| 1. |
- Cai, Yangjian, et al.
(författare)
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Analytical formula for a decentered elliptical Gaussian beam propagating in a turbulent atmosphere
- 2007
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 271:2, s. 509-516
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Tidskriftsartikel (refereegranskat)abstract
- Analytical formulas for the average intensity and decentered parameter of a decentered elliptical Gaussian beam (DEGB) propagating in a turbulent atmosphere are derived in a tensor form. The propagation properties of a DEGB in a turbulent atmosphere are investigated in detail, and found to be different from that in free space. Furthermore, as an application example, we investigate the propagation of a decentered elliptical flat-topped beam (DEFB) by expressing its electric field as a finite sum of DEGBs in a turbulent atmosphere. The properties of a DEGB or a DEFB in a turbulent atmosphere are closely related with the beam's parameters and the structure constant of the turbulent atmosphere.
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| 2. |
- Cai, Yangjian, et al.
(författare)
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Average intensity and spreading of an elliptical Gaussian beam propagating in a turbulent atmosphere
- 2006
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 31:5, s. 568-570
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Tidskriftsartikel (refereegranskat)abstract
- An analytical formula for the average intensity of an elliptical Gaussian beam (EGB) propagating in a turbulent atmosphere is derived. The spreading properties of an EGB in a turbulent atmosphere are studied. It is found that an EGB will eventually become a circular Gaussian beam in a turbulent atmosphere. This interesting phenomenon is quite different from the propagation of an EGB in free space. The evolution properties are closely related to the parameters of the beam and the turbulent atmosphere
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| 3. |
- Cai, Yangjian, et al.
(författare)
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Coherent and partially coherent dark hollow beams with rectangular symmetry and paraxial propagation properties
- 2006
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 23:7, s. 1398-1407
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Tidskriftsartikel (refereegranskat)abstract
- A theoretical model is proposed to describe coherent dark hollow beams (DHBs) with rectangular symmetry. The electric field of a coherent rectangular DHB is expressed as a superposition of a series of the electric field of a finite series of fundamental Gaussian beams. Analytical propagation formulas for a coherent rectangular DHB passing through paraxial optical systems are derived in a tensor form. Furthermore, for the more general case, we propose a theoretical model to describe a partially coherent rectangular DHB. Analytical propagation formulas for a partially coherent rectangular DHB passing through paraxial optical systems are derived. The beam propagation factor (M-2 factor) for both coherent and partially coherent rectangular DHBs are studied. Numerical examples are given by using the derived formulas. Our models and method provide an effective way to describe and treat the propagation of coherent and partially coherent rectangular DHBs.
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| 4. |
- Cai, Yangjian, et al.
(författare)
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Coincidence fractional Fourier transform implemented with partially coherent light radiation
- 2005
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Ingår i: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION. - 1084-7529. ; 22:9, s. 1798-1804
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Tidskriftsartikel (refereegranskat)abstract
- We introduce the coincidence fractional Fourier transform (FRT) implemented with incoherent and partially coherent light radiation. Optical systems for implementing the coincidence FRT are designed. The results show that the visibility and quality of the coincidence FRT of an object are closely related to the light source's transverse size, coherence, and spectral width. As an example, we numerically study the coincidence FRT of a single slit. (c) 2005 Optical Society of America.
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| 5. |
- Cai, Yangjian, et al.
(författare)
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Coincidence subwavelength fractional Fourier transform
- 2006
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Ingår i: Optical Society of America. Journal A. - 1084-7529 .- 1520-8532. ; 23:4, s. 835-841
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Tidskriftsartikel (refereegranskat)abstract
- The coincidence subwavelength fractional Fourier transforms (FRTs) with entangled photon pairs and incoherent light radiation are introduced as an extension of the recently introduced coincidence FRT. Optical systems for implementing the coincidence subwavelength FRTs are designed. The width of the coincidence subwavelength FRT pattern is two times narrower than the width of the coincidence FRT. The coincidence subwavelength FRT with partially coherent light radiation is also studied numerically. Differences between the coincidence subwavelength FRT with entangled photon pairs and that with incoherent light radiation are discussed.
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| 6. |
- Cai, Yangjian, et al.
(författare)
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Lensless imaging with partially coherent light
- 2007
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 32:3, s. 205-207
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Tidskriftsartikel (refereegranskat)abstract
- Based on the fourth-order correlation of light, lensless imaging with incoherent or partially coherent light is investigated theoretically by use of classical optical coherence theory. A novel lensless optical system for implementing imaging is proposed. The visibility and quality of the image are influenced by the coherence and transverse size of the light source. The results suggest useful imaging applications in x-ray, gamma-ray, or other wavelengths where no effective lens is available, and they have potential applications in optical metrology and holography.
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| 7. |
- Cai, Yangjian, et al.
(författare)
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Lensless optical implementation of the coincidence fractional Fourier transform
- 2006
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 31:15, s. 2278-2280
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Tidskriftsartikel (refereegranskat)abstract
- A lensless optical system for implementing the coincidence fractional Fourier transform (FRT) is proposed. The conditions for the lensless optical system to implement the coincidence FRT with incoherent light and entangled photon pairs are discussed. The results offer a novel scheme for FRTs and thus suggest useful applications.
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| 8. |
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| 9. |
- Cai, Yangjian, et al.
(författare)
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Propagation of a hollow Gaussian beam through a paraxial misaligned optical system
- 2006
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 265:2, s. 607-615
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Tidskriftsartikel (refereegranskat)abstract
- Based on the generalized diffraction integral formula for treating the propagation of a laser beam through a paraxial misaligned optical system in the cylindrical coordinate system, we obtain an analytical formula for a hollow Gaussian beam passing through a paraxial misaligned optical system. Furthermore, we also obtain the approximate analytical formula for a hollow Gaussian beam passing through a paraxial circularly apertured misaligned optical system by expanding the hard aperture function into a finite sum of complex Gaussian functions. As a numerical example, the propagation properties a hollow Gaussian beam through a misaligned thin lens are studied numerically.
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| 10. |
- Cai, Yangjian, et al.
(författare)
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Propagation of a partially coherent twisted anisotropic Gaussian Schell-model beam in a turbulent atmosphere
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:4
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Tidskriftsartikel (refereegranskat)abstract
- Analytical formulas are derived for the propagation of a partially coherent twisted anisotropic Gaussian Schell-model (TAGSM) beam in a turbulent atmosphere. Propagation properties of a TAGSM beam in a turbulent atmosphere are investigated in detail. It is found that a TAGSM beam will become a circular beam in a turbulent atmosphere, and low coherence and larger twist have an effect of anticircularization of the beam spot. The beam spot spreads more rapidly for lower coherence, larger twist, or stronger turbulence.
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