ISSN:0950-0340    

DOI:10.1080/09500349114550251

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In the present paper we show that there is a whole family of equations describing semiclassically the coherent dynamics of a system consisting ofNtwo-level atoms (N≫ 1) under different physical situations, that may be analysed using an analogy with the one-dimensional classical motion.

ISSN:0950-0340    

DOI:10.1080/09500349114550261

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper is the fourth, and last, in the series on active optics as realized in the ESO New Technology Telescope (NTT). It gives a detailed description of the set-up and optimization of the optical system, based on the three levels (i.e. time frequencies) of active correction. The first results in direct imagery with the telescope optimized only near zenith (‘Astronomical First Light’) yielded immediately the best star images ever recorded in ground-based astronomy with a full-width-half-maximum of 0·33 arcsec on a CCD detector with pixels of 0·123 arcsec diameter.

ISSN:0950-0340    

DOI:10.1080/09500349114550271

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A tensor operator formalism is proposed for the complete description and computation of the local state of polarization of a monochromatic arbitrary vector field. The formalism is invariant under the three-dimensional orthogonal group. Starting from the unit norm polarization vectore, a Hermitian polarization dyadic is defined by[Pcirc] = ee* = Ŝ + Â, ŜandÂbeing the symmetric and the antisymmetric parts of[Pcirc]. The 3 × 3 matrices of[Pcirc]> ŜandÂare singular, this providing a general definition of field transversality. The field's vibrations are transverse to the common eigenvector belonging to the zero eigenvalue. The transverse eigenequations forŜ Âand[Pcirc]are solved and three pairs of linear, circular and elliptic polarization eigenstates are obtained. The three pairs of transverse eigenvectors are related by unitary transformations and are used as orthonormal bases for the expansion of the statee. It is shown that[Pcirc] ŜandÂare field observables. The Poincaré sphere representation is derived from the polarization dyadic formalism.

ISSN:0950-0340    

DOI:10.1080/09500349114550281

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We introduce quasi-photon phase states of radiation in the single mode, and study the fluctuations in the measured phase operators. We also show that these states exhibit bunching, unlike coherent states which show no bunching.

ISSN:0950-0340    

DOI:10.1080/09500349114550291

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The squeezing properties of the multiphoton Hamiltonian with intensity-dependent coupling are evaluated for the◯and[pcirc]xquadratures, for the initial state of a coherent electromagnetic field and an atom in the ground state. Two measures of squeezing: the percentage of total squeezing and the squeezing time-period percentage, are introduced. Interesting squeezing properties with respect to◯are observed for real coherent states when the time evolution of the above measures and of the time-averaged squeezing are analysed. The multiphoton intensity-dependent coupling Hamiltonian is found to be almost independent of the specific powers of the annihilation and creation operators, as long as the sum of the powers is kept constant.

ISSN:0950-0340    

DOI:10.1080/09500349114550301

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A theoretical analysis of mode conversion induced by photorefractive damage in optical waveguides is presented. The model applies to any geometry and uses the well known coupled-wave approach which has been extended to anisotropic media. The light-induced coupling coefficients have been expressed in terms of the photorefractive space charge field. The formulae have been, then, applied to calculate the initial conversion rate of a fully confined mode in a planar LiNbO3waveguide perpendicular to thecaxis. The photorefractive field developed by illumination has been obtained under a short-time (initial) approximation, taking into account all transport processes. Some numerical estimates on mode conversion rates are also given and compared to available experimental data.

ISSN:0950-0340    

DOI:10.1080/09500349114550311

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A relativistic theory of polarization and magnetization due to an electromagnetic field is developed in powers of the electric and magnetic components,EandB. For an observer in the rest frame of an earthbound laboratory the observable birefringence using the light from a distant galaxy as a source of radiation becomes dependent on the velocity of that source through the Lorentz transformations. Circular birefringence and dichroism, angle of rotation, and related effects for the same optically active material using earthbound and galactic sources would provide data dependent on the velocity of the source frame with respect to the rest frame. This amplifies the birefringence to the point where tiny parity-violating effects may become observable in the rest frame of the earthbound observer.

ISSN:0950-0340    

DOI:10.1080/09500349114550321

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We present a new method to obtain a vectorial solution of the Helmholtz equation for large homogeneous scatterers having a cylindrical symmetry and an approximately spherical shape. Limitations of the method for arbitrarily shaped particles are discussed.

ISSN:0950-0340    

DOI:10.1080/09500349114550331

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The propagation of Gaussian beams through lenslike media with gain or loss is analysed in order to discuss the transformation of these beams into uniform beams. The results obtained are applied to a lenslike medium with gain increasing along the radial direction.

ISSN:0950-0340    

DOI:10.1080/09500349114550341

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor