The Fourier optics (according to Jean Baptiste Joseph Fourier ) is a portion of the optics , in which the propagation of light with the aid of Fourier analysis is examined. Fourier optics take into account the wave nature of light, but neglect z. B. the polarization .
In the far field of the structure, the following applies to the amplitude distribution:
- the distance from the diffractive structure
- the transverse coordinates
- a phase factor.
- the wavelength
The far field is given by the two-dimensional Fourier transform of the field immediately behind the diffractive structure:
Importance of spatial frequencies
A ray from the point in the observation plane to the point in the plane of the diffractive structure includes the following angles with the axis:
Light that is close to the optical axis in the far field corresponds to low spatial frequencies, while light located further out belongs to high spatial frequencies.
Fine structures in the object, i.e. those that change quickly in space, belong to high spatial frequencies; accordingly, coarser structures represent lower spatial frequencies.
- Joseph W. Goodman : Introduction to Fourier optics. 3rd edition. Roberts & Co., Englewood CO 2005, ISBN 0-9747077-2-4 .
- Wolfgang Stößel: Fourier optics. An introduction. With 47 exercises and solutions. Springer, Berlin et al. 1993, ISBN 3-540-53287-0 .