctuation. Our results can be helpful in the design of an optical wireless communication link operating in oceanic environment.

Laguerre-Gaussian functions and generalized formulation of electromagnetic Gaussian Schell-model sources.

Fourier transform of the combination of Gaussian function and power functions of even exponents 2n(n=0,1,2,…) gives rise to a class of physically realizable electromagnetic sources with correlation properties expressible in terms of Laguerre-Gaussian functions. Relatively simple mathematical expressions of the electromagnetic beams produced by the Laguerre-Gaussian Schell-model sources are given for an investigation of the coherence and polarization properties and the higher-order coherence effect of the correlations between intensity fluctuations in the Laguerre-Gaussian Schell-model beams (Laguerre-GSMB) of any order n. Results obtained are compared numerically with the predictions of the classic electromagnetic Gaussian Schell-model beam that is the lowest-order Laguerre-GSM beams.

Statistical properties of a Laguerre-Gaussian Schell-model beam in turbulent atmosphere

Laguerre-Gaussian Schell-model (LGSM) beam was proposed in theory [Opt. Lett.38, 91 (2013 Opt. Lett.38, 1814 (2013)] just recently. In this paper, we study the propagation of a LGSM beam in turbulent atmosphere. Analytical expressions for the cross-spectral density and the second-order moments of the Wigner distribution function of a LGSM beam in turbulent atmosphere are derived. The statistical properties, such as the degree of coherence and the propagation factor, of a LGSM beam in turbulent atmosphere are studied in detail. It is found that a LGSM beam with larger mode order n is less affected by turbulence than a LGSM beam with smaller mode order n or a GSM beam under certain condition, which will be useful in free-space optical communications.