IMAGING WITH COHERENT FIELDS.
ILLINOIS UNIV URBANA ANTENNA LAB
Pagination or Media Count:
A diffraction theory of imaging is presented which is free of any apriori constraint on the wavelength and as such serves as a basis for imaging not only at optics, but microwaves and acoustics as well. The paper presents analytical procedures for producing real and virtual images and relates them where possible to physical systems such as holography. The solution to the exterior reconstruction problem and thus the virtual imaging problem is obtained by an application of Huygens principle. So, when the recording surface completely encloses the object, an exact virtual image can be obtained analytically or experimentally for a recording surface of arbitrary shape. The interior reconstruction problem, better known in diffraction theory as the inverse scattering problem, is, in general, more difficult than the exterior problem. It is found that unlike the virtual imaging case, the procedure for reconstructing the real image is a function of the recording surface shape. Furthermore, by explicit consideration of the visible and invisible spectral components of the scattered fields, it is shown that there exist no physical system capable of producing an exact real image. Indeed conventional holography obtains the real image only when the recording is planar and then it only reconstructs essentially the visible spectral components of the real images - even if the recording surface is of infinite extent. Author
- Lasers and Masers