1,721,014 research outputs found
Coherence and the spatial distribution of intensity
No full textThe Gupta method leads to the determination of the optical constants of an absorbing material through Iwo measurements of reflecljvity. In this paper, the effect of experimental errors on both the accuracy of the determination and the conditions for the achievement of unambiguous results is studied
Accuracy in the Gupta method of optical constant determination
No full textThe Gupta method leads to the determination of the optical constants of an absorbing material through Iwo measurements of reflecljvity. In this paper, the effect of experimental errors on both the accuracy of the determination and the conditions for the achievement of unambiguous results is studied
Orbital angular momentum of light: a simple view
No full textWe present a simple model for the orbital angular momentum of a light beam. Using heuristic arguments, we evaluate the expectation value of such a quantity for a photon. The resulting expression coincides with that derived from Maxwell’s equations. Examples are given to illustrate the main points
Evaluation of the modal structure of light beams composed of incoherent mixtures of Hermite-Gaussian modes
No full textA new, to our knowledge, technique for determining the modal content of partially coherent beams that are made up of an incoherent superposition of Hermite-Gaussian modes is studied. The algorithm makes use of the intensity profile of the beam at an arbitrarily chosen transverse plane. Analytical derivations are presented for a Gaussian Schell-model source and flat-topped beams, as well as an analysis of their performances in the presence of experimental errors and noise. Numerical simulations are performed to test the accuracy and the stability of the recovery algorithm
Intensity-based modal analysis of partially coherent beams with Hermite-Gaussian modes
No full textMany partially coherent beams are made up of a superposition of mutually uncorrelated Hermite-Gaussian modes. We prove that knowledge of the transverse intensity profile of such a beam is sufficient for evaluating the weights of the modes in an exact way. Simulations indicate that the proposed method resists noise well
Buoyancy-induced flows monitoring by digital speckle photography and Fourier transform analysis
No full textBeam coherence-polarization matrix
No full textWe present an approach for describing the properties of a quasi-monochromatic, beam-like field that is both partially polarized and partially coherent from the spatial standpoint. It is based on the use of a single 2 x 2 matrix, called the beam coherence-polarization matrix, whose elements have the form of mutual intensities. This approach, which can be viewed as an approximate form of Wolf's general tensorial theory of coherence, appears to be very simple, yet it is able to cover significant aspects of the beam behaviour that would not be accounted for by a scalar theory or by a local polarization matrix approach. A peculiar interference law applying to mutual intensities is derived. We show through simple examples how this approach leads to distinguish fields that would appear identical in a scalar treatment or in a local polarization matrix description. Hints for extensions are given
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