摘要:

A novel method for the characterization of the processing of both absorption and phase holograms is proposed. Differently from the previous models, the square root of the diffraction efficiency of the processed hologram was directly related to the amplitude of the optical density modulation obtained at the developed step. This characteristic is a good indicator of the degree of nonlinearity of the hologram processing. While the Lin functions of phase holograms are similar to those of absorption holograms, the shape of the proposed function is completely different. The optical density and diffraction efficiency of holograms recorded using Agfa–Geveart 8E75HD plates and processed with AAC developer and a solvent bleach without a fixation step were measured and used to demonstrate the method.

ISSN:0950-0340    

DOI:10.1080/09500349808230885

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The depth profiling of a weakly absorbing sample using the crossed-beam photothermal deflection technique is theoretically described in terms of imaging resolution and contrast. The results show that, for the transverse deflection amplitude image of an optical or thermal defect in weakly absorbing material, the image contrast and depth-profiling ability increase markedly with increasing intersection angle of the two beams. Therefore an effective way to improve the resolution and contrast of the image is to increase the intersection angle, and the best image quality is obtained at normally crossed-beam case. The crossed-beam photothermal depth-profiling technique provides a quantitative microanalysis tool for the detection of optical or thermal defects located at any depth of weakly absorbing materials.

ISSN:0950-0340    

DOI:10.1080/09500349808230886

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this theoretical paper, formulae for important optical quantities of single layers with slightly randomly rough boundaries are derived by means of a generalized Rayleigh–Rice theory. Thus the formulae for the specular reflectances and ellipsometric parameters of the layers mentioned are presented. The theoretical results are illustrated by a numerical analysis. Practical features implied by this analysis to be relevant from the experimental point of view are introduced as well. Moreover, relations expressing the flux of scattered light are presented.

ISSN:0950-0340    

DOI:10.1080/09500349808230887

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new fabrication method of waveguide integrated elements immersed in shallow buried single-mode planar waveguides fabricated in glass substrates is proposed in order both to avoid scattering losses, by minimizing the interaction of the propagating field with surface irregularities, and to improve fibre–waveguide coupling performance. Likewise, by a proper choice of the waveguide characteristics, which are related to the fabrication parameters, both a high-single-mode-transmission regime and a high optical power in the waveguide element are obtained.

ISSN:0950-0340    

DOI:10.1080/09500349808230888

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In a micromaser, the evolution of cavity-field entropy and the Fano factor with the injected atomic number is investigated with and without the rotating-wave approximation. The micromaser may become a decreasing-entropy system under specific system parameters. Virtual-photon processes cause an additional quantum oscillation which relates to the atom–field coupling constant and the field frequency.

ISSN:0950-0340    

DOI:10.1080/09500349808230889

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We revisit the problem of identifying a Mueller matrixMthroughN=[Mtilde]GMwhereGis the familiar Minkowski matrix diag (1, −1, −1, −1) and the tilde denotes matrix transposition. Using the standard methods of reduction of symmetric matrices (tensors) to their canonical forms in Minkowski space, we then show that there exist only two algebraically distinct types of Mueller matrices, which we call types I and II, and obtain the necessary and sufficient conditions for a Mueller matrix in terms of the eigenproperties of the associatedNmatrix. These conditions identify a Mueller matrix precisely and completely unlike the conditions derived earlier by Givens and Kostinski or by van der Mee. Observing that every Mueller matrix discussed hitherto in the literature is of the type I only, we construct examples of type-II Mueller matrices using the more familiar type-I (in fact pure Mueller) Mueller matrices. Further, we show that everyGeigenvalue of anNmatrix (see section 2 for a definition) is necessarily non-negative. Using this result, in an accompanying paper, we derive a general three-term factorization of a Mueller matrix which yields the general forms of Mueller and Jones-derived Mueller matrices and completely solves the problem of their algebraic structure.

ISSN:0950-0340    

DOI:10.1080/09500349808230890

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We show that every Mueller matrix, that is a real 4 × 4 matrixMwhich transforms Stokes vectors into Stokes vectors, may be factored asM = L2KL1whereL1andL2are orthochronous proper Lorentz matrices andKis a canonical Mueller matrix having only two different forms, namely a diagonal form for type-I Mueller matrices and a non-diagonal form (with only one non-zero off-diagonal element) for type-II Mueller matrices. Using the general forms of Mueller matrices so derived, we then obtain the necessary and sufficient conditions for a Mueller matrixMto be Jones derived. These conditions for Jones derivability, unlike the Cloude conditions which are expressed in terms of the eigenvalues of the Hermitian coherency matrixTassociated withM, characterize a Jones-derived matrixMthrough theGeigenvalues andGeigenvectors of the real symmetricNmatrixN = [Mtilde]GMassociated withM. Appending the passivity conditions for a Mueller matrix onto these Jones-derivability conditions, we then arrive at an algebraic identification of the physically important class of passive Jones-derived Mueller matrices.

ISSN:0950-0340    

DOI:10.1080/09500349808230891

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A natural geometric representation of the polarization of light with fixed propagation direction is a dot on a sphere in an abstract space: the Poincaré sphere. If the direction of propagation is also included as a variable, a different description, given here, is natural. It is taken from quantum mechanics (from the Majorana picture of a spin system), spin one in the case of light. It characterizes polarized light bytwodots on a unit sphere in the real space of directions (i.e. by two unit vectors). The direction of propagation is their bisector (or its reverse). Projecting the two dots onto the plane perpendicular to this direction gives the two foci of the polarization ellipse (which lies in this plane and has a unit semimajor axis). As an application of this picture the geometric Berry phase for light is calculated. The result accords with the quantum spin-1 formula of Bouchiat and Gibbons, and with the prescription for finding the geometric phase for light given by Bhandari.

ISSN:0950-0340    

DOI:10.1080/09500349808230892

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We report the first study of frequency degenerate cubic optical nonlinearities in bulk metals across the melting point. Using pump–probe reflectivity and precise pump–probe polarimetry a strong femtosecond electronic nonlinearity (X(3)≈ 10−8esu) has been observed in indium. The effective nonlinearity sharply increases when the temperature approaches the melting point. We also report the results of a study on the nonlinearity of nickel films and discuss the effect of an interface with glass on the magnitude and sign of the nonlinearity.

ISSN:0950-0340    

DOI:10.1080/09500349808230893

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this work, we have used a new technique to characterize optically a periodically modulated metal–dielectric interface involving the measurement of the azimuthal-angle-dependent specular reflectivity. This method presents advantages over the conventional polar angle scan experiment since it requires no moving signal detector. The data recorded has been fitted to a conical version of Chandezon's differential formalism using a single set of parameters describing the grating profile and metal permittivity. The fitted grating profile is in good agreement with the form found by the use of an atomic force microscope. This work therefore provides a new procedure for characterizing gratings as well as a convincing test of conical diffraction theory.

ISSN:0950-0340    

DOI:10.1080/09500349808230894

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor