Fourier Optics and the Synchrotron Light

Abstract

The nature of light, which has given rise to speculations since antiquity, proved to be a difficult subject. The first on record is the Greek philosopher, Sicilianborn,Empedocles (c. 490–c. 435B.C.)whose writingshavesurvived only in fragments so that his thinking is mainly known from reports in the work of Plato and Aristotle. Apparently the originator of the long-standing notion that all things are made of four elements — air, fire, water, and earth — Empedocles thought of light as a stream of small particles, emitted from a visible body, that were to enter the eyes and return to the originating body, traveling with finite speed. At other times he thought of light as originating in the eyes and returning to the eyes after reaching the object.