摘要:

Surface plasmon-polaritons (SPP) have been excited on evaporated films of the transition metals nickel, palladium and platinum. Using the Otto geometry and a He/Ne laser operating at 3·391 μm we report the first characterisations of these metals using this technique. Adjusting the air-gap over the range 4 to 15 μm has allowed observation of > 95% coupling ofp-polarised (TM) radiation to the SPP and precise quantification of the optical dielectric constants of the metal films. The relatively large imaginary components so obtained mean that these materials may not readily be used in the Kretschmann geometry at this wavelength. By contrast the SPP resonances observed using the Otto geometry are sharp and open up potential for catalytic studies with SPP excitation on these metals.

ISSN:0950-0340    

DOI:10.1080/09500348914551481

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Extinction curves in the eikonal approximation and the anomalous diffraction approximation have been compared with exact extinction curves for homogeneous spheres of various refractive indices. Our results show the anomalous diffraction approximation to be more suitable for extinction calculations.

ISSN:0950-0340    

DOI:10.1080/09500348914551491

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In ‘Active Optics II’, the active correction of a 1 m test mirror was described in detail. A residual aberration term was found which still required correction in order to achieve the aim of the experiment: removal of all systematic defects leaving only statistical or high-frequency noise. The present paper describes the interferometric confirmation of the term and this final correction stage of the 1 m experiment.

ISSN:0950-0340    

DOI:10.1080/09500348914551501

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

We have analysed the behaviour of the atomic population inversion of the two-level atom interacting with a single-mode field initially prepared in the multiphoton Holstein-Primakoff SU(2) coherent state. It is shown that the behaviour of the atomic inversion depends on the parameters characterizing the initial state of the field. In particular, the atomic inversion can exhibit periodical oscillations as well as the collapse-revival phenomenon.

ISSN:0950-0340    

DOI:10.1080/09500348914551511

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A unified approach to the quantum statistics of single-mode linear processes described by the general Fokker-Planck equation and the generalized initial superposition of coherent and chaotic fields is developed to reveal the common traits in the mathematical models of several quantum optical systems. Processes such as the degenerate parametric amplification and the harmonic oscillator eventually coupled to the thermal or rigged reservoir are involved as special cases. A sufficient condition for the validity of the master equation is formulated as its being formally independent of possible reservoirs. The dependence of non-classical phenomena such as the sub-Poisson photon statistics and squeezing on the drift and diffusion coefficients is discussed.

ISSN:0950-0340    

DOI:10.1080/09500348914551521

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The unitary transformation induced by an optical element on polarisation vectors corresponds to a rotation of the associated vectors in polarisation space on the Poincaré sphere. The degree of violation of a Bell inequality, which is of central interest in discriminating between hidden variable and quantum theories, involves only scalar products in polarisation space, and so is invariant under joint transformation of the relevant polarisation vectors. Conventionally, the plane of polarisation of any analyser is switched by an angle ψ of, say, π/8. The same violation is predicted if, instead, the analyser switching is performed by adding a relative phase of 2ψ through field-dependent birefringence. As with recent optical demonstrations of the Berry phase, the doubling of the angle indicates the simplicity of a unified analysis of both types of switching in polarisation space.

ISSN:0950-0340    

DOI:10.1080/09500348914551531

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Geometric theory of the blazed aberration-corrected holographic grating is derived. This involves generalising the holographic component of the light-path function to permit aberration correction for recording geometries that arrange the two recording wavefronts to be incident from opposite sides of the grating substrate, thereby realising triangular or blazed groove profiles. The equation for the effective grating constant and an equation for the blaze angle are combined to yield a general expression for the recording angles in terms of the blaze angle, and the refractive indices of the grating substrate and the medium in front of the photoresist. This equation may then be solved simultaneously with the holographic aberration equations, to introduce the effective blaze angle and refractive indices as solution parameters. Also included are appendices that give essential equations for ray tracing, and for computing the blaze angle and blaze wavelength at any point on this type of grating.

ISSN:0950-0340    

DOI:10.1080/09500348914551541

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The theory of blazed holographic gratings given in a previous paper is applied to the design of a blazed holographic aberration-corrected spherical concave grating. Two solution types are found which cover different ranges of blaze wavelength and aberration. The use of the refractive indices of the substrate, and the medium in front of the photoresist, as optimising parameters is demonstrated. Four ray-traced solution examples are given which include the distributions of blaze angle and wavelength across the grating surface.

ISSN:0950-0340    

DOI:10.1080/09500348914551551

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The amplitude distribution at the aperture of an optical system for off-axis object points due to the introduction of a non-uniform transmission filter depends on the transmission function and on the longitudinal filter position. The effects of several filters on the axial and extra-axial point-spread function (PSF) and modulation-transfer function (MTF) of an optical system for different filter positions are studied. The filter transmission function and the filter position are obtained by the optimization of the axial and extra-axial Strehl ratios. The axial and extra-axial effects of the filters on the PSF and on the MTF are analogous. There are some positions of the filter for which the overall performance is significantly improved. The optimum longitudinal positioning of the apodizing filter is achieved in a process which is analogous to the stop shift effect in conventional optical design. The lack of radial symmetry in the off-axis wavefront aberration function at any particular field angle is convolved with the apodizing function and this leads to the anticipated improvement.

ISSN:0950-0340    

DOI:10.1080/09500348914551561

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The paper is concerned with the influence of the finite size of an incident beam upon both the anomalous-reflection spectrum and the shape of the energy distribution in a reflected beam. It is proved experimentally that the use of corrugated waveguides as a laser-resonator selective mirror improves the spatial coherence of radiation.

ISSN:0950-0340    

DOI:10.1080/09500348914551571

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor