ISSN:0030-3909    

DOI:10.1080/713820922

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713820916

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/716099596

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The familiar theory of information transfer in imaging using the prolate spheroidal functions and their eigenvalue spectrum is extended to allow the object and image domains to differ. The appropriate theory becomes one of singular functions and singular values, and in this paper we give a description of coherent imaging in these terms. Super-resolution in the sense of improving on previous criteria in the presence of noise can then be achieved, particularly at very low Shannon numbers, using the physical continued image, and we give quantitative estimates of such improvements for the linear, square and circular pupil cases. The theory is also shown to provide an efficient proof of the theorem that the number of degrees of freedom of a coherent isoplanatic imaging system is unaffected by phase aberrations in the pupil. Applications of these results in microscopy are outlined, and a practical method of implementation is proposed based on a generalization of numerical inversion techniques developed recently in the field of laser scattering.

ISSN:0030-3909    

DOI:10.1080/713820912

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Three- and four-dimensional signals can be replaced by two-dimensional sequences of sectional images if sampling in one or two dimensions is practicable. The convolution of such sequences yields, under certain conditions, the sequence representation of the three- or four-dimensional convolution result. Thus higher-dimensional filter operations can be performed by means of two-dimensional filter methods, e.g. coherent optics, whose parallel computing power matches the usually high space-bandwidth products (SBP) of such sequences. The possible throughput of coherent-optical setups is estimated. Experimental results for three-dimensional filter operations are shown.

ISSN:0030-3909    

DOI:10.1080/713820907

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Using the anomalous-diffraction (AD) light-scattering approximation, a relationship is derived between the scattering matrix of an object and its full Jones' matrix. This allows scattering to be calculated for dielectric objects having any kind of optical anisotropy, e.g. birefringent or optically active particles. The theory is used to calculate the small-angle light scattering (SALS) by a spherulite placed between two linear polarizers. Serious disagreements are found between the AD theory and the currently accepted theory of SALS based on the Rayleigh-Gans-Debye approximation.

ISSN:0030-3909    

DOI:10.1080/713820909

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Spatial coherence of laser light can be modified almost at will through the acousto-optic interaction. If a laser beam is phase-modulated in space and time by a progressive acoustic wave, its mutual intensity is made to vary with a period of one acoustic wavelength. When the double-slit separation is chosen to be half the acoustic wavelength, the double-slit image is more resolved with an increase in the acoustic power, and its resolution becomes better than it is for the incoherent limit if the acoustic power exceeds a critical level. These effects are explained by the spatial frequency analysis of the image spectrum.

ISSN:0030-3909    

DOI:10.1080/716099594

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Imaging characteristics of a cosinusoidal complex-amplitude object illuminated with acoustically phase-modulated laser light are investigated in association with periodicity, one of the most noticeable features of the acoustically modified mutual intensity of laser light. Because of this periodicity, the image contrast is much more enhanced with an increase in the acoustic power. This effect is explained by the fact that many higher-order components of the object spectrum are transmitted by a limiting pupil of the imaging system in the presence of the acoustic wave. Theoretical predictions are shown to be in good agreement with experimental results.

ISSN:0030-3909    

DOI:10.1080/716099594a

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A proposal is described for acoustic 2-D modification of optical mutual intensity. The use of two independent acoustic waves, progressing at right angles, produces the acoustically modified mutual intensity that varies in 2-D periodic manner. Since 2-D periodicity of the modified mutual intensity is recognized to be negligibly small within a circular object concerned, the computer-generated image pattern is almost uniform in the azimuthal direction of the image plane. The acoustically phase-modulated light illuminating the object forms an image whose ringing effect is appreciably suppressed. The rising of the image near its edge is superior to that for the incoherent limit.

ISSN:0030-3909    

DOI:10.1080/716099594b

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

We have derived the formulae for the radiation pressure exerted on a dielectric sphere in a gaussian laser beam from the scalar solution of the associated scattering problem. Following these formulae an optical potential well is formed by using two anti-parallel, collinear laser beams in which particles (polystyrene spheres, diameter 5·70 w m) suspended in water are trapped and held, in spite of substantial disturbance due to water convection.

ISSN:0030-3909    

DOI:10.1080/713820914

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor