Imaging system using optical diffraction spectrum - varies optical path length to adjust radius of imaging zone

摘要

The system allows the image of an object to be recorded via its optical diffraction spectrum, e.g. a Fraunhofer diffraction image, a power spectrum, a Fourier spectrum or a Wiener spectrum. The imaging is effected over a selected annular zone using a multiple interference effect, with the radius of this zone adjusted by varying the length of the optical path between the object and the detector system. This variation of the optical path may be effected by piezoelectrically shifting a mirror arranged in the optical path. Pref. the optical path for the interference beam is a whole multiple of the resonation wavelength of the laser source used to illuminate the object.