BABINET, J. (JACQUES) - BABINET'S PRINCIPLE - EXTENDING THE FINDINGS OF FRAUNHOFER.

Sur les couleurs des réseaux,

(Paris, Crochard, 1829). 8vo. Without wrappers. In 'Annales de Chimie et de Physique', Series 2 , tome 40, Cahier 2. With halftitle to vol. 40. Pp. 113-224 a. 3 folded plates. (Entire issue offered). Babinet's paper: pp. 166-176 a. 1 plate.

First appearance of the paper in which Babinet expounds his importent law, stating the formula that holds between diffraction and diffraction pattern in optics. The principle plays an important role in antenna design and Babinet’s principle is particularly interesting to consider in this case where the metasurfaces and their complements can be regarded as variations on a folded dipole antenna array and patch antenna array, respectively. Babinet was together with Fresnel one of the pioneers in the development of the new optics, the wave-theory of light.

"An early proponent of the wave theory of light which had recently been perfected by Fresnel and Young, Babinet devoted much of his research to extending its applications. His first published paper on optics. "Sur les couleurs des réseaux," dealt with Fraunhofer’s discovery that white light viewed through a wire grating produces a series of continuous spectra. Babinet derived the formula that relates the deviation of rays of a given color to the ratio of their wavelength divided by the sum of the diameter of the wires plus the distance between any two wires. He also showed that diffraction experiments could yield an improved measure of wavelengths and presented a table of new values.

Babinet realized that the grating was only one of a number of means of producing diffraction effects, so he extended his theoretical work to include other systems. The result was a concept known today as Babinet’s principle: "If parallel rays fall normally on a diffraction system formed from a large number of openings... the diffraction phenomena will remain identically the same if the transparent parts become opaque, and reciprocally."(DSB).

Order-nr.: 45030