摘要:

The hybrid acousto-optic spectrometer with semiconductor laser is investigated. The whole system is controlled by computer and it provides high signal-to-noise ratio and a large frequency band. The characteristics of a phased-array diode laser for the spectrometer are presented.

ISSN:0950-0340    

DOI:10.1080/09500348914551671

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An array generator is an optical system that splits an incoming beam of light into an array of many ‘beamlets’. Such a multiple beam-splitting system is necessary in optical data processing, where two-dimensional arrays of optical modulators, optical logic devices or optically bistable devices have to be read out optically or have to be provided with power-supply or bias beams. Other applications include multiple imaging and space-variant processing. The number of beams within an array has to be adapted to the size of the array of optical devices, also the modal shape of each single beam has to be adapted to the acceptable modes for the individual devices. Different systems for array generation are classified and compared with respect to their relevant parameters. Methods for modal adaptation are described. The influence of coherent noise and of chromatic errors is investigated. Non-Cartesian and irregular array generators are proposed.

ISSN:0950-0340    

DOI:10.1080/09500348914551681

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The problem of using evanescent fields in nonlinear optics is discussed by employing results on quantization of evanescent waves. It is shown that the peculiar properties of the momentum of evanescent modes can be used to realize non-critical optical frequency mixing. In the first illustration, the case of surface second-harmonic generation is discussed. It is then shown that, in the case of difference-frequency generation, it is possible to generate a ‘completely evanescent mode’ which is ‘trapped’ by the surface, which becomes a two-dimensional waveguide.

ISSN:0950-0340    

DOI:10.1080/09500348914551691

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

We show that near the resonant excitation of surface electromagnetic waves the amplitude of the reflected wave in a metallic film admits formally the same approximation as applies for gratings. Using this approximation it is easy to show that the phase exhibits different behaviour when the film thickness is above or below the critical value corresponding to the absorption of the reflected wave.

ISSN:0950-0340    

DOI:10.1080/09500348914551701

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0950-0340    

DOI:10.1080/09500348914551711

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The effect of dissipation on squeezed-state superposition states, generated in a nonlinear oscillator is investigated. Our results are presented in terms of theQ-function and the marginal distributions for a class of Hermitian operators.

ISSN:0950-0340    

DOI:10.1080/09500348914551721

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

We study the statistical properties of radiation in the single-mode phase states by evaluating the expression for the photon-counting distribution and its factorial moments. A detailed comparison has been made of the properties of phase states with those of coherent and chaotic states.

ISSN:0950-0340    

DOI:10.1080/09500348914551731

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A laser scanning microscope with different laser wavelengths is used to investigate internal binary states and diffusion parameters of integrated circuits. With blue laser radiation the internal logical levels in the integrated circuits could be detected. Red and i.r. radiation are used to investigate the depth and location of doped wells. Applying three wavelengths could distinguish between surface and bulk recombination.

ISSN:0950-0340    

DOI:10.1080/09500348914551741

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Numerical simulations of the field emitted by a point source in a medium with weak random variations of refractive index are often made using the paraxial form of the wave equation in Cartesian coordinates. In this case the representation of the point source can lead to problems. The present paper shows how these difficulties can be avoided by the appropriate use of circular coordinates. The form of the second and fourth moment equations in circular coordinates is also discussed.

ISSN:0950-0340    

DOI:10.1080/09500348914551751

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The random fluctuations of laser scintillation are described by the probability density function (PDF) of irradiance. Many models for a general PDF have been proposed, and a common method of analysis has been the comparison of the moments of the PDF with experimental data. The statistical behaviour of these estimates for the moments is determined by simulation of actual experimental procedures assuming various models for the true PDF. Realizations for histograms (estimates of the PDF) of digitized data are generated using binomial random deviates. Each realization for the histogram generates a realization for the moments. The PDF of these estimates for the moments is approximated by producing a histogram of a large number of such realizations. These results are compared with recent theoretical predictions. Higher moments are shown to be a poor description of the random process for typical experimental conditions. The effects of amplifier saturation are also investigated with the same simulations. Saturation becomes important when the median of the maximum irradiance becomes larger than the saturation level.

ISSN:0950-0340    

DOI:10.1080/09500348914551761

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor