摘要:

An analysis of photon correlation measurements for fluorescent light from a beam of two-level atoms is given where the number of pulse pairsn(τ) with time separation τ is recorded using a time-to-digital converter. These measurements are shown to correspond precisely to a subsequently normalized second-order correlation function (i.e. the normalization is performed after time averaging).

ISSN:0030-3909    

DOI:10.1080/713820289

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713820285

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

An arrangement is proposed in which the beam in a microscope traverses the object more than once. This results in the image of a single point for two passes through the object being 2·4 times as sharp as that in a conventional microscope, the side lobes also being extremely small. In the microscope in which the beam passes through the object twice the image amplitude behaves similarly to the image intensity in a conventional partially coherent microscope. Theoretical images of various objects are calculated, and the effects of using annular lenses discussed.

ISSN:0030-3909    

DOI:10.1080/713820284

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713820291

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

On calcule, en incidence axiale, les sections droites de rétrodiffusion et les sections droites bistatiques d'un ellipsoïde de révolution allongé et d'un demi-ellipsoïde posé sur un plan infini en utilisant, dans ce cas, la méthode des images optiques de Rayleigh. A cet effet, des programmes de calcul ont été réalisés.

ISSN:0030-3909    

DOI:10.1080/713820293

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713820290

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Light propagating through the atmosphere may have a phase-correlation scale different from the wave-correlation scale. These two scale lengths together with physically reasonable wave and phase autocovariance functions yield new predictions for atmospheric imaging characteristics such as image wander. These predictions are compatible with much of the limited experimental data available.

ISSN:0030-3909    

DOI:10.1080/713820287

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The luminance-brightness discrepancy is studied by comparing a white stimulus (A-illuminant) with a narrow-band one (red LED). The effect of test-field size is investigated in both simultaneous and successive brightness matches. The results are tentatively interpreted in terms of the ratio of chromatic to achromatic activity.

ISSN:0030-3909    

DOI:10.1080/713820292

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

It is shown that blazed computer generated holograms having a rotational symmetry (RSH) are especially suitable for interferometers working in reflected light which can be used in testing aspherics. The RSH acts either as a null lens of a very complex kind or it is used not only as beam splitter but also as beam combiner. From a more technical point of view, the latter version is especially interesting although in this case parasitic light caused by the double passage of all beams through the RSH may spoil the interference pattern. The two versions were tested experimentally. So, a Twyman-Green interferometer, on the basis of a blazed RSH, was built and tested. The interference pattern was free from severe disturbances because of the double passage through the RSH. Also a Fizeau interferometer was tested where the RSH acts as beam splitter and reunifer. Here the disturbances were more severe owing to the fact that the zero order as well as one first order of diffraction must be used. Possibilities for the suppression of stray light in this type of interferometer are discussed.

ISSN:0030-3909    

DOI:10.1080/713820286

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Dans certaines conditions, l'action d'un gradient élongationnel permet d'obtenir une déformation très importante des macromolécules souples se traduisant par l'apparition de biréfringence d'écoulement très localisée. On montre que des écoulements, à l'arrière d'obstacles, peuvent produire de tels effets. Dans le cas d'un dièdre à angle droit, on a tracé les courbes de biréfringence d'écoulement en fonction du débit en différents points du champ et pour différentes concentrations, mettant ainsi en évidence la nécessité d'un gradient élongationnel minimum pour obtenir le déploiement des macromolécules dissoutes. On note également la différence de comportement entre particules rigides et déformables.

ISSN:0030-3909    

DOI:10.1080/713820288

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor