Boivin L P
Appl Opt. 1976 May 1;15(5):1204-9. doi: 10.1364/AO.15.001204.
The diffraction corrections associated with a circular aperture in the case of an extended source and a detector located in the fully illuminated region have been calculated in 1972 by Steel, De, and Bell. We have shown recently that the intensity distribution formula that they have used is not accurate in the central region of the diffraction pattern and greatly underestimates the diffraction corrections associated with a point source. In this paper, we take up the case of an extended source; we have followed Steel et al.'s method of calculation, but have used an intensity distribution which we have shown to be valid in the central region. We show that in the case of complex radiation, the variation of the diffraction correction with the source radius rho takes a very simple form: the diffraction correction remains approximately constant as rho increases, until the source and detector subtend equal angles at the center of the aperture; if rho is increased further, the diffraction correction decreses linearly with 1/rho over a certain range of rho. Experimental results are presented that confirm these theoretical predictions.
1972年，斯蒂尔、德和贝尔计算了在扩展光源和位于完全照明区域的探测器情况下与圆形孔径相关的衍射校正。我们最近表明，他们所使用的强度分布公式在衍射图样的中心区域并不准确，并且极大地低估了与点光源相关的衍射校正。在本文中，我们探讨扩展光源的情况；我们采用了斯蒂尔等人的计算方法，但使用了一个我们已证明在中心区域有效的强度分布。我们表明，在复合辐射的情况下，衍射校正随光源半径ρ的变化呈现出非常简单的形式：随着ρ增大，衍射校正大致保持恒定，直到光源和探测器在孔径中心所张的角度相等；如果ρ进一步增大，在ρ的一定范围内，衍射校正随1/ρ线性减小。给出了证实这些理论预测的实验结果。
