INTERFERENCE PATTERN OF THE WAVE FIELD OF TWO SOURCES IN THE NEAR FIELD OF OBSERVATION.

The paper considers the problem of an approximate wave field in the so-called near, middle and far zones of observation. The possibility of introducing a more accurate than the Fresnel approximation, the so-called quasi-exact approximation, is indicated. For the interference problem usually considered in the Fresnel approximation, the intensity distribution in the near field of observation is obtained. It is shown that the positions of intensity maxima in the near zone of observation are determined by a cubic equation. [ABSTRACT FROM AUTHOR]