Study on property of central spot of non-diffracting beams
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School of Mechanical Science and Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
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Corresponding author:
ZHAO Bin, zhaobin63@sohu.com
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Received Date:
2007-05-10
Accepted Date:
2007-09-06
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Abstract
In order to use non-diffracting beams to extend the depth-of-field of optical imaging systems,the variation rules of the central spot of non-diffracting beams were investigated.Based on the theory of Fresnel diffraction,the diffraction patterns were analyzed when the point source was placed in front of focal plane,at focal plane and behind focal plane.Then the radius and intensity calculation formula of the central spot of non-diffracting beams correspond to the distance from the point source to the lens or the distance between the partial coherent point source and the lens,were deduced according to the theory of partial coherent light.Finally,experiments were done by using a red high brightness LED as the quasi-monochromatic light source.The experimental results showed that the radius of the central spot decreased with the increase of the distance from the point source to the lens,and the intensity of the central spot increased with the increasing of the distance from the point source to the lens.The outcome provides stated academic gist to the applications of non-diffracting beams in imaging system.
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References
[1]
|
DURNIN J.Exact solutions for nondiffracting beams I.The scalar theory[J].J O S A,1987,A4(4):651-654. |
[2]
|
LU B D,ZHANG B,CAI B W,et al.The investigation of the diffraction free beam with a finite aperture[J].Chinese Science Bulletin,1994,39(2):125-128(in Chinese). |
[3]
|
GRZEGORZ M,ANDRZEJ K,MICHALM.Diffractive elements forimaging with extended depth of focus[J].Opt Engng,2005,44(5):058001-1-058001-7. |
[4]
|
GRAEME S,NELL M.Efficient generation of nearly diffraction-free beams using an axicon[J].Opt Engng,1992,31(12):2640-2643. |
[5]
|
ZHAO B,LI Zh.Diffraction property of an axicon in oblique illuminate[J].Appl Opt,1998,37(13):2563-2568. |
[6]
|
ANNA T,ZBIGNIEW J,ARI T F.Diffractive axicons in oblique illumination:analysis and experiments and comparison with elliptical axicons[J].Appl Opt,2003,42(1):9-17. |
[7]
|
ZHANG B,LU B D.Analyzing the propagation properties of diffraction-free beams[J].Laser Technology,1996,20(1):14-19(in Chinese). |
[8]
|
BORN M,WOLF E.Principles of optics[M].7th ed.New York:Cambridge University Press,1999:888-890. |
[9]
|
STAMNES J.Waves in focal regions[M].London:Hilger,1986:91-135. |
[10]
|
LU N G.Fourier optics[M].2th ed.Beijing:China Machine Press,2006:182-223(in Chinese). |
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Proportional views
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