Unconventional treatment of focal shift
Vokinger, Urs ; Dändliker, René ; Blattner, Peter ; Herzig, Hans-Peter
In: Optics Communications, 1998, vol. 157, no. 1-6, p. 218-224
We present an unconventional approach for the explanation of focal shift behind a lens. It is based on the fact that, within the approximation of Fresnel diffraction, the intensity distributions in the conjugate planes of a lens are equal to their geometrical images. We show that the focus (position of highest intensity) is always shifted towards the lens. The results for a Gaussian beam and a... More
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- We present an unconventional approach for the explanation of focal shift behind a lens. It is based on the fact that, within the approximation of Fresnel diffraction, the intensity distributions in the conjugate planes of a lens are equal to their geometrical images. We show that the focus (position of highest intensity) is always shifted towards the lens. The results for a Gaussian beam and a uniform converging spherical wave are presented.