TRIENNIAL REPORT OF THE ICO TO IUPAP FOR 2002-2005

Introduction

ICO, the Place where the World of Optics meets, this is the vision statement proclaimed at the ICO Bureau Meeting 2002 in Florence. However, the worldwide scientific exchange did change drastically after September 11, 2001, under the influence of the restrictions on travelling, visa and scientific publications introduced by the US Department of Treasury Office of Foreign Assets Control (OFAC) and the US Departments of State and Homeland Security. Thanks to joint political actions of some of our US based international society member with other US academic and scientific institutions, these sanctions have been partially released since their initial introduction. Besides political also economical and commercial events have significantly marked the optics community: the decline of the information technology boom and its consequences for the optical telecommunication industry. However, the role of optics as an interdisciplinary and enabling field of science and technology has been proven by its contributions to the development and success of the emerging fields of nanoscience, in the control of feature sizes smaller than micrometers and the manipulation of individual objects such as atoms and molecules, and the most challenging domains of the life sciences, including biology and medicine. The explosive growth of optics and photonics as a major technical field positively influencing our quality of life as well as being an economic stimulus has continued during the first years of the 21st Century.

Optics as a branch of science and technology has changed considerably since the creation of the ICO in 1947 and, while remaining a branch of physics, it now encompasses fields of science and engineering that directly address the needs of society and development, and this in a scientifically and technically quite sophisticated way. For this reason and for the interdisciplinary aspect of optics as an enabling field of science and technology, ICO has applied now for the status of an ICSU international scientific associate, at the same time wishing to retain its status as an IUPAP Affiliated Commission. We hope that this application will be received favourably by the ICSU and supported positively by the IUPAP.

The main objective of ICO remains: Global Promotion of Optics, as stated in article 1 of the statutes. The strength of ICO is the nearly complete global coverage by its Territorial Committee Members and the affiliation to the International Union of Pure and Applied Physics (IUPAP), and through IUPAP to the International Council for Science (ICSU). The weakness of ICO is the lack of individual members and the very limited financial resources ($33,000/year).

ICO activities, 2002-2005

Within this triennium the ICO continued to fulfil its mission to contribute, on an international basis, to the progress of the science of Optics and its applications following the lines established by its Long range planning committee, as reported in the green book "Towards ICO-19", June 2002. In particular, the ICO promotes international co-operation and facilitates the rapid exchange of information, by encouraging and furthering the organization, on an international basis, of scientific meetings and summer schools. It emphasizes actions for the education and training in Optics internationally. It develops special actions for the development of Optics in regions where particular support is needed. It strives to improve the recognition of Optics as a field of science with a significant impact on economy.

With the admission of 3 new Territorial Committee Members (Estonia, Latvia, Lithuania), 2 new International Society Members (LAM: African Laser, Atomic, Molecular and Optical Sciences Network and OWLS: Optics within Life Sciences) and 3 new Associated Members (Greece, Tunisia, Morocco) and the geographical distribution of the Bureau members (Argentina, Canada, China, Finland, Germany, Israel, Italy, Japan, Korea, Poland, Senegal, Spain, Switzerland, The Netherlands, USA) the ICO has further improved global coverage on the possibilities to fulfil its mission. To further improve the exchange of information between the ICO Bureau and the Territorial Committee Members, each elected Vice-President has been asked to accept responsibility for personal and regular contacts with about 6 Territorial Committees. Every Territory has now a direct contact with at least one member of the ICO Bureau.

In addition to its Triennial Congress, which was organized in August 2002 at Florence, Italy, the ICO initiated again international topical meetings and acted as a cosponsor for a number of international scientific meetings organized by other bodies. In the last three years, ICO participated or was associated with a total of 21 scientific meetings and schools, of which 8 in Europe, 5 in Asia, 3 in the USA and Canada, 3 in Latin America, and 2 in Africa. With the selection of Chanchung as the location for its next Triennial Congress, 21-26 August 2005, on "Challenging Optics in Science and Technology", the ICO wants to support and emphasize the importance of China as a rapidly developing country, both economically and scientifically.

Most activities have been focused on two priority areas: developing nations, and education and training in optics. The long standing collaboration with the ICTP, the Abdus Salam International Center for Theoretical Physics in Trieste, was continued and even intensified by participation in the newly founded TSOSA Advisory Group. TSOSA stands for "Trieste System for Optical Sciences and Applications". The mandate of this Advisory Group is to create actions on Optics and Photonics in developing countries, proposing subjects for future Winter Colleges, training courses of ICS, Sandwich programs, and in general, external activities relevant to the Trieste System to be exported to developing countries. The members of TSOSA Advisory Group are representing IAEA, ICO, IEEE/LEOS, OSA, OWLS, SPIE, UNESCO, and the Trieste System itself. They will meet every year during the Winter College on Optics in Trieste. The topics of these Winter Colleges were 2003 "Optics in the Life Sciences", 2004 "Interferometry and its Applications to Modern Physics", and 2005 "Nanophotonics". On these occasions the ICO/ICTP Awards for outstanding young scientist conducting research in a developing country were handed over to the Laureates.

In order to support the development of optics in Latin America, the ICO Bureau had its annual meeting at the RIAO/OPTILAS 2004 conference in Porlamar, Venezuela, preceded by a conference on "Optics, Life and Heritage" in Havana, Cuba. The Galileo Galilei Award winner 2003 was invited at Porlamar to present his outstanding contributions to the field of Optics, which he had accomplished following the rules of this Award under comparatively unfavourable circumstances. A report on Optics in Latin America was already published in the ICO Newsletter January 2003.

The ICTP sponsored African Laser, Atomic and Molecular Physics and Optics network, LAM, is now an International Society Member of ICO. Important events were the LAM-6 and LAM-7 Workshop, 2002 in Tunis and 2004 in Duala, Cameroon, respectively. The Moroccan Society of Optics did organize a School of Lasers, in December 2003 at Tangier, with participants from the Maghreb, Egypt and Senegal. ICO is also associated with the African Laser Center (ALC) initiative of the South African government. The intention of this initiative is to assist in the development of several optics centers around the African Continent allowing for equipment sharing and operations at different locations.

For the Regional Development of Optics ICO has continued a proceedings donation programmed for libraries in developing countries and an invited lecturer programmed covering partial expenses for guest lecturer in regions of the world requesting special support. In collaboration with OSA and SPIE there have been activities for distributions of educational kits available in English, Spanish and French. An equipment donation program for developing countries is also under discussion. However, to ensure feasibility the problems of customs have to be solved as well.

One of the most significant conferences supported by ICO in collaboration with SPIE and OSA are the Conferences on Education and Training in Optics and Photonics (ETOP), whose eighth edition convened during 2003 in Tucson, Arizona. This meeting was devoted in large part to sharing information and concepts which are of potential use in growing a credible workforce both at the technician and professional levels, a major area of endeavour by ICO.

The ICO was alerted in an official letter by the Iranian Territorial Committee to the impact of the sanctions introduced by US, concerning US international societies, for which scientists from certain countries (as Iran) were not admitted for regular membership and suffered restrictions on travelling, visa and scientific publications. Copies of this letter were sent to the representatives of our US based international society members OSA. SPIE and IEEE/LEOS, as well as to the IUPAP representative. To the present time, no satisfactory answers were received. Nevertheless, thanks to joint political actions with other US academic and scientific institutions addressed to the US Government, these sanctions have been partially released since their initial introduction. The ICO Bureau insists on the fact that all members of the International Council for Science (ICSU) accept the basic principle of the universality of science, which affirms the right and freedom of scientists to associate in international scientific activity without regard to such factors as citizenship, religion, creed, political stance, ethnic origin, race, colour, language, age or sex. Such rights are embodied in a variety of articles in the International Bill of Human Rights.

The General Assembly of the ICO has appointed its Bureau to apply for the status of an ICSU International Scientific Associate. After some informal contacts during the last few years, the ICO Bureau has now finalized the application. It has been deposited and received by ICSU in February 2005, supported by an extensive document describing optics as a branch of science and engineering with interactions both within physics and outside physics. Most of the ICO members, as well as the majority of scientists and engineers working in optics, identify themselves more directly with optics as a field than with optics as a part of physics. Optics plays also an important role in chemistry, biology and medicine. We believe, that it is therefore appropriate that optics be recognized within ICSU as an interdisciplinary field of its own right.

The ICO decided at its Bureau meeting in Porlamar, to contribute to the World Year of Physics 2005 with a joint action of all its Members. The main goals of this action are to

• emphasize the importance of Optics as a branch of Modern Physics
• give the ICO, the place where Optics meets, world wide visibility

We will announce all ICO sponsored and endorsed conferences in 2005, in particular the ICO-20 conference, as events of the WYP2005. We encourage all our Members to declare and announce optics events as a contribution of Optics to the WYP2005. In particular, this request is addressed to our Territorial Committees for their local optics events to promote Optics as an important branch of modern physics throughout the world, including the developing countries. For this purpose the ICO has created a joint logo of ICO and WYP2005.

The ICO website has additional information on its activities and the ICO Newsletters, published quarterly.

About Optics in 2004

(Extracted from reports for IUPAP and ICSU prepared by Pierre Chavel)

While a number of neologisms such as photonics, optronics, optoelectronics have appeared to describe activities closely related to optics, it should be made clear from the outset that Optics is taken here in its broadest sense, defined as "the field of science and engineering encompassing the physical phenomena and technologies associated with the generation, transmission, manipulation, detection and utilization of light and extending on both sides of the electromagnetic spectrum as far as the same concepts apply". One measure of its relevance in the context of world Science is the large number of scientific periodicals dedicated to pure and applied optics and its relation to interdisciplinary fields in science and technology. Moreover, Optics extends nowadays from X-rays and even gamma rays to the very long wave of interest in radioastronomy.

Stepping back to embrace a global view of the field, lessons from the past may be helpful. In 1948, the founders of International Commission on Optics selected for discussion at their first technical meeting such topics as the accommodation of the human eye and its resolving power, the combination of aberrations and diffraction, the design of microscope objectives, interferometers for testing camera lens aberrations, elements of thin film design, diffraction gratings, and new inorganic and polymer glasses. To many, optics is still encompassed by such a set of topics. Yet, when comparing this list with the scope and state of the art of optics today, two major facts appear quite conspicuously.

Firstly, it is indeed true that there has been progress in all of these fields, notably in the following ways:

• The human eye optics is being investigated by adaptive optical systems, where a deformable mirror compensates the aberration of ophthalmic media to focus and scan a diffraction limited spot on the retinal cells. Whether adaptive optics will ever be fitted to our spectacles and provide diffracted limited imaging to everyone is a meaningful open issue.
• The most complex optical systems ever built provide f: 0.5 diffraction limited imaging at ultraviolet wavelengths over several square centimetres for the replication of computer chip masks. Thin films can be designed and fabricated in stacks of nearly one hundred layers to match virtually every conceivable spectral reflectance profile, covering not only the visible, near infrared, thermal infrared and near ultraviolet parts of the spectrum, but the extreme ultraviolet in the 5 through 60 wavelength nm range (20 through 250 electron-volts), which is expected to be of relevance to future lithography systems.
• Interferometers are available in all sizes from submicron Fabry Perot cavities of interest in telecommunication optics to gravitational wave sensors with kilometres long arms. Diffraction optics has evolved from gratings into holography and lens achromatisation. Micro-opto-electro-mechanical systems (sometimes called MOEMS) offer, as an example, Michelson interferometers for Fourier transform spectroscopy integrated in square millimetres. On the theoretical side, progress on the relation between the emission of light and coherence has been significant with the recent understanding of the role of surface waves and near field effects in the spatial and temporal coherence of thermal sources.
• Optical materials extend beyond glasses to include non-linear crystals, rewritable holographic materials such as photo-refractive crystals, liquid crystals and polymer light emitting diodes. The latter might well invade our daily life for a better energy yield and a longer lifetime of our lamps. At its turn, new hybrid organic-inorganic optical materials are certainly promising for near future optical computing technologies.
• Ten meter mirror telescopes, always fitted with adaptive optics facilities to compensate for atmospheric turbulence, combine their images coherently over distances larger than 100 m. In 2003, some of the first images from the European Southern Observatory "Very Large Telescope" in Chile provided clear and nearly direct evidence of a black hole in the very centre of our galaxy through analysis of the motion of the visible stars closest to it. Planets outside the solar system are now counted by three digit numbers: even larger optical arrays are currently at the planning stage with the hope to provide evidence of terrestrial planets where life may exist in a form similar to ours. In these technologies, adaptive optics is now playing a leading role for image quality improvements in astronomical image techniques, by correcting the undesirable influence of the terrestrial atmospheric turbulence on image formation astronomical systems.

Secondly, optics now encompasses much more than its content at that time: completely new domains have arisen. In 1948, nobody predicted the advent of the laser that was to occur just twelve years later, or the key role that optics plays in present information systems and in particular telecommunication. Imaging below the standard diffraction limit and into the nano-world seemed impossible. By emphasizing these aspects in the following sections, we shall undoubtedly fall short of many forthcoming revolutionary changes, but we shall illustrate the new interactions between optics and various other branches of science and engineering, concluding with its relevance to life sciences.

Lasers:

The diversity of lasers is an indication of their wide variety of uses, ranging from basic science to many branches of engineering. We shall examine just a few.

Extremely short pulses have reached the range of attoseconds, at least through nonlinear transients in high power femtosecond pulses. The latter, when obtained through carefully designed mode locking, have shown unexpected reproducibility and offer the promise of the most accurate clock ever thought of, down in the 16 significant digit range.

Cold atom experiments and the rise of atom optics, a new field of physics which was recognized by the 1997 Nobel Prize in Physics being awarded to S. Chu, C. Cohen-Tannoudji and W. Phillips, rely in part on the mature state of laser instrumentation. Appropriate cooling and trapping drives sets of atoms to the coherent state of Bose Einstein condensates, where all atomic wave functions widely overlap and all atoms are in the same quantum state. "Atomic lasers" derived from such condensates by allowing a small leak through a radio wave frequency magnetic transition, now a research tool, may some day turn into the ideal source for single atom nanosciences. At this time, cold atoms provide by far the most sensitive gyroscopes, with industrial applications in sight.

Information Optics:

For some time, the prospect of optical computers competing with electronic computers was a favourite topic in popular sciences magazines. In a much more mature way, the role of optics in information technology has now been developed and is still developing in directions where the low interaction between photons and the large bandwidth available around optical carriers are best exploited, opening a field now designated by specialists as "Information Optics".

Optical telecommunications, currently the standard for all long-distance data and voice transmissions, directly derive from those arguments. Materials improvements in the absorption and dispersion of optical fibres led to the first optical communication links around 1980. The replacement of multimode fibres by monomode fibres allowed reduced dispersion and better signal quality. The advent of fibre amplifiers around 1990 provided an efficient way to increase the optical telecommunication bandwidth. Further progress arose around 2000 from the simultaneous transmission of several signals coded on different wavelength channels in one fibre ("wavelength division multiplexing"), giving access to demonstrated capacities in the range of terabits per second (equivalent to about hundred millions of telephone conversations) on one single cable.

Compact disk memories are another clear case of the interaction of optics with other fields of science and engineering, in this case materials science, mechanics and microelectronics, to produce a high-tech product line with significant consequences on economy and society. Optics in the current compact disk is involved in focusing and tracking. Reading head optics have undergone a miniaturization that pioneered micro-optics in commercial systems. Materials science contributed write-once and rewritable media as well as wide gap semiconductors to reduce wavelength and thereby increase the diffraction limited information density.

Optics and the nano-world:

There seem to be three, not completely identical, definitions for the use of the prefix "nano" in relation with physical objects. One is the control of feature sizes smaller than micrometers by some specified arbitrary amount. The second is the investigation of effects that show up only at length scales smaller than some physical parameter typically in the nanometre to micrometer range. The third pertains to the manipulation of individual objects, usually atoms and molecules. Occasionally, controversies arise between advocates of the various definitions. However, 2004 optics is involved in all three cases.

It is well known that colour interference effects appear for optical path delays on the order of micrometers, that gratings show widely dispersed spectra of visible light when their spatial frequency reaches hundreds of lines per millimetre, and that butterfly and bird wings with complex submicrometer structures show striking bright colours whose full understanding is still progressing. However, the fabrication of 1D, 2D and 3D diffraction gratings, thin film layers, planar waveguides, and indeed semiconductor layers of characteristic dimensions smaller than micrometers has developed dramatically in the recent years.

One major effect involved in structures smaller than the wavelength of the illuminating light is the optical near field, i.e. the combination of evanescent waves needed to fulfil Maxwell's equations in such objects. Their control through computer modelling, through adequate fabrication tools, and their investigation by near field optical microscopy techniques are all recent achievements of optical science. Indeed, realizing that optical imaging could exceed the standard diffraction limit by exploring objects at a sub-wavelength distance from their surface came as a revolution to many.

Finally, manipulating single atoms and single molecules through their fluorescence properties or in optical tweezers is characteristic of the current trend of nano-optical research.

Optics in life sciences:

In many respects, the recent progress of Optics in domains such as those mentioned above bears implication to life sciences way beyond standard microscopy. Indeed, the term "biophotonics" has been coined recently, not as much to designate a separate new branch of science as to testify of the fact that there is considerable room for progress of optics before all its potential application to life sciences have been taken to fruition.

While standard microscopy has reached its diffraction limit for decades, many microscopy techniques have been developed to better suit the needs of biology and acquire data that were previously not accessible. These include fluorescence microscopy, multiple photon fluorescence microscopy, confocal microscopy, Raman microscopy. Sophisticated fluorescent techniques are being used both for biological research and are likely to become standard diagnosis procedures. Individual molecules or markers are readily accessible to fluorescence imaging.

An additional important imaging modality, applicable to organs and other strongly diffusive media, is optical coherence tomography, now already a commercial standard for retina imaging, where the data of interest are sliced by their interference contrast with a reference.

René Dändliker, President ICO