摘要:

A fast interference method for rough-surface diagnostics is presented based on the measurement of boundary-field phase dispersion, giving both high speed and accuracy.

ISSN:0950-0340    

DOI:10.1080/09500349114550011

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The effect of the intensity of the reference wave, a ‘zero’ component in the Fourier expansion of the object field, on the characteristics of a diffuse-object image reconstructed from a hologram without a reference beam is studied. The spatial-frequency spectrum of the reconstructed image is shown to be deformed when the coherent base intensity is lower than that of the object beam. It is shown that by taking the intensity of the reference wave higher than that of the object wave throughout the recording zone of a Gabor type hologram, it is possible to remove the nonlinear distortions of the reconstructed image, which cause deformations of the spatial-frequency spectrum.

ISSN:0950-0340    

DOI:10.1080/09500349114550021

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A basic nonlinear dynamical equation for pulse propagation in semiconductor-doped glass fibres is derived from the nonlinear wave equation using the slowly varying envelope approximation.

ISSN:0950-0340    

DOI:10.1080/09500349114550031

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A fast and accurate method to obtain dispersion-free propagation at different operating wavelengths in W-type optical fibre with a parabolic-index core is discussed. This is achieved by changing the thickness of the inner cladding and the refractive index of the outer cladding. The results are obtained using a constrained variational method.

ISSN:0950-0340    

DOI:10.1080/09500349114550041

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We examine the decay of two correlated atoms to a reservoir prepared in its ground state and in a squeezed multimode vacuum state. We calculate the entropies for the atoms and use the index of correlation to show the decay and regeneration of correlations between the atoms as they interact with the reservoir.

ISSN:0950-0340    

DOI:10.1080/09500349114550051

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Optical solitons in a medium with both resonant and non-resonant (Kerr-type) nonlinearities have earlier been shown to exist only under a definite relationship between the parameters of medium and radiation. In this paper, we study the influence of a small deviation from this relationship on the distortion of the soliton propagation. Our approach is realized via an algebraic version of the soliton perturbation theory formulated by means of the Riemann boundary problem. Corrections for the soliton parameters are calculated and an expression is obtained which describes the soliton shape deformation. Conditions of the soliton tail appearance are also analysed.

ISSN:0950-0340    

DOI:10.1080/09500349114550061

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The joint probabilityP12of detecting two photons at two different positions in the interference of a classical field with the resonance fluorescence field from a coherently driven two-level atom is investigated. We find thatP12shows a stronger modulation with detector separation than is predicted by a classical wave theory. Under stationary conditions and if the driving field is strong enough to saturate the atomic transition, the relative modulation amplitudeaof theP12pattern reaches its maximum possible valuea= 1 forE→ 0 (whereEis the classical field amplitude), but simultaneously the whole phenomena vanishes,P12→ 0. For equal intensities of the classical and the resonance fluorescent field we havea= ⅔. Compared with this, a classical wave theory predicts a possible maximum value ofa= ½.

ISSN:0950-0340    

DOI:10.1080/09500349114550071

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Starting from the inhomogeneous quantum-mechanical Maxwell equations we give a rigorous quantum-field theoretical derivation of the Langevin equations for a high-Qcavity field and specify the conditions of validity without borrowing from the standard relaxational treatment. In particular, we show that the use of Langevin equations means a loss of information about field changes during times of the order of the time of flight of a light signal through the cavity, which may be crucial in picosecond and femtosecond spectroscopy.

ISSN:0950-0340    

DOI:10.1080/09500349114550081

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The equations of motion of the simple quantum mechanical system are solved. The large-time limit of the solution gives the mutual wave function of two output photons. In the momentum presentation for the first photon and the coordinate presentation for the second, this function oscillates. Such oscillations may be observed using the simultaneous counting scheme.

ISSN:0950-0340    

DOI:10.1080/09500349114550091

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A quantitative measure of image enhancement is presented. It is based on the concept of ‘available information’ which is also defined here. We then apply these concepts to representative forms of image enhancement. The benefits derived from simple enlargement are put on a quantitative basis, as is the degradation due to excessive enlargement. It is shown that noise reducing techniques such as low-pass filtering do enhance an image, up to a point. Beyond this they degrade the image.

ISSN:0950-0340    

DOI:10.1080/09500349114550101

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor