Chapter 14 Dynamical diffraction of quantum beams: basic principles

A.B. Datsev, D.g. Rusev

Lee Yeong Kim, Ju Hyeon Lee, Yun-Tae Kim +4 more

We report on an experimental test of Babinet's principle in quantum reflection of an atom beam from diffraction gratings. The He beam is reflected and diffracted from a square-wave grating at near grazing-incidence conditions. According to Babinet's principle the diffraction peak intensities (except for the specular-reflected beam) are expected to be identical for any pair of gratings of complementary geometry. We observe conditions where Babinet's principle holds and also where it fails. Our data indicate breakdown conditions when either the incident or a diffracted beam propagates close to the grating surface. At these conditions, the incident or the diffracted He beam is strongly affected by the dispersive interaction between the atoms and the grating surface. Babinet's principle is also found to break down, when the complementary grating pair shows a large asymmetry in the strip widths. For very small strip widths, edge diffraction from half planes becomes dominant, whereas for the complementary wide strips the atom-surface interactions leads to a strong reduction of all non-specular diffraction peak intensities.

Mohammad Taghi Tavassoly

Using the Fresnel–Kirchhoff integral, we express the state of the light that diffracts from an aperture to a point, by superposition of two or more waves. The amplitudes of the waves are determined by the distances of the point from the ray optics borders of the emerging beams. The interference approach to the Fresnel diffraction leads to a universal formulation of the normalized intensity distribution on the diffraction pattern that determines the state of the incident light, the parameters of the aperture, and its distance from the observation plane, uniquely. In the photon approach, according to the uncertainty principle, confining the position of a photon to an aperture changes the probable propagation direction of the photon in an interval that leads to the diffraction of the photon or light. Thus, the normalized intensity distribution on the diffraction pattern is the probability distribution of a photon. To this probability distribution, a probability amplitude distribution is associated that diffracts similar to a wave in Fresnel diffraction. Applying the introduced approach to the study of the diffraction, from different simple apertures and phase steps, we deduce general behaviors of the Fresnel diffraction and show it is involved in all aspects of light phenomena.

Ehlotzky, Fritz

J. Trull

Photonics deals with the applications of light in science and technology including a vast number of different topics from engineering to telecommunications, to medicine, computing, metrology, and on and on. The book covers different topics related to the properties of the coherent interaction of light with matter in the frame of classical electrodynamics introducing the basic concepts in this field to undergraduate students and young researchers approaching this field. The contents include a revision of the fundamental properties of light and of the classical theory of light emission and intro-duces the basic equations describing the propagation of light beams and light pulses, including light propagation in uniaxial crystals and diffraction. A list of solved problems is included at the end of each chapter and the bibliography at the end covers both a basic and a more specialized literature for those students likely to go more deeply into the fascinating ideas of this field.

F. Ehlotzky