摘要:

En faisant apparaître dans les relations de Fresnel la projection des vecteurs unité portant le champ électrique on établit des formules qui donnent une construction géométrique du vecteur de polarisation (et de l'amplitude du champ) après des réflexions ou des transmissions par des dioptres séparant des milieux homogènes et isotropes. On déduit de ces formules le rayonnement d'une répartition plane sinusoïdale de polarisation, ce qui permet de discuter brièvement du cas plus général où certains milieux sont magnétiques ou anisotropes. On a essayé de montrer toute la généralité de formules qui sont bien adaptées au calcul numérique.

ISSN:0950-0340    

DOI:10.1080/09500348914550521

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The already well known sensitivity of genuine quantum effects to loss processes is investigated for squeezing. Owing to the phase dependence of its quantum fluctuations, a squeezed state is extraordinarily fragile with respect to phase-destroying processes. This sensitivity increases with increasing degree of squeezing. A present coherent photon number enhances this disturbing effect.

ISSN:0950-0340    

DOI:10.1080/09500348914550531

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

External self-focusing and optical interference phenomena can appear in the transmitted field when a laser beam or pulse interacts with a thin nonlinear medium, and these effects have been investigated for different types of nonlinearity. Physical regimes have been considered where both nonlinear refraction and nonlinear absorption play important roles. Strong modulations in the transmitted irradiance can occur in principle when the incident-beam power is allowed to vary. This type of modulation does not generally die away as the power increases, moreover its amplitude and period will be markedly changed if the nonlinear absorption coefficient is allowed to increase. It is also shown that the shape of the incident transverse-beam profile strongly affects the nonlinear aberrations and interference effects, with implications for such applications as optical power limiting and transverse optical bistability.

ISSN:0950-0340    

DOI:10.1080/09500348914550541

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The reflectivities of plane Pt-Si multilayer mirrors of variousdspacings and layer thickness ratios have been measured as a function of angle, at wavelengths within the soft X-ray and EUV regions. The measured performance is compared with theory and the effect of heat treating the mirrors interpreted in terms of Pt film agglomeration. The imaging characteristics of a concave Pt-Si multilayer mirror are presented.

ISSN:0950-0340    

DOI:10.1080/09500348914550551

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Measurement of relaxation oscillation frequency can provide a convenient means for measurement of laser resonator losses. Expressions are derived which take account of the effect of non-uniform pump and laser beam profile on relaxation oscillation frequency and slope efficiency for a longitudinally-pumped four-level laser. Significant departures from plane-wave calculations are found. It is also shown that by combining a measurement of slope efficiency and relaxation oscillation frequency, the loss can be deduced without detailed knowledge of the pump beam profile. Experimental results supporting these calculations are described.

ISSN:0950-0340    

DOI:10.1080/09500348914550561

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The eigenfunctions and eigenenergies of the system composed of a cascade three-level atom and bichromatic or monochromatic field with arbitrary detunings are presented. The development of the state vector of the system with arbitrary initial conditions is obtained. The development of the quantum fluctuations and the second-order coherence degree for the field is calculated. The dependence of the squeezing and antibunching on the detunings, initial intensities and initial squeezing is studied. The contribution of single-photon and two-photon transitions to, and the influence of, the a.c. Stark effect on the squeezing are discussed.

ISSN:0950-0340    

DOI:10.1080/09500348914550571

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An asymptotic form of the density matrix for the field inside the cavity of a microscopic maser is derived. It is shown that it contains essentially the same information as that which has been inferred from numerical experiments in which the results of repeated measurements on the atoms as they leave the cavity have been taken into account. In particular, both approaches predict that the field, which is assumed to be initially of a thermal nature, evolves towards certain ‘trapping levels’. The analytic approach presented here is more general since it includes the evaluation of non-diagonal matrix elements.

ISSN:0950-0340    

DOI:10.1080/09500348914550581

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This work deals with the distributions of light-field energy density and energy flux density for the dielectric sphere characteristic of various, positive and negative, imaginary parts of the refractive index. Regular oscillations of the energy flux density on the particle's surface at resonance conditions are reported.

ISSN:0950-0340    

DOI:10.1080/09500348914550591

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A method is proposed to calculate the amplitude on the reference sphere due to a non-uniform transmission filter. The method may be divided into two stages: imaging of the filter plane, and projection of the filter image plane on the reference sphere. In this way we deduce some expressions which relate the coordinates on the filter plane to those on the reference sphere. Although the method is approximate, it has the advantage of saving computing time, since it is only necessary to trace two rays for each considered field. The accuracy of the method is studied by applying it to different real systems.

ISSN:0950-0340    

DOI:10.1080/09500348914550601

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This paper discusses the effect of an image's non-zero local mean value on the mean square estimation error (MSEE) and the steady-state weights of the two-dimensional least mean square (TDLMS) algorithm [1] when used in image processing. It shows that the local mean causes an increase in the MSEE which is proportional to the square of the image's local mean value. This causes the filter to converge to non-optimum weights and the shift from the optimum values is proportional to the square of the image's local mean value. It is shown that this effect can be reduced by normalizing the filter's weights to unity.

ISSN:0950-0340    

DOI:10.1080/09500348914550611

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor