Investigate Propagation Properties Of Partially Coherent And Partially Polarized Beam Propagating In Turbulent Atmosphere By The Tensor Method

The coherence, polarization and spectral properties of light field are main topics in the laser optics, which play an important role in development of the modern optics theory and laser technologies. Starting from the propagation law of partially coherent light, I present in this dissertation the research results on the propagation and the spectral characteristics of the partially coherent light and the partially coherent partially polarized light propagating in turbulent atmosphere by use of convenient and effective tensor method. The main works of this paper are lasted as follows:(1)Start from the propagation law of the cross-spectral density function in the space-frequency domain, the spectral changes of the partially coherent twist anisotropic Gaussian-Schell model(TAGSM) beam and elliptical Gaussian beam(EGB) propagating in turbulent atmosphere are investigated. Nummerical calculations and analysis shows that: the spectral changes of pratially coherent beam which dosen't follow "the scalling low" propagating in turbulent atmosphere are induced by the coherence of the source beam and the diffraction of the turbulent atmosphere; we can modulate the value of the relative spectral changes and the spectral switch through modulating the degree of twist property, the coherence, the spot width of partially coherent beams. The results obtained in this paper would be useful for spectral experiments and the high-precision spectral measurements. The spectral changes of partially coherent beams propagating in turbulent atmosphere would be hopefully applied to the optical interconnection and optical communication, etc.Takeing into the consideration of the technology application, the propagation properties of the beams parameters of TAGSM beam, the decentered parameter of decentered TAGSM beam and partially coherent dark hollow beams(DHBs) propagating in turbulent atmosphere have been investigated.(2)Analytical expressions of the radial partially coherent flat-topped beam (FTB) array propagating in turbulent atmosphere are derived firstly, where the correlated superposition and uncorrelated superposition are considered. Detailed numerical calculations illustrate the distribution of normalized average intensity and the the modulus of the complex degree of coherence of radial FTB array propagating in turbulent atmosphere. It is shown that the atmospheric turbulence and the correlation of each beamlet are two main factors which affect the propagation of array beams. Because of the influence of the turbulent atmosphere, the normalized average intensity distribution of the correlated and uncorrelated case propagating in turbulent atmosphere tends to Gaussian shape;the distribution of the modulus of the complex degree of coherence of radial FTB array beam starts and ends as Gaussian distribution which resembles the average intensity profile. The spatial coherence of correlated or uncorrelated radial FTB array becomes worse with increasing z in turbulent atmosphere. The results obtained would be useful for partially coherent array beam propagating in atmosphere.(3) Based on the isotropic electromagnetic Gaussian-Schell model beam, we introduced the mathematical physics model of stochastic electromagnetic twist anisotropic Gaussian-Schell model (ETAGSM) beam by use of the tensor method. Based on the unified theory of coherence and polariziation, the analytical propagation expressions for the cross-spectral density matrix of ETAGSM beams with aperture or not propagating in turbulent atmosphere are derived, which permits us to study the spectral properties of ETAGSM beams with aperture or not. Detailed numerical caculations show that:the affection of the aperture on the spectral properties of the stochastic ETAGSM beam is obvious in the near field; while in the far field, the atmospheric turbulence plays an important role; we can modulate the distribution the spectral degree of polarization of stochastic ETAGSM beams propagating in turbulent atmosphere through modulating the parameters of aperture, the twist property and the coherence of the source beams.The results obtained in this paper would be useful for studying the propagation of partially coherent beams and partially polarized beam propagating through turbulent atmosphere. This thesis emphasizes on the research of the theory and of the laser beam propagation in the atmosphere, which experiments are of great importance in the areas of laser radar, laser missile-guidance and communication etc.