ISSN:0030-3909    

DOI:10.1080/713821057

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/716099605

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713821056

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Nous exposons un mode de traitement analytique et trois programmes de calcul numérique pour la détermination de l'intégrale BDW en vue de son application à une expérience de haute précision réalisée dans notre laboratoire. Dans cette expérience, un écran à bords rectilignes et parallèles diffracte la lumière cohérente d'un ensemble homocentrique d'ondes sphériques et produit, dans une région dite d'ombre géométrique, des franges d'interférences. La métrologie de la position de ces franges fournit des données de références auxquelles on compare les valeurs numériques calculées d'après la théorie de la BDW afin d'en évaluer la validité. Du point de vue théorique, nous tenons compte de l'hétérogénéité des ondes sphériques diffractées par l'écran, c'est-à-dire de la répartition non uniforme de l'amplitude sur les isophases. C'est, à notre connaissance, la première fois qu'on tient compte de ce facteur d'hétérogénéité dans l'application d'une théorie de la diffraction. Les trois programmes de calcul concordent à mieux de 10-6pour la position des franges, et 10-3pour leur structure en intensité. L'écart entre les positions des franges déterminées expérimentalement ou calculées est, en valeur relative, inférieur à 10-4. Dans une publication antérieure, il était de 4 × 10-4. Par comparaison avec tous les travaux publiés jusqu'ici, nous avons obtenu la meilleure concordance entre théorie de la diffraction et expérience.

ISSN:0030-3909    

DOI:10.1080/713821055

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The optical effects of gently deformed water surfaces are studied analytically for three examples: a straight floating edge, a small floating sphere and a dissipating free vortex. The surface deformation is obtained in the first two cases by solving Laplace's surface tension equation, and in the third case from the Bernoulli and Coriolis effects of a velocity field obtained from the Navier-Stokes equation. At small depths, a straight floating edge gives a normal shadow decorated by Fresnel fringes, but at greater depths the illuminated region is bounded by a caustic, giving a bright-edged shadow decorated with Airy-function fringes. A small floating sphere gives an approximately paraboloidal caustic decorated with bright Airy-function fringes (produced by the curved water surface), within which are faint Bessel-function fringes (produced by the ring of water bounding the sphere). A free vortex gives a caustic consisting of two roughly cylindrical sheets joined at a cusp-edged ring, whose section at a given depth consists of two concentric caustics bounding a bright annulus. The sphere and vortex theories are illustrated by experiments. All analytical results are expressed as universal functions whose dimensionless variables are related to the physical variables by scaling laws.

ISSN:0030-3909    

DOI:10.1080/713821046

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The effect of amplitude and phase fluctuations onN-photon excitation fromNindependent lasers is investigated. Each laser is assumed to have a multi-lorentzian line shape. The Fokker-Planck equation is solved to yield atomic density matrix equations which incorporate the fluctuations. Most of the results discussed are for the lowest-order approximation. No enhancement in the Rabi frequency or transition probability appears, but the Stark shift is found to be enhanced by a factor which is independent of the degree of non-linearity of the process. A general expression for the transition probability in the rate equation regime is presented and its characteristic features discussed. The difference betweenN-photon excitation fromNindependent lasers and from a single laser is examined.

ISSN:0030-3909    

DOI:10.1080/713821045

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The propagation effects of linearly polarized near-resonant laser radiation through a thermal ensemble of Doppler-broadened anharmonic oscillators are considered. The dynamical equations of motion are analytically solved by a perturbation approach to obtain the nonlinear polarization. Subsequent self-consistent analysis of the Maxwell wave equation then leads to a classical area theorem, which is in qualitative agreement up to third order with the corresponding quantum mechanical result. There is, however, a discrepancy between the respective coefficients of the third-order terms.

ISSN:0030-3909    

DOI:10.1080/713821050

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The extension of the plate diagram method to off-axis systems makes it possible to calculate the field curvature of the system under study only partially, since the system defined as the reference system contributes to that aberration. In this work the field curvature introduced by the reference system is calculated as a function of the variables which describe the diagram corresponding to the system being studied. Thus, the generalization of the method allows all the existing aberrations to be known.

ISSN:0030-3909    

DOI:10.1080/713821052

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A new interpretation of the self-imaging phenomenon using the Fourier plane of periodical objects is proposed. All properties of the self-images may be described, in the Fresnel approximation, by the quadratic phase corrections of the object Fourier transform. The angular dimensions of the self-images, as well as the notions of the constant of periodical field configuration and the self-image vergence, are introduced. They allow the characterization, in a uniform manner, of the field distribution in the whole space independently of the chosen self-image plane. The equivalency between the self-imaging phenomenon and the image defocusing by an optical system are considered. The general formulae for the harmonics analysis of the intensity distribution are derived.

ISSN:0030-3909    

DOI:10.1080/713821043

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The paper shows that, by suitably selecting the shape, dimensions and orientation of the diaphragm through which the moiré fringes formed by crossed gratings are viewed, the contrast of the fringe pattern of interest may be maximised with respect to accompanying noise. Computer simulation is used to give quantitative information regarding the improvement obtained. The results have potential application in the design of transducers for measuring displacement using moiré fringes.

ISSN:0030-3909    

DOI:10.1080/713821053

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor