Effect of anisotropy on the radius of curvature and Rayleigh range of a general-type partially coherent beam in oceanic turbulence

2020 ◽  
Author(s):  
Xingrong Zheng ◽  
Wenyu Fu
Keyword(s):  
General Type ◽  
Coherent Beam ◽  
Radius Of Curvature ◽  
Oceanic Turbulence ◽  
Partially Coherent ◽  
Rayleigh Range

scholarly journals Ghost Imaging with a Partially Coherent Beam Carrying Twist Phase in a Turbulent Ocean: A Numerical Approach

2019 ◽  
Vol 9 (15) ◽  
pp. 3023 ◽  
Author(s):  
Yonglei Liu ◽  
Xianlong Liu ◽  
Lin Liu ◽  
Fei Wang ◽  
Yuping Zhang ◽  
...  
Keyword(s):  
Numerical Approach ◽  
Coherent Beam ◽  
Ghost Imaging ◽  
Oceanic Turbulence ◽  
Partially Coherent ◽  
Rytov Approximation ◽  
Twist Factor ◽  
Imaging Approach ◽  
Optical Paths

Ghost imaging (GI) is an indirect imaging approach that can retrieve an object’s image even in a harsh environment through measuring the fourth-order correlation function (FOCF) between the signal and idle optical paths. In this paper, we study lensless GI with a partially coherent beam carrying twist phase, i.e., twisted Gaussian Schell-model (TGSM) beam, in the presence of oceanic turbulence. Explicit expression of the FOCF is derived based on the optical coherence theory and Rytov approximation, and the effects of the twist phase and the oceanic turbulence on the quality and visibility of image are investigated in detail through numerical examples. Our results show that the simulated oceanic turbulence strongly affects the GI. The quality of image decreases monotonously with an increase of the strength of turbulence whereas the visibility increases. When the illumination light carries a twist phase, the visibility of the image is improved while the quality of the image is reduced in contrast to those without a twist phase. By properly selecting the strength of the twist phase, the image can still be maintained at an acceptable level of quality with high visibility. Furthermore, it is found that the quality and visibility of the ghost image are less affected by the oceanic turbulence using a TGSM beam with larger twist factor. Our findings will be useful for the application of GI in an oceanic turbulent environment.

scholarly journals Independently Controlling Stochastic Field Realization Magnitude and Phase Statistics for the Construction of Novel Partially Coherent Sources

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 60
Author(s):  
Milo W. Hyde
Keyword(s):  
Coherent Beam ◽  
Optical Field ◽  
Stochastic Field ◽  
Partially Coherent ◽  
Second Moments ◽  
Coherent Beams ◽  
Gaussian Statistics ◽  
Simulated Field ◽  
Gaussian Moment ◽  
Partially Coherent Beams

In this paper, we present a method to independently control the field and irradiance statistics of a partially coherent beam. Prior techniques focus on generating optical field realizations whose ensemble-averaged autocorrelation matches a specified second-order field moment known as the cross-spectral density (CSD) function. Since optical field realizations are assumed to obey Gaussian statistics, these methods do not consider the irradiance moments, as they, by the Gaussian moment theorem, are completely determined by the field’s first and second moments. Our work, by including control over the irradiance statistics (in addition to the CSD function), expands existing synthesis approaches and allows for the design, modeling, and simulation of new partially coherent beams, whose underlying field realizations are not Gaussian distributed. We start with our model for a random optical field realization and then derive expressions relating the ensemble moments of our fields to those of the desired partially coherent beam. We describe in detail how to generate random optical field realizations with the proper statistics. We lastly generate two example partially coherent beams using our method and compare the simulated field and irradiance moments theory to validate our technique.

Shaping the beam profile of a partially coherent beam by a phase aperture

2011 ◽  
Vol 284 (18) ◽  
pp. 4129-4135 ◽  
Author(s):  
Gaofeng Wu ◽  
Yangjian Cai ◽  
Jun Chen
Keyword(s):  
Coherent Beam ◽  
Beam Profile ◽  
Partially Coherent

Analysing the behaviour of partially coherent divergent Gaussian beams propagating through oceanic turbulence

2014 ◽  
Vol 61 (17) ◽  
pp. 1430-1441 ◽  
Author(s):  
M. Yousefi ◽  
F.D. Kashani ◽  
Sh. Golmohammady ◽  
E. Kazemian ◽  
B. Ghafary
Keyword(s):  
Gaussian Beams ◽  
Oceanic Turbulence ◽  
Partially Coherent
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