As This Method of Imaging Becomes Better Understood, It Can Offer the Best Solution for Problems in Fields as Diverse as Architecture, Medicine and Mechanical Engineering

With the award of the 1971 Nobel prize in physics to Dennis Gabor, holography has reached a new pinnacle of prestige. Gabor won his prize for the invention of holography, a form of wavefront reconstruction in which a coherent reference wave appears to unlock a threedimensional replica of an object from a two-dimensional standing-wave pattern. The science of holography has taken some curious turns in its relatively short 25-year history. The time divides itself naturally into three periods: The first could be considered a precursor stage, when the aim was to record wavefronts diffracted from crystals that had been irradiated with x radiation or electron waves. If reconstruction with visible light were successful, a highly magnified image of the crystal lattice would result. Recording the phase of the radiation was, however, a difficult problem that was soluble only for rather special cases. (For a description of this early work, carried out principally by Sir Lawrence Bragg and Hans Boersch, see reference 1.) In 1948. Gabor developed a way to introduce a coherent background or reference wave, and the second period began.