Tanaka K, Sakamoto K, Tanaka T, Taguchi M
Appl Opt. 1995 Oct 1;34(28):6332-6. doi: 10.1364/AO.34.006332.
Side lobes can be suppressed by means of a suitable filter across an aperture. This method is well known in optics as apodization. To obtain the desired field, we approximate it by a Gaussian field. Then it is transformed to the transmittance function of the filter. The field and the transmittance function are Fourier-transform pairs. In general, the Fourier transform of an arbitrary function extends infinitely. This means that we cannot obtain an exact transmittance function of the filter that gives the desired diffraction pattern. We discuss a transmittance function that approximates a specified diffraction pattern. We express the Fraunhofer diffraction pattern as a sum of beam-mode functions and approximate it by the first term. Then, by using the Fourier transform, we can obtain the transmittance function. The diffraction field through the truncated filter is also obtained, and the effect of truncation is discussed.
旁瓣可以通过在孔径上使用合适的滤波器来抑制。这种方法在光学中作为切趾术是众所周知的。为了获得所需的场，我们用高斯场对其进行近似。然后将其转换为滤波器的透过率函数。场和透过率函数是傅里叶变换对。一般来说，任意函数的傅里叶变换会无限延伸。这意味着我们无法获得能给出所需衍射图样的滤波器的精确透过率函数。我们讨论一种近似指定衍射图样的透过率函数。我们将夫琅禾费衍射图样表示为光束模式函数的和，并通过第一项对其进行近似。然后，通过使用傅里叶变换，我们可以获得透过率函数。还得到了通过截断滤波器的衍射场，并讨论了截断的影响。
