摘要:

Experimental data on silver ion-exchanged glass waveguides are presented. The waveguides are prepared by a three-step route consisting of two Ag+−Na+ion-exchanges alternated with a heat treatment, and exhibit peculiar refractive-index profiles. The reliability of two inverse Wentzel-Kramers-Brillouin reconstruction methods is also discussed for the systems at issue.

ISSN:0950-0340    

DOI:10.1080/09500349414550011

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A simultaneous modelling of surface and buried waveguides is presented. It is based on an approximate solution of the nonlinear diffusion equation solved under different boundary and initial conditions. Experimental results of buried waveguides produced by potassium-sodium exchange in soda-lime glass are presented.

ISSN:0950-0340    

DOI:10.1080/09500349414550021

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Using intensity-dependent polarization rotation as a passive mode-locking mechanism, pulses as short as 350 fs have been generated in an erbium fibre loop laser. Even in the cavities optimized for minimum-pulse-width generation, the response of the soliton structures to the periodic amplification gave rise to the now characteristic spectral side bands.

ISSN:0950-0340    

DOI:10.1080/09500349414550031

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We describe a simple combination of two quarter-wave plates and one half-wave plate of the same material, which can be used as an achromatic half-wave retarder.

ISSN:0950-0340    

DOI:10.1080/09500349414550041

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The application of dichromated gelatine transmission holograms as holographic optical elements for permutation components is demonstrated. These holographic deflection elements will be used as permutation components in a demonstrator for an optoelectronic switching network working with 1 GHz per channel. The use of a standard holographic material and recording process for faceted holograms for infrared light at 1·5 μm is investigated. The important parameters such as refractive index modulation of the gelatine, angular selectivity and scattering are investigated and compared with the corresponding results for visible light. It is shown that it is possible to produce holograms for infrared light with similar diffraction efficiencies to those for visible light.

ISSN:0950-0340    

DOI:10.1080/09500349414550051

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Diffraction effects may limit the spatial resolution and fidelity of soft X-ray lithography and contact microradiography, by scattering during transmission of X rays through a finite-thickness object, and in subsequent propagation to the image-recording plane. A numerical method is described to model such soft X-ray scattering effects, developed from the multislice method for electron diffraction calculations. Computer simulations are presented of scattering by sub-micron latex spheres used as test objects in contact microradiography, and carbon-like gratings used as lithographic masks. The calculated diffraction by spheres is shown to be consistent with experimental results and a rigorous Mie scattering calculation, and the calculations for gratings suggest the possibility of frequency-doubling lithography under carefully controlled conditions.

ISSN:0950-0340    

DOI:10.1080/09500349414550061

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Although usually discussed in the field of microscopy only, near field optics can have a number of other interesting applications in various fields of physics. Among these extensions we discuss here nonlinear near field optics. We show that when working inside the near field lying in the vicinity of a surface, the usual phase matching condition can be overpassed exactly as the Rayleigh criterion is overpassed in scanning near field optical microscopy. This can lead to applications both of technological and of fundamental interest. Principal properties of nonlinear near field optics are presented, and the nonlinear behaviour of a molecule trapped in a tip-sample junction is considered.

ISSN:0950-0340    

DOI:10.1080/09500349414550071

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We analyse the coupled modes propagation in a parallel-plate gyroelectromagnetic biaxial chirowaveguide. The transverse components of electric and magnetic fields in such bianisotropic waveguide are expressed in terms of the longitudinal components ofEandH, and the effects of different constitutive parameters on the dispersion characteristics as well as cut-off frequencies of propagating modes are demonstrated numerically. The results show that the processes of mode bifurcation and conversion also take place in the parallel-plate gyroelectromagnetic biaxial chirowaveguide.

ISSN:0950-0340    

DOI:10.1080/09500349414550081

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The squeezing properties of non-degenerate parametric amplification and oscillation with pump depletion and non-homogeneous absorption losses are studied. A method based in the Wigner representation is used which allows one, within a linearization scheme, to derive directly the Langevin equations for the involved optical fields from their quantum Heisenberg equations. Non-homogeneous absorption losses for the three beams are included in order to analyse the sensitivity of the squeezing spectra to the asymmetry of the losses. Intracavity squeezing spectra are calculated within this method both below- and above-threshold regimes. Special attention is given to the squeezing properties of the phase sum and amplitude difference of the correlated beams and amplitude of a single beam above threshold, where the role of loss asymmetry and pump losses is analysed in detail.

ISSN:0950-0340    

DOI:10.1080/09500349414550091

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A direct phase-to-height mapping algorithm for phase-measuring profilometry is presented and verified by experiments. The direct mapping formula can be generated by measuring the phases of several different parallel planes rather than geometric parameters of the optical system. Therefore, it can speed up the calculation and reduce systematic errors.

ISSN:0950-0340    

DOI:10.1080/09500349414550101

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor