Topic
Physical optics
About: Physical optics is a research topic. Over the lifetime, 5342 publications have been published within this topic receiving 101388 citations. The topic is also known as: wave optics.
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01 Jan 1991
TL;DR: In this paper, the authors describe the conversion of an object wave into amplitude and phase of the image wave by means of lenses; the aberrations of these lenses affect this process and holography allows us to correct these aberration during the reconstruction of the wave from the recorded hologram.
Abstract: Fundamentally, Transmission Electron Microscopy is wave optics, i.e. the object structure is encoded in the amplitude and phase of the emergent electron wave, which is then transferred into the image wave by the subsequent lenses. In conventional microscopy, only the intensity, i.e. amplitude squared, is recorded, whereas the phase is lost. This gives rise to severe loss of information about the object structure. Therefore, electron holography, which furnishes amplitude and phase separately, offers the only path to a complete understanding of the object structure including atomic positions and species, as well as intrinsic electric and magnetic fields. By means of an electron biprism the image wave is superimposed on a coherent plane reference wave giving rise to an interference pattern called a “hologram”. The position of the electron biprism in the optical path has to be optimized with respect to both intended lateral resolution and field of view. By means of light optical or numerical image processing, the amplitude and phase of the image wave are reconstructed from the hologram. For interpretation of the image wave in terms of the object, one has to understand in detail not only the interaction with the object but also the transfer of the object wave into the image wave. The conversion of amplitude and phase of the object wave into amplitude and phase of the image wave by means of lenses is described; the aberrations of these lenses affect this process and holography allows us to correct these aberrations during the reconstruction of the wave from the recorded hologram. Performance, as measured by achievable resolution and field of view, is finally limited by the degree of lateral coherence, i.e., by the brightness of the electron source.
120 citations
TL;DR: In this article, the concept of the frequency-domain physical-optics approximation to the time domain was extended to determine some significant properties of large reflector antennas, such as the effects of time-delayed mutual coupling between points on the surface.
Abstract: The authors extend the concept of the frequency-domain physical-optics approximation to the time domain, and use it to determine some significant properties of large reflector antennas. When this method is used to determine the equivalent surface-current density on the reflector, the effects of time-delayed mutual coupling between points on the surface are ignored. Consequently, many of the numerical limitations found in other conventional time-domain techniques are avoided, e.g. boundary-truncation error, interpolation error, numerical dispersion error, numerical instability, error accumulation with time marching, etc. More significantly, this method requires relatively small amounts of computer memory and CPU time. Several applications to the transient analysis of pulsed radar systems are given. >
120 citations
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TL;DR: An overview of the current state of the field and an outlook to future prospects is given in this paper, where the authors also present a survey of the state-of-the-art in the field of quantum optics with X-rays.
Abstract: Quantum optics with X-rays has long been a somewhat exotic activity, but it is now rapidly becoming relevant as precision x-ray optics and novel X-ray light sources, and high-intensity lasers are becoming available. This article gives an overview of the current state of the field and an outlook to future prospects.
120 citations
Posted Content•
TL;DR: In this paper, the authors derive the far-field pathloss using physical optics techniques and explain why the surface consists of many elements that individually act as diffuse scatterers but can jointly beamform the signal in a desired direction with a certain beamwidth.
Abstract: Intelligent reflecting surfaces can improve the communication between a source and a destination. The surface contains metamaterial that is configured to "reflect" the incident wave from the source towards the destination. Two incompatible pathloss models have been used in prior work. In this letter, we derive the far-field pathloss using physical optics techniques and explain why the surface consists of many elements that individually act as diffuse scatterers but can jointly beamform the signal in a desired direction with a certain beamwidth. We disprove one of the previously conjectured pathloss models.
119 citations
TL;DR: It is shown that the recently discovered phenomenon of so-called spectral switches has a natural interpretation in the framework of singular optics with polychromatic light and should be regarded as being primarily a manifestation of diffraction- induced spectral changes rather than correlation-induced spectral changes.
Abstract: It is shown that the recently discovered phenomenon of so-called spectral switches has a natural interpretation in the framework of singular optics with polychromatic light and that it should be regarded as being primarily a manifestation of diffraction-induced spectral changes rather than correlation-induced spectral changes as was suggested in the original papers [the first one appearing in Opt. Commun. 162, 57 (1999)] reporting this effect.
119 citations