Microscopy by Reconstructed Wavefronts in Proceedings of the Royal Society London A 197, 1949, pp. 454-487

Gabor, [D.] Dennis

Edité par Royal Society, London, 1949

A propos de cet article

BOUND FIRST EDITION OF GABOR'S FIRST EXTENSIVE PRESENTATION OF HIS 1971 NOBEL PRIZE WINNING "INVENTION & DEVELOPMENT OF THE HOLOGRAPHIC METHOD" (Nobel Prize). This work includes Gabor's first use of the word â??hologram' as well as three photographic plates. In 1948 Gabor sent a brief announcement of his new technology to Nature, then calling it an â??electron interference microscope' (Gabor, Nature, 161, 1948, p. 778). We offer that work separately. In 1947, the Hungarian physicist Dennis Gabor began his first steps toward improving the electron microscope; he wanted to produce "an instrument that could â??see' individual atoms" (Dictionary of Scientific Biography, Sup., 17, 325). Gabor understood that "despite gradual improvements in the resolving power of electron microscopes, a theoretical barrier set by a compromise between diffraction effects at the aperture edge and spherical aberration placed crucial practical limits short of the resolution needed to focus atomic lattices. Otto Scherzer first pointed out the limitation posed by spherical aberration in 1936 and attempted to calculate the limit to resolving power set by various imperfections. in 1943 the exact rule was elaborated by Walter Glaser. "For Gabor this provided just the kind of challenge his inventive mind needed. The barrier to progress was of a technical nature, yet formidable. Gabor had been searching for the â??trick' to get around the barrier of the theoretical limit to resolution. He was sitting on a bench at a local tennis club in 1947 when an idea suddenly came to him: Why not take an electron picture distorted by lens imperfections and correct it by optical means? A few calculations convinced him he was right. "Gabor [proposed] a two-stage process. In the first stage an interference pattern produced by the interaction of electrons diffracted by the object and a separate but coherent reference beam of electrons would be photographically recorded on transparent film. Gabor argued that this interference pattern, or "hologram" [as he would later call it in this paper] would carry the complete information needed to reconstruct an image of the object, using an optical system free from the limitations of electron optics. In the second stage, the hologram would be scaled up by a factor in the ratio of the wavelength of the light used in the reconstruction to the wavelength of the electron beam. The new hologram would then be illuminated with a light wave of the same aberration as the electron wave to, in theory, reveal an exact replica of the original object, magnified by the scaling factor" (ibid 326). "In 1947, Gabor began experiments "to establish the principle by using a purely optical model â?? that is, using visible light instead of electrons â?? with a mercury vapor lamp as a source of coherent light, to produce the interference photographs of simple two-dimensional images. Five months later he was able to show his close confidant Lawrence Bragg his first successful wavefront reconstructions: hazy images of simple printed words used as objects [three plates of these photographs accompany the paper]. Even when Bragg fully understood the theory, he still stated that it was a miracle it should work. "The first public indication of Gabor's success came with a preliminary note to Nature [in 1948]. The following year he wrote a more complete theoretical treatment [this paper] in which he introduced the word â??hologram' and indicated possible applications in light optics. Among these was the ability, using the same method, to record the data associated with 3-D objects in one interference object" (ibid). In the abstract this paper, Gabor very simply outlines what holography is and how it works: "The subject of this paper is a new two-step method of optical imagery. In a first step the object is illuminated with a coherent monochromatic wave, and the diffraction pattern resulting from the interference of the coherent secondary wave issuing from the object wit.

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Détails bibliographiques

• Titre: Microscopy by Reconstructed Wavefronts in Proceedings of the Royal Society London A 197, 1949, pp. 454-487
• Éditeur: Royal Society, London
• Date de parution: 1949
• Édition: 1st Edition.
• Catalogues du vendeur:
  • Classic Science, Microscopy, & Optics