About: Collimated light is a(n) research topic. Over the lifetime, 17272 publication(s) have been published within this topic receiving 180982 citation(s).
Papers published on a yearly basis
Abstract: The effect of a plate of anisotropic material, such as a crystal, on a collimated beam of polarized light may always be represented mathematically as a linear transformation of the components of the electric vector of the light. The effect of a retardation plate, of an anisotropic absorber (plate of tourmaline; Polaroid sheeting), or of a crystal or solution possessing optical activity, may therefore be represented as a matrix which operates on the electric vector of the incident light. Since a plane wave of light is characterized by the phases and amplitudes of the two transverse components of the electric vector, the matrices involved are two-by-two matrices, with matrix elements which are in general complex. A general theory of optical systems containing plates of the type mentioned is developed from this point of view.
TL;DR: An intense collimated beam of high-energy protons is emitted normal to the rear surface of thin solid targets irradiated at 1 PW power and peak intensity 3x10(20) W cm(-2).
Abstract: An intense collimated beam of high-energy protons is emitted normal to the rear surface of thin solid targets irradiated at 1 PW power and peak intensity 3x10(20) W cm(-2). Up to 48 J ( 12%) of the laser energy is transferred to 2x10(13) protons of energy >10 MeV. The energy spectrum exhibits a sharp high-energy cutoff as high as 58 MeV on the axis of the beam which decreases in energy with increasing off axis angle. Proton induced nuclear processes have been observed and used to characterize the beam.
TL;DR: The mineral content of bone can be determined by measuring the absorption by bone of a monochromatic, low-energy photon beam which originates in a radioactive source and is measured by counting with a scintillation detector.
Abstract: The mineral content of bone can be determined by measuring the absorption by bone of a monochromatic, low-energy photon beam which originates in a radioactive source (iodine-125 at 27.3 kev or americium 241 at 59.6 kev). The intensity of the beam transmitted by the bone is measured by counting with a scintillation detector. Since the photon source and detector are well collimated, errors resulting from scattered radiation are reduced. From measurements of the intensity of the transmitted beam, made at intervals across the bone, the total mineral content of the bone can be determined. The results are accurate and reproducible to within about 3 percent.
TL;DR: A new and fundamentally different X-ray method is described, in which the cranium is scanned in successive layers by a narrow beam of X rays, in such a way that the transmission of the X-rays across a particular layer can be measured, and by means of a computer, used to construct a picture of the internal structure.
Abstract: A new and fundamentally different X-ray method is described. The cranium is scanned in successive layers by a narrow beam of X rays, in such a way that the transmission of the X-ray photons across a particular layer can be measured, and by means of a computer, used to construct a picture of the internal structure. Employing a suitably designed scanning gantry, a continuously operating X-ray tube, and a narrow collimated X-ray beam, the transmissions of X-ray photons across a slice of tissue may be measured by a system of crystal detectors in such a way that 28,800 readings are obtained. These form the basis of 28,000 simultaneous equations which are solved by a computer. The solutions are transformed into absorption coefficients and by means of a suitable algorithm related to their correct cells in a matrix of chosen size. The results are stored, computed, and then made available from a magnetic disc to construct a picture on a CRT. The numerical results are available from a print-out. The examin...
Abstract: We found that self-determining collimated light is generated in a photonic crystal fabricated on silicon. The divergence of the collimated beam is insensitive to that of the incident beam and much smaller than the divergence that would be generated in conventional Gaussian optics. The incident-angle dependence of the self-collimated light propagation including lens-like divergent propagation was interpreted in terms of the highly modulated dispersion surfaces with inflection points, where the curvature changes from downward to upward corresponding to respectively a concave/convex-lens case. This demonstration is an important step towards controlling beam profile in photonic crystal integrated light circuits and towards developing “photonic crystalline optics.”