The dependence of the refractive index of Bi 12 GeO 20 on pressure (0.001 to 14 kbar) and temperature (20 to 330°C) is reported at different wavelengths between 0.5 and 0.7 μ m. We have analyzed our data in term...
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The dependence of the refractive index of Bi 12 GeO 20 on pressure (0.001 to 14 kbar) and temperature (20 to 330°C) is reported at different wavelengths between 0.5 and 0.7 μ m. We have analyzed our data in terms of Kettler, Sellmeier–Drude, and Lorentz–Lorenz dispersion formulas; however, in close parallel with the results of our study of the ORD, it is found that even with these data no unique choice can be made among the various models such that all the data would be described by it. In order to make this choice, all of the data obtained from both the refractive and ORD studies were then considered. It is then found that a Sellmeier–Drude formula describes our data on n (λ) and the Agranovich-type formula is favored, though not overwhelmingly, for the ORD data of Bi 12 GeO 20 .
White and Straley have reported room-temperature optical constants, α , κ , and ∊ 2 for AgCl that exhibit negative, unphysical dips at the band edge. Because Morrison also obtained such behavior for InAs, InSb, and ...
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White and Straley have reported room-temperature optical constants, α , κ , and ∊ 2 for AgCl that exhibit negative, unphysical dips at the band edge. Because Morrison also obtained such behavior for InAs, InSb, and GaAs, we have studied possible sources of this anomaly. An artifact of the experimental reflectance data near this energy is found to be responsible. No defect in the Kramers–Kronig transform or its use is implied, contrary to some suggestions. The corrected optical constants of AgCl were modified by ~10% up to 5 eV, whereas at higher energies they were barely affected. Thus Kramers-Kronig-deduced optical constants that exhibit unusual structure are not affected by this structure at other energies. The new AgCl results are presented, and assignments are briefly discussed.
A method based upon the Laguerre–Gauss quadrature for the integration of Planck’s equation over any specified spectral band is presented. The accuracy of the quadrature, binomial-expansion, and Chebyshev-polynomial ...
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A method based upon the Laguerre–Gauss quadrature for the integration of Planck’s equation over any specified spectral band is presented. The accuracy of the quadrature, binomial-expansion, and Chebyshev-polynomial methods are determined and compared.
Wavefront shearing interferometers have inherent advantages over more conventional interferometers because they do not need a separate reference wavefront. However, the fringe patterns are less directly related to the...
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Wavefront shearing interferometers have inherent advantages over more conventional interferometers because they do not need a separate reference wavefront. However, the fringe patterns are less directly related to the wavefront shape. In this paper, a method is described that uses data obtained from two lateral shear interferograms sheared in orthogonal directions to describe a wavefront of any arbitrary shape. Analysis of the data defines the wavefront on a regular grid, using a least squares criterion to match the measured data to the reconstructed shear data. Because each point on the final wavefront is involved in at most four measurements, the matrices tend to have many zero elements, making them easily solvable by simple numerical techniques, even for several hundred points. An error analysis indicates that the accuracy of the final results can be as good as the accuracy of the measured data. The procedure is described, and results of a typical analysis are shown.
The consequences of causality and analyticity are commonly invoked in procedures for determining optical constants from reflectance data using the Kramers–Kronig relation. Here an entirely elementary argument is adva...
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The consequences of causality and analyticity are commonly invoked in procedures for determining optical constants from reflectance data using the Kramers–Kronig relation. Here an entirely elementary argument is advanced, which exploits only the parity of Fourier transforms and the vanishing of the impulse response for negative times, and which avoids the concept of analyticity. This leads to a simply understood algorithm for such computations. The new procedure shows large gains of computational efficiency over the classical Kramers–Kronig approach. The method is applied first to model data and compared with exact results; it is then applied to real data and compared with the result obtained by the standard method. Excellent agreement is obtained in all cases.
The problem of determining color distance between two arbitrary colors is considered. The color solid is assumed to be a riemannian space so that small color differences can be described by a quadratic form in the thr...
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The problem of determining color distance between two arbitrary colors is considered. The color solid is assumed to be a riemannian space so that small color differences can be described by a quadratic form in the three-dimensional color space. The geodesics and the corresponding distances are generated by a steepest-descent method with fast convergence and small storage requirements on the digital computer. The results are illustrated by means of tables and graphs.
With the goal of producing larger working regions of uniform irradiance and phase in microwave anechoic chambers, we have built a disassemblable, tapered chamber in which to study the effects of (a) source size and (b...
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With the goal of producing larger working regions of uniform irradiance and phase in microwave anechoic chambers, we have built a disassemblable, tapered chamber in which to study the effects of (a) source size and (b) source position. Recognizing that the long walls of tapered anechoic chambers are partially reflecting mirrors, we have developed an elementary theory for optical design of chambers, and made computations that agree with microwave experiments. To design wider plateaus of irradiance in the working region, we have used computer programs for the interference patterns produced by the primary source and the multiple-image virtual sources.
Optical properties of vacuum-deposited silver films have been investigated by ellipsometry. A method of calculating optical parameters has been developed and applied to this investigation. On the assumption that the f...
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Optical properties of vacuum-deposited silver films have been investigated by ellipsometry. A method of calculating optical parameters has been developed and applied to this investigation. On the assumption that the film is optically isotropic, n , k , and d are simultaneously determined by the measured values of ψ , Δ, and the transmittance of p -polarized light. For very thin films, those isotropic parameters show an anomalous behavior, and for thinner films, the computation for determining them does not converge. The computation converges only when the optical anisotropy of the film is taken into account, and the convergent range of the anisotropic parameters is determined. The convergence range includes the anisotropic parameters predicted by the theory for the optical properties of an aggregated silver film. An anomalous increase of the isotropic parameters with decrease of thickness, for thinner films, arises from regarding the anisotropic film as isotropic.
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