摘要:

The effects of the coherence between the states of a two-level atom on the phenomenon of collapses and revivals in an undamped binomial state of the electromagnetic field are investigated. It is found that the Rabi oscillations exhibit qualitatively different behaviour for different phases of coherence between the levels. This behaviour in the binomial state of the field is in contrast with that in a coherent state field, in which case the Rabi oscillations are qualitatively the same for all values of the coherence between the two atomic levels.

ISSN:0950-0340    

DOI:10.1080/09500348914550671

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The statistical properties of two coupled nonlinear oscillators including losses are discussed using the statistics for the generalized superposition of coherent fields and quantum noise. Exact and approximate formulae for squeezing of vacuum fluctuations are derived. The photon statistics are shown to be Poissonian from the nonlinear dynamics of the lossless case. Non-classical behaviour is degraded by noise.

ISSN:0950-0340    

DOI:10.1080/09500348914550681

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The compression of high-energy femtosecond light pulses is investigated theoretically. The influence of an intensity variation across the beam cross-section and of changing the beam diameter along the path through a nonlinear medium are considered. The application of bulk media for the pulse shaping as well as the limits to this kind of compression are discussed.

ISSN:0950-0340    

DOI:10.1080/09500348914550691

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A new family of representations for one-dimensional functions or signals, obtained by performing a variable substitution cascaded with a Fourier transform mainly oriented to spectrum compression, is proposed. Some optical ways of performing such a transform are suggested. The case of the substitution x = cos u, connected with the Chebyshev transform (CT) is commented on in more detail. The minimax economization behaviour of such a transform is illustrated with some numerical examples for a certain class of input functions.

ISSN:0950-0340    

DOI:10.1080/09500348914550701

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The generation of squeezing of the square of the field amplitude (SSFA) in a system of coherent light interacting with thek-photon anharmonic oscillator is shown.

ISSN:0950-0340    

DOI:10.1080/09500348914550711

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Using a Gaussian function to approximate the modal field of a single-mode depressed cladding (or W-) fibre, we derive a simple expression for the modal spot-size, which depends only on the normalized frequency and two parameters that characterize the refractive-index profile. This spot-size can then be used to determine the expected splice and bend loss. The formalism for determining the spot-size can be generalized to approximate higher-order modes, which allows for a simple characterization of modal noise due to misaligned joints in single-mode fibres operating above cut-off.

ISSN:0950-0340    

DOI:10.1080/09500348914550721

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

When iteratively reconstructing a two-dimensional image (or, more precisely, its image-form) from appreciably contaminated samples of the magnitude of its Fourier transform, using Fienup's hybrid input-output algorithm, it is herein demonstrated by example that the image error, which expresses the violation of the image-space constraints, exhibits pronounced fluctuations. Significantly improved final image-forms are obtained by appropriately averaging the image-forms generated at those iterations for which the image error has local minima. Reconstructions for various specimen images are shown. A technique for accelerating the convergence of Fienup's algorithm, by initially estimating the phases of low spatial frequency components of the Fourier transform, is described and illustrated by example.

ISSN:0950-0340    

DOI:10.1080/09500348914550731

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The present work shows the behaviour of the phases in the determination of the surface electromagnetic waves in Kretschmann's configuration. The experimental arrangement employed is the same as the one used by Swalenet al., complemented with a polarization interferometer. We noticed that the phases provide a very precise account of the highest couplings.

ISSN:0950-0340    

DOI:10.1080/09500348914550741

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Partially coherent imaging occurs especially in microscopy and microlithography. The imaging properties of such systems are described by the ‘bilinear transfer function’ (BTF). This paper deals with an approximation of the BTF for conventional microscopy. The approximation allows the analytical calculation of image intensity distributions and the use of a combination of two transfer functions for the amplitude transmission spectrum. Examples of calculations of intensity distributions in the imaging of straight edges are given and compared with exact calculations.

ISSN:0950-0340    

DOI:10.1080/09500348914550751

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A numerical analysis of the total absorption of light (TAL) in shallow and deep metallic gratings with a sinusoidal profile is made for different wavelengths λ of incident light. For shallow groves, TAL is exhibited within a very narrow range of values of groove-depthhwhich is practically independent of λ. For deep grooves, TAL can be observed over a much broader range of values ofh, for example, at λ = 580 nm and groove separation d = 500 nm the reflectivity of the system could be less then 1% for 0·79 ⩽ h/d ⩽ 0·93, provided the angle of incidenceθis properly chosen.

ISSN:0950-0340    

DOI:10.1080/09500348914550761

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor