摘要:

The Sénarmont compensator has been used for many years to measure the phase retardation between the two components of an elliptically polarized beam of light. This letter shows how the operation of this device actually makes use of the geometric phase.

ISSN:0950-0340    

DOI:10.1080/09500349314552081

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The transmission and cross-coupling characteristics of a surface-plasmon-based polarization beam splitter with multimode interlay between two polished optical fibre blocks are presented. Through the continuous monitoring of the characteristics as a function of interlay refractive index and wavelength it was found that the device is symmetrical in terms of optical power coupling in the cross direction and asymmetrical in terms of transmission, with respect to input launch direction. The fibre fixed in the metal-coated block has a transverse electric (TE) mode transmission which is independent of the refractive index of interlay. The transmission of the other (uncovered) block shows resonance-type interaction for both TE and transverse magnetic modes owing to evanescent field coupling to the multimode interlay.

ISSN:0950-0340    

DOI:10.1080/09500349314552091

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We consider the resonant interaction of a two-level atom with a thermal state of the quantized field in a lossless cavity. Non-trivial dynamics of the atomic dipole moment and the field quadrature components arise if the atom is initially prepared in a coherent superposition of its upper and lower states. In particular, the initial thermal field state acquires a well defined phase that corresponds to the initial phase of the superposition atomic state. Population trapping occurs when the intensity grows.

ISSN:0950-0340    

DOI:10.1080/09500349314552101

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The van Cittert-Zernike theorem is used to obtain in a rigorous way the bidimensional glitter function used in the problem of retrieving spatial information of surface heights from aerial images. The results show that the glitter function can be described by a circular function where the radius is a function of the angular extent and the position of the source and the viewing direction. This result comes from considering the source as a circular one that is projected on the detector or camera after reflection, taken into consideration the slopes of the surface and the geometrical optics.

ISSN:0950-0340    

DOI:10.1080/09500349314552111

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A new technique for continuous phase determination of an interferogram based on a digital phase locked loop is presented. The main advantage of this method, with respect to well established techniques such as Fourier or phase stepping demodulation, is that the traditional approach to phase unwrapping processes by removal of discontinuities is not required. The phase is determined continuously as the phase locked loop scans the two-dimensional interferogram. Because of the sequential nature of the algorithm proposed, this can be implemented using a special purpose video processor for phase determination at video rates. The above mentioned properties makes the presented technique a fast algorithm for phase determination of carrier frequency interferograms modulated by a two-dimensional smooth phase function.

ISSN:0950-0340    

DOI:10.1080/09500349314552121

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An inverted surface plasmon resonance is observed by measuring the internal reflectivity of a bilayer chromium-gold thin film deposited on a high index glass prism. With incident transverse magnetic radiation and suitable choice of chromium and gold thicknesses a strong resonance maximum is recorded which is nearly as narrow as the more commonly observed surface plasmon resonance minimum for gold. A peak reflectivity of order 40% has been recorded which with fine adjustment of the film thickness may be increased to perhaps 80% although it never approaches 100% because of the intrinsic absorption by the chromium. The angle dependent reflectivity data obtained are analysed using a multilayer Fresnel equation model and optical field and power loss profiles through the resonance are presented to illustrate its nature.

ISSN:0950-0340    

DOI:10.1080/09500349314552131

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Photon statistics and non-classical behaviour of light produced in the optical parametric process are studied in the approximation of small fluctuations around a stationary point. The depletion of the pump mode is included. An initial generalized superposition of a coherent state and noise as well as the influence of reservoir noise and internal losses are considered.

ISSN:0950-0340    

DOI:10.1080/09500349314552141

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The reprocessibility of dichromated gelatin reflection gratings is studied. Reflection gratings developed in six slightly different ways are reprocessed after three years storage. Reflection (diffraction) efficiencies are strongly decreased during storage. After reprocessing reflection efficiencies are close to the original reflection efficiencies. Restoration is better when the original reflection efficiency (RE) is not very high (RE <90%). When, the plates, which are rapidly dehydrated during development procedure, are reprocessed using slow dehydration, reflection efficiencies have often been even better after reprocessing than one day after exposure and the original development procedure.

ISSN:0950-0340    

DOI:10.1080/09500349314552151

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A Young's interferometer has been used for spatial coherence measurements of the 23 mm diameter laser beam provided by a XeCl laser fitted with a super-Gaussian resonator of magnification factor M = 7. It has been found that the fringe visibility reduces from 0·8 to 0·1 by increasing the slit distance from 4 mm to 15 mm, the transverse coherence degree of the laser beam being determined by the geometric constraints imposed by the unstable resonator.

ISSN:0950-0340    

DOI:10.1080/09500349314552161

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We describe our study of the spatial resolution of a phase-conjugating ring-resonator (PCR) consisting of a Sagnac interferometer and a phase-conjugating mirror based on four-wave mixing in photorefractive BaTiO3. The use of optical image processing systems depends on the amount of information channels and the nonlinear coupling between the channels. The spatial resolution or the number of independent pixels is important to describe any image processing system. If the gain of the phase-conjugating mirror is higher than the losses in the passive part of the system, then the system exceeds the threshold, and without any externally incident signal the resonator shows the effect of self-oscillation. From the analysis of this self-oscillation pattern we have calculated the spatial resolution of the PCR. Additionally, we try to investigate the pixel coupling of the system by defining channels in the resonator. By changing the geometrical set-up of the system it is possible to observe a controlled coupling between neighbouring channels.

ISSN:0950-0340    

DOI:10.1080/09500349314552171

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor