The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yangjian Cai - One of the best experts on this subject based on the ideXlab platform.
-
Nonparaxial Propagation Properties of Specially Correlated Radially Polarized Beams in Free Space
MDPI AG, 2019Co-Authors: Lina Guo, Yiming Dong, Yahong Chen, Li Chen, Rong Lin, Minghui Zhang, Yangjian CaiAbstract:A specially correlated radially polarized (SCRP) beam with unusual physical properties on propagation in the paraxial regime was introduced and generated recently. In this paper, we extend the paraxial propagation of an SCRP beam to the nonparaxial regime. The closed-form 3 × 3 Cross-Spectral Density matrix of a nonparaxial SCRP beam propagating in free space is derived with the aid of the generalized Rayleigh–Sommerfeld diffraction integral. The statistical properties, such as average intensity, degree of polarization, and spectral degree of coherence, are studied comparatively for the nonparaxial SCRP beam and the partially coherent radially polarized (PCRP) beam with a conventional Gaussian–Schell-model correlation function. It is found that the nonparaxial properties of an SCRP beam are strikingly different from those of a PCRP beam. These nonparaxial properties are closely related to the correlation functions and the beam waist width. Our results may find potential applications in beam shaping and optical trapping in nonparaxial systems
-
splitting and combining properties of an elegant hermite gaussian correlated schell model beam in kolmogorov and non kolmogorov turbulence
Optics Express, 2015Co-Authors: Yahong Chen, Lin Liu, Xianlong Liu, Yangjian CaiAbstract:Elegant Hermite-Gaussian correlated Schell-model (EHGCSM) beam was introduced in theory and generated in experiment just recently [Phys. Rev. A 91, 013823 (2015)]. In this paper, we study the propagation properties of an EHGCSM beam in turbulent atmosphere with the help of the extended Huygens-Fresnel integral. Analytical expressions for the Cross-Spectral Density and the propagation factors of an EHGCSM beam propagating in turbulent atmosphere are derived. The statistical properties, such as the spectral intensity, the spectral degree of coherence and the propagation factors, of an EHGCSM beam in Kolmogorov and non-Kolmogorov turbulence are illustrated numerically. It is found that an EHGCSM beam exhibits splitting and combing properties in turbulent atmosphere, and an EHGCSM beam with large mode orders is less affected by turbulence than an EHGCSM beam with small mode orders or a Gaussian Schell-model beam or a Gaussian beam, which will be useful in free-space optical communications.
-
multi gaussian schell model vortex beam
Physics Letters A, 2014Co-Authors: Yongtao Zhang, Lin Liu, Chengliang Zhao, Yangjian CaiAbstract:Abstract Multi-Gaussian Schell-model (MGSM) beam was introduced recently (Sahin and Korotkova, 2012 [34] , and Korotkova et al., 2012 [35] ). In this paper, multi-Gaussian Schell-model vortex (MGSMV) beam is introduced as a natural extension of MGSM beam. The explicit expression for the Cross-Spectral Density of a MGSMV beam propagating through a stigmatic ABCD optical system is derived and the focusing properties of a MGSMV beam are studied in detail. It is found that we can shape the focused beam profile by varying the initial beam parameters, which will be useful in material thermal processing and particle trapping.
-
statistical properties of a nonparaxial cylindrical vector partially coherent field in free space
Optics Express, 2012Co-Authors: Yiming Dong, Chengliang Zhao, Fanlong Feng, Yahong Chen, Yangjian CaiAbstract:Analytical nonparaxial propagation formula for the Cross-Spectral Density matrix of a cylindrical vector partially coherent beam in free space is derived based on the generalized Raleigh-Sommerfeld diffraction integrals. Statistical properties, such as average intensity, degree of polarization and degree of coherence, of a nonparaxial cylindrical vector partially coherent field are illustrated numerically, and compared with that of a paraxial cylindrical vector partially coherent beam. It is found that the statistical properties of a nonparaxial cylindrical vector partially coherent field are much different from that of a paraxial cylindrical vector partially coherent beam, and are closely determined by the initial beam width and correlation coefficients. Our results will be useful for modulating the properties of a nonparaxial cylindrical vector partially coherent field.
-
active laser radar systems with stochastic electromagnetic beams in turbulent atmosphere
Optics Express, 2008Co-Authors: Yangjian Cai, Olga Korotkova, Halil T Eyyuboglu, Yahya BaykalAbstract:Propagation of stochastic electromagnetic beams through paraxial ABCD optical systems operating through turbulent atmosphere is investigated with the help of the ABCD matrices and the generalized Huygens-Fresnel integral. In particular, the analytic formula is derived for the Cross-Spectral Density matrix of an electromagnetic Gaussian Schell-model (EGSM) beam. We applied our analysis for the ABCD system with a single lens located on the propagation path, representing, in a particular case, the unfolded double-pass propagation scenario of active laser radar. Through a number of numerical examples we investigated the effect of local turbulence strength and lens' parameters on spectral, coherence and polarization properties of the EGSM beam.
Emil Wolf - One of the best experts on this subject based on the ideXlab platform.
-
cross spectral Density matrix of blackbody radiation
Frontiers in Optics, 2008Co-Authors: Mayukh Lahiri, Emil WolfAbstract:Important concept in theory of stochastic light beams is Cross-Spectral Density matrix. We derive explicit expression for the Cross-Spectral Density matrix in the far zone of a beam generated by blackbody source.
-
the cross spectral Density matrix of a planar electromagnetic stochastic source as a correlation matrix
Optics Communications, 2008Co-Authors: Miguel A Alonso, Emil WolfAbstract:It is shown that the Cross-Spectral Density matrix of a planar, secondary, stochastic electromagnetic source is a correlation matrix. Unlike a previously published proof of this result, our derivation is based on the solution of two uncoupled, rather than two coupled, integral equations.
-
changes in the spectrum in the spectral degree of polarization and in the spectral degree of coherence of a partially coherent beam propagating through a gradient index fiber
Journal of The Optical Society of America A-optics Image Science and Vision, 2006Co-Authors: Hema Roychowdhury, Govind P Agrawal, Emil WolfAbstract:Expressions are derived for the Cross-Spectral Density matrix of an electromagnetic Gaussian Schell-model beam propagating through a paraxial ABCD system. Using the recently developed unified theory of coherence and polarization of electromagnetic beams and the ABCD matrix for gradient-index fibers, we study the changes of the spectral Density, of the spectral degree of polarization, and of the spectral degree of coherence of such a beam as it travels through the fiber. Effects of material dispersion are also considered.
-
beam conditions for radiation generated by an electromagnetic gaussian schell model source
Optics Letters, 2004Co-Authors: Olga Korotkova, Mohamed Salem, Emil WolfAbstract:It was shown recently that the basic properties of a fluctuating electromagnetic beam can be derived from knowledge of a 2 x 2 Cross-Spectral Density matrix of the electric field in the source plane. However, not every such matrix represents a source that will generate a beamlike field. We derive conditions that the matrix must satisfy for the source to generate an electromagnetic Gaussian Schell-model beam.
-
determination of the electric cross spectral Density matrix of a random electromagnetic beam
Optics Communications, 2003Co-Authors: Hema Roychowdhury, Emil WolfAbstract:Abstract It has been shown in a recent publication that in order to calculate the changes which the degree of polarization, the degree of coherence and the spectrum of a random electromagnetic beam undergo as the beam propagates, it is necessary to know the 2 × 2 Cross-Spectral Density matrix of the fluctuating electric field. In this paper, a procedure is described for measuring the four elements of this matrix, with the help of two polarizers and a rotator. The procedure makes use of the Young interference experiment and the recently derived spectral interference law for such beams.
Zhangrong Mei - One of the best experts on this subject based on the ideXlab platform.
-
propagation properties of the rectangular multi gaussian schell model beams in uniaxial crystals orthogonal to the optical axis
IEEE Photonics Journal, 2017Co-Authors: Yonghua Mao, Zhangrong MeiAbstract:A stochastic beam generated by a recently introduced source of Schell type with rectangular multi-Gaussian spectral degree of coherence is shown to posses interesting novel features on propagation in uniaxial crystals. The analytical expression for the Cross-Spectral Density function of the rectangular multi-Gaussian Schell-model (RMGSM) beams propagating in uniaxial crystals orthogonal to the optical axis is derived. With the help of the derived formula, the evolution properties of the spectral Density, the effective beam width, and the spectral degree of coherence of the RMGSM beams in a uniaxial crystal are investigated in detail. It is shown that the evolution properties of an RMGSM beam in uniaxial crystal are much different from its evolution properties in free space, and the propagation properties of the RMGSM beams in uniaxial crystals are closely related to the initial beam parameters (beam index M and spatial coherence length) and the parameters of the uniaxial crystals (the ratio of extraordinary and ordinary refractive indices). The results demonstrate the potential of uniaxial crystals for modulating the properties of the RMGSM beams.
-
cosine gaussian schell model sources
Optics Letters, 2013Co-Authors: Zhangrong Mei, Olga KorotkovaAbstract:We introduce a new class of partially coherent sources of Schell type with cosine-Gaussian spectral degree of coherence and confirm that such sources are physically genuine. Further, we derive the expression for the Cross-Spectral Density function of a beam generated by the novel source propagating in free space and analyze the evolution of the spectral Density and the spectral degree of coherence. It is shown that at sufficiently large distances from the source the degree of coherence of the propagating beam assumes Gaussian shape while the spectral Density takes on the dark-hollow profile.
Olga Korotkova - One of the best experts on this subject based on the ideXlab platform.
-
cosine gaussian schell model sources
Optics Letters, 2013Co-Authors: Zhangrong Mei, Olga KorotkovaAbstract:We introduce a new class of partially coherent sources of Schell type with cosine-Gaussian spectral degree of coherence and confirm that such sources are physically genuine. Further, we derive the expression for the Cross-Spectral Density function of a beam generated by the novel source propagating in free space and analyze the evolution of the spectral Density and the spectral degree of coherence. It is shown that at sufficiently large distances from the source the degree of coherence of the propagating beam assumes Gaussian shape while the spectral Density takes on the dark-hollow profile.
-
active laser radar systems with stochastic electromagnetic beams in turbulent atmosphere
Optics Express, 2008Co-Authors: Yangjian Cai, Olga Korotkova, Halil T Eyyuboglu, Yahya BaykalAbstract:Propagation of stochastic electromagnetic beams through paraxial ABCD optical systems operating through turbulent atmosphere is investigated with the help of the ABCD matrices and the generalized Huygens-Fresnel integral. In particular, the analytic formula is derived for the Cross-Spectral Density matrix of an electromagnetic Gaussian Schell-model (EGSM) beam. We applied our analysis for the ABCD system with a single lens located on the propagation path, representing, in a particular case, the unfolded double-pass propagation scenario of active laser radar. Through a number of numerical examples we investigated the effect of local turbulence strength and lens' parameters on spectral, coherence and polarization properties of the EGSM beam.
-
angular spectrum representation for the propagation of arbitrary coherent and partially coherent beams through atmospheric turbulence
Journal of The Optical Society of America A-optics Image Science and Vision, 2007Co-Authors: Greg Gbur, Olga KorotkovaAbstract:An angular spectrum representation is applied for a description of statistical properties of arbitrary beamlike fields propagating through atmospheric turbulence. The Rytov theory is used for the characterization of the perturbation of the field by the atmosphere. In particular, we derive expressions for the Cross-Spectral Density of a coherent and a partially coherent beam of arbitrary type in the case when the power spectrum of atmospheric fluctuations is described by the von Karman model. We illustrate the method by applying it to the propagation of several model beams through the atmosphere.
-
angular spectrum representation for propagation of random electromagnetic beams in a turbulent atmosphere
Journal of The Optical Society of America A-optics Image Science and Vision, 2007Co-Authors: Olga Korotkova, Greg GburAbstract:The combination of an angular spectrum representation (in the space-frequency domain) and the second-order Rytov perturbation theory is applied for description of the second-order statistical properties of arbitrary (coherent and partially coherent) stochastic electromagnetic beamlike fields that propagate in a turbulent atmosphere. In particular, we derive the expressions for the elements of the Cross-Spectral Density matrix of the beam, from which its spectral, coherence, and polarization properties can be found. We illustrate the method by applying it to the propagation of several electromagnetic model beams through the atmosphere.
-
beam conditions for radiation generated by an electromagnetic gaussian schell model source
Optics Letters, 2004Co-Authors: Olga Korotkova, Mohamed Salem, Emil WolfAbstract:It was shown recently that the basic properties of a fluctuating electromagnetic beam can be derived from knowledge of a 2 x 2 Cross-Spectral Density matrix of the electric field in the source plane. However, not every such matrix represents a source that will generate a beamlike field. We derive conditions that the matrix must satisfy for the source to generate an electromagnetic Gaussian Schell-model beam.
Oscar G Rodriguezherrera - One of the best experts on this subject based on the ideXlab platform.
-
generalized van cittert zernike theorem for the cross spectral Density matrix of quasi homogeneous planar electromagnetic sources
Frontiers in Optics, 2012Co-Authors: Oscar G RodriguezherreraAbstract:We present a generalized van Cittert-Zernike theorem for the Cross-Spectral Density matrix of quasi-homogeneous planar electromagnetic sources. An example of the generation of a beam with interesting polarization and spatial coherence properties is discussed. This example was obtained by choosing the appropriate spectral Density distribution of the source. We found that, under certain conditions, a quasi-homogeneous, polarized source may produce a beam in the far-field that is unpolarized in the typical one-point sense but polarized in the two-point mutual polarization sense. © 2012 Optical Society of America
-
generalized van cittert zernike theorem for the cross spectral Density matrix of quasi homogeneous planar electromagnetic sources
Journal of The Optical Society of America A-optics Image Science and Vision, 2012Co-Authors: Oscar G RodriguezherreraAbstract:A generalized van Cittert–Zernike theorem for the Cross-Spectral Density matrix of quasi-homogeneous planar electromagnetic sources is introduced. We present theoretical examples of using this theorem to generate fields with interesting polarization and spatial coherence properties by choosing the appropriate spectral Density distribution of the source. We found that under certain conditions, a quasi-homogeneous, polarized source may produce a beam in the far field that is unpolarized in the typical one-point sense but polarized in the two-point, mutual polarization sense.