Journal of Optics

The authors recall the basic principles and advantages of the ring laser gyro (RLG) which is the most widely developed of all optical gyroscopes based on the Sagnac effect. The main error sources which can affect RLG performances are discussed, and among them gas flows in the active medium and frequency synchronisation of counterpropagating waves or 'lock-in'. Particular attention is given to locking phenomenon: the predominant influence of mirrors backscattering is emphasized and means devised to overcome this problem are explained. Some important design rules used in the RLG construction are defined. Two representative examples of RLG for different applications are described including the triaxial RLG in a single optical block.

Examines the diffraction and the free propagation of an optical scalar field by means of the Fresnel approximation. In a unified way, deduces its properties from the differential equation of paraxial waves. By means of the variable separation method, one can obtain directly significant field distributions like: pseudoplane waves, pseudospherical waves and Gaussian beams. The following topics are also treated: the Fresnel diffraction integral, inverse propagation, the Fresnel transformations, some invariant properties for affinity transformations, and formulas which permit an evaluation, in every point of the field, of the distribution of the error connected to the Fresnel approximation.

Institute of Physics Publishing is pleased to announce the merger of two current optics titles, Journal of Optics (formerly Nouvelle Revue d'Optique) and Pure and Applied Optics. The new journal, to be titled Journal of Optics A: Pure and Applied Optics, will cover all aspects, both theoretical and experimental, of modern and classical optics. It is intended that this merger will unite the editorial strengths of each journal, eradicate overlap, and create a strong platform for the development of a world-class optics journal.

In conjunction with this merger, Quantum and Semiclassical Optics is to be relaunched under the new title Journal of Optics B: Quantum and Semiclassical Optics. Journal of Optics, comprising parts A and B, will be an integral part of Institute of Physics Publishing's dedicated optics programme.

A feature of these journals has always been strong European support, and we are delighted to confirm that Journal of Optics will be the official journal of the European Optical Society (EOS). Each title will consist of six bi-monthly issues, published in A4 format, beginning with the first issue of Journal of Optics A in January 1999, and Journal of Optics B in the following month. Subscribers to these journals will receive all the benefits that Institute of Physics Publishing journals offer; full text electronic access including six-year archives, a thirty-year abstract archive and new Hypercite ^TM citation linking.

Both titles will begin under new Editorship, and we would like to take this opportunity to thank Professor Boccara, Professor Bertolotti and Professor Mandel for their achievements during their respective terms of office. We hope that both journals will continue in the tradition of excellence that has been established through their efforts.

In association with the changes outlined above, all editorial processing will be transferred to the main Institute of Physics Publishing offices. Our special thanks go to Françoise Chavel and Michèle Bouchareine at the EOS offices in Paris for their hard work and important contribution over recent years.

All new submissions should therefore be sent directly to:

Publishing Editor Journal of Optics Institute of Physics Publishing Dirac House Temple Back Bristol, BS1 6BE United Kingdom

We are also pleased to introduce electronic submission for both titles. Please refer to Notes for Authors for full details.

At the end of the year I retire as Editor-in-Chief of Journal of Optics, a position that I have held for seven years.

It is my pleasure to thank all the authors who provided the journal with the results of their creative research in optics. We obviously rely to a large degree on a steady flow of good quality contributions.

The number and quality of the papers published in the journal has clearly improved over the years, and the audience, mainly French at the beginning, is now truly international.

I would also like to thank Miss Sophie Demonchaux for her invaluable help in the management of our journal.

It would have been nice for me to finish by saying a lot of good things about the field of optics and its bright future, but sadly, this autumn, the world of optics is poorer for the loss of two people who have contributed actively in this field. Our thoughts go to Professors Christian Imbert and Serge Lowental from the Institute of Optics in Orsay, France, and we hope that a future issue of the journal may be able to pay tribute to their scientific lives.

Finally I wish that the merger of Journal of Optics with Pure and Applied Optics will result in an optics journal to meet the needs of the whole European scientific community.

A C Boccara

A new method for determining Brewster's angle is proposed based on the effect that the phase difference produced by a simple reflection from the test medium, for a two-frequency circularly polarized light source, is exactly equal to zero when the incident angle equals Brewster's angle. Its best resolution is deg and the validity of the method was demonstrated.

A partir de l'optique de Fourier, nous étudions les caractéristiques d'un dispositif optique permettant de modifier en temps réel la répartition d'énergie d'un faisceau laser de puissance et faisons des comparaisons avec les mesures expérimentales. Les effets thermiques induits durant le traitement superficiel sont aussi étudiés théoriquement.

In this work we have studied the damaging effect of laser light on cell membranes using single bilayer liposomes as a model system. Liposomes, because of their structural similarities to membranes of biological cells, are the best model systems used for the investigation of the effect of laser radiation on biomembranes. Samples of liposomes were routinely prepared and stained in our laboratory. For efficient localized heating of the membrane by laser light, we stained liposomes with a membrane dye with strong absorption at the laser wavelength. Irradiated by the laser beam, the membrane breakdown occurred at a particular laser power for samples of stained liposomes. The laser-induced damage was detected with the use of a photon correlation technique. The power threshold for this damage was measured.