ISSN:0950-0340    

DOI:10.1080/09500349114550621

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The effect of optical amplification on the signal-to-noise ratio of autocorrelation measurements has been investigated experimentally. A light signal containing correlation information was amplified by an inverted population (phase-insensitive) optical amplifier. The data clearly show that the amplification may either degrade or enhance a subsequent autocorrelation measurement, depending on the experimental conditions. In particular, enhancement is possible when the detector quantum efficiency is low, or its noise is high. However, when all the signal photons are already being detected with no extra noise, then any optical amplification will inevitably lead to degradation of the data quality, due to addition of amplified spontaneous emission noise (ASE) from the amplifier itself.

ISSN:0950-0340    

DOI:10.1080/09500349114550631

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Signal fluctuations in a coherent, continuous-wave, lidar operating at 10·6 μm were investigated by forming temporal autocorrelation functions of intensity. The scattered radiation was taken from a model target consisting of a moving belt, and was studied under a wide variety of illumination conditions. Certain of the results confirmed simple, physical, semi-intuitive expectations of the speckle fluctuations due to object translation. Other measurements showed considerable complexity with large changes of not only characteristic coherence time but also shape of the autocorrelation functions. These findings are analysed in detail, are related to theoretical discussion, and are satisfactorily explained in terms of the relative balance of mechanisms involving target translation, tilt and ripple.

ISSN:0950-0340    

DOI:10.1080/09500349114550641

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A general uniaxial medium is characterized by its permittivity and permeability tensors having the same preferred axis. The plane wave reflection and transmission characteristics of a planar interface between free space and a general uniaxial medium have been obtained; since application as a polarizer is envisioned, the preferred axis lies in a plane parallel to the interface. Application of the Brewster law, as well as conditions for total reflection are explored.

ISSN:0950-0340    

DOI:10.1080/09500349114550651

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In order to protect them from environmental degradation, as well as to increase their reflection efficiency in some instances, metallic gratings are often coated with dielectric materials. This practice introduces the effects of waveguide modes in the reflection characteristics. Here, we study the alteration of the plane wave reflection characteristics of a perfectly conducting grating whose grooves are filled up to the brim by a dielectric material. The method of analysis is synthesized from an improved T-matrix method. From the numerical results for sinusoidal gratings, it is shown that the dielectric material in the grooves does affect the reflection characteristics; however, the effect of waveguide modes is avoided.

ISSN:0950-0340    

DOI:10.1080/09500349114550661

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We report an analysis of the dynamic response of a fibre optic ring resonator when the resonator loop is phase modulated sinusoidally. It is shown that whenfmτ, the product of the modulating frequency (fm) and loop delay time (τ), becomes greater than certain value (in the range of 0·0004 to 0·06 that depends on the finesse of the ring) the response of the FORR deviates from steady state response. Experimental results are given to verify the theoretical analysis.

ISSN:0950-0340    

DOI:10.1080/09500349114550671

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A microscopic quantum description of the interaction between a radiation field coupled to sources and linear passive optical systems is presented. The quantum input-output relations for correlation functions that determine the quantum statistical properties are established under general conditions. In particular the influence of the vacuum field is taken into account. The treatment has advantageously been performed with the help of Green function techniques, which allow one to include loss mechanisms and dispersion of the linear medium. To illustrate the general results two interesting examples, the diminishing of squeezing due to a lossy Fabry-Perot interferometer and the action of a black screen, are given.

ISSN:0950-0340    

DOI:10.1080/09500349114550681

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The fully-coupled Jaynes-Cummings model contains both counter-rotating and rotating wave terms. It is usual to solve for the rotating wave dynamics exactly and to include the counterrotating contributions as a perturbation. In this paper we choose an alternative approach in which the counterrotating terms are treated exactly and the rotating wave interaction is included as a perturbation. We find that, under the influence of the counterrotating terms, the fieldQ-function undergoes an oscillatory bifurcation in phase space. The cycle-averaged splitting of theQ-function is found to be of the same order in the interaction as the Bloch-Siegert shift.

ISSN:0950-0340    

DOI:10.1080/09500349114550691

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Using the virtual mode theory for attenuated total reflection (ATR) experiments the long-range coupled-surface modes supported by symmetrically bound thin films have been examined to study the influence of prism coupling. Approximate analytic results show that in certain circumstances prism coupling may result in adecreaseof mode loss from the unperturbed eigenvalue. This is well illustrated for the long-range surface exciton-polariton. Detailed numerical evaluations confirm the analytic results. The generally accepted conclusion that prism coupling always results in an increase in mode loss is thus not supported by these results which show convincingly that for more complex ATR geometries simplistic treatments are invalid.

ISSN:0950-0340    

DOI:10.1080/09500349114550701

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The description and demonstration of a short-time approximation method are presented for solution of the Heisenberg equation using a computer for operator algebra symbolic computation to obtain an operator series. Multimode nonlinear processes can be studied by this method in a fully quantum way; the symbolic operator or standard numerical results as well as the graphical dependences can be computed.

ISSN:0950-0340    

DOI:10.1080/09500349114550711

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor