Symmetrical sampling of an interferogram with respect to zero path difference is usually difficult to achieve in Michelson interferometers while off-center sampled interferograms require double-sided exponential Fouri...
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Symmetrical sampling of an interferogram with respect to zero path difference is usually difficult to achieve in Michelson interferometers while off-center sampled interferograms require double-sided exponential Fourier transformation which is costly in computation time and degrades SNR. Several correction methods have been suggested by other authors that attempt to replace this transformation by an equivalent single-sided cosine transform. One such method utilizing a change of origin in the interferogram has been shown to lead to distorted spectra because of the effect of overlapping aliases. This distortion becomes particularly important for data involving smoothly varying spectra where over-all shape is important.
A light beam sufficiently intense to appreciably heat a gas it traverses will be deflected on account of the heat-induced gradients in the index of refraction. We compute these effects (bending into the wind, and self...
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A light beam sufficiently intense to appreciably heat a gas it traverses will be deflected on account of the heat-induced gradients in the index of refraction. We compute these effects (bending into the wind, and self-defocusing due to nonuniformities in the beam) for a nonzero wind velocity in the framework of geometrical optics. For each of the initial intensity distributions considered, a bending into the wind occurs, with accumulation of intensity in those regions in which the intensity gradient is negative. The beam becomes very sharp at a definite range, resulting in sharp bending and much detailed structure there; beyond, bending gives way to near-rectilinear propagation with uniform continuing beam spread.
In a paper probably to be published in Optika i Spektroskopiya the wave aberration for sagittal focus for the arbitrary surface of rotational symmetry has been carried out on the base of the astigmatic beam invariant ...
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In a paper probably to be published in Optika i Spektroskopiya the wave aberration for sagittal focus for the arbitrary surface of rotational symmetry has been carried out on the base of the astigmatic beam invariant Ds = nusds. The resulting expression for the wave aberration has been reformulated into three terms which, in the Seidel region, go over into astigmatism (the first) and into the Petzval curvature (the second) while the third disappears.
The method of partial distributions is used to calculate the population distribution of three level maser systems in which spontaneous emission and cross relaxation as well as thermal relaxation and induced absorption...
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The method of partial distributions is used to calculate the population distribution of three level maser systems in which spontaneous emission and cross relaxation as well as thermal relaxation and induced absorption processes are included. The results obtained are in agreement with the solution of the relevant rate equations. The method has the advantage of speed and suggestiveness. Two examples are presented: (1) A three level optical maser is analyzed in which one spontaneous emission transition probability is included. The solution in this example does not make the linear approximation to the Boltzmann factor. (2) A three level microwave maser is analyzed in which one cross relaxation mechanism is included. The solution to this problem by the method of partial distributions does require use of the linear approximation to the Boltzmann factor.
A method for automatic lens design is described, based upon the approximation of the curve describing the merit function plotted against a certain parameter, by a parabola. The minima of the parabolas of all design pa...
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A method for automatic lens design is described, based upon the approximation of the curve describing the merit function plotted against a certain parameter, by a parabola. The minima of the parabolas of all design parameters are then chosen as the new values of the corrected system. When the order of the parabola is either known or approached sufficiently close, this method results in a fast convergence and avoids oscillations around the minimum point of the merit function. It thus has definite advantages over the least squares or the steepest descent methods, although the time required for one iteration is doubled in comparison with the corresponding time in the other *** actual correction of a Cooke triplet both by the least squares and by the new method is outlined.
A practical solution to the least squares adjustment of an atomic energy-level array is described. This solution, in addition to the obvious advantages of satisfying the condition of least squares and providing a meas...
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A practical solution to the least squares adjustment of an atomic energy-level array is described. This solution, in addition to the obvious advantages of satisfying the condition of least squares and providing a measure of the standard error of the computed results, has the added advantage of being a solution readily adapted to computer use. As a computer program, the method uses a minimum of memory space and computer time.
A computational method of determining n and k for an evaporated film from the measured reflectance, transmittance, and film thickness has been programmed for an IBM 7094 computer. The method consists of modifications ...
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A computational method of determining n and k for an evaporated film from the measured reflectance, transmittance, and film thickness has been programmed for an IBM 7094 computer. The method consists of modifications to the NOTS multilayer film program. The basic program computes normal incidence reflectance, transmittance, phase change on reflection, and other parameters from the optical constants and thicknesses of all materials. In the modification, n and k for the film are varied in a prescribed manner, and the computer picks from among these values one n and one k which yield reflectance and transmittance values almost equalling the measured values. Results are given for films of silicon and aluminum.
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