What is meant by Fresnel distance in optics

Asked By reema 70 points N/A Posted on - 10/08/2011

What is meant by Fresnel distance in optics IE diffraction how is it related to the validity of ray optics please do make it simple as I am a beginner?

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Answered By Ealdwine 10 points N/A #89616

What is meant by Fresnel distance in optics

The Fresnel diffraction in optics is expressed by an equation for near field diffraction and it is an approximation of Kirchhoff-Fresnel diffraction which can be employed to the propagation of waves in the near field.

The near field is denoted by the Fresnel number, F of the optical arrangement that can be defined as for a wave incident on an aperture:

where

 is the characteristic size of the aperture

 is the distance of the observation point from the aperture

 is the wavelength of the wave.

The several Fresnel diffraction causes the specular reflection at the nearly placed periodical ridges and this result  may be employed for atomic mirrors.

                    

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• Posted on - 10/11/2011
• Question Category: Internet