The year 2015 has been designated by the United Nations General Assembly as the International Year of Light and Light-based Technologies. An extensive series of events involving many thousands of academic institutions and private sector partners around the world has celebrated the importance of light in our everyday lives, in modern technology and for future and emerging technologies. The year 2015 is also the anniversary of a number of significant historical events, some of which literally changed the world in which we live. In 1015 Ibn Al-Haytham published his Book of Optics, which is now recognised to have had major influence on the development of optics in Europe over the following 400 years. In 1815, Fresnel first proposed the notion that light is actually a wave. This concept was then firmly established 150 years ago by Maxwell and his electromagnetic theory of light propagation. In the words of Einstein, “one scientific epoch ended and another began with James Clerk Maxwell”. Not many years followed and Einstein published in 1905, another anniversary, his discovery of the photoelectric effect demonstrating that light is made of photons. In 1915 Einstein then published his general theory of relativity, possibly the most celebrated and grand theory in physics in which light plays a central role. In this School we attempted to give a broad and modern overview of the field of optics in a series of lectures that address ongoing topics of research. Nonlinear optics has played a central role in science since the invention of the laser in 1960 that gave us access for the first time to intense and coherent light that could excite the nonlinear response of various materials. The range and breadth of applications of nonlinear optics is staggering, ranging from simple green laser pointers to highly advanced, new-generation X-ray lasers and particle accelerators. In these lectures a number of topics are covered including long-range propagation of extreme intensity light pulses in air, supercontinuum generation with applications for example in the understanding oceanic rogue wave events, and photon-pair creation on micro-photonic chips for the next generation of quantum communication devices. Light is also a unique investigation tool that can provide insight into some of the deeper questions of modern physics, such as the role of symmetries in the universe. It can also be used to study peculiar solutions to the equations of quantum mechanics and this gave rise to the fertile field of Airy beams that propagate along curved trajectories. Optical beams can carry not only spin but also orbital angular momentum. The discovery of this remarkable additional degree of freedom is changing the way in which we think, for example, about optical communication systems, particle trapping or manipulation and quantum information encoding.
Finally, light is of course all about our ability to see the world. Detection and imaging are therefore at the forefront of modern optics and in our lectures we saw talks on fascinating and remarkable topics such as cloaking, weak measurements whereby photons are measured without actually perturbing their state, high resolution 3D imaging that is performed using a camera made from only one single pixel and new developments in “ghost” imaging that allows us to see even if the light never actually interacts with the object that we want to image.
A unique feature of this volume is that each chapter has been prepared as a collaboration between students at the school and the lecturers. We feel that this approach to prepare proceedings from schools such as this one has been very successful and a model for the future. We must thank all authors and lecturers for the effort devoted to the careful preparation of the individual chapters.
Acknowledgements go also to the local organisers, Barbara Alzani and Marta Pigazzini who, through their enthusiasm make the Enrico Fermi Summer Schools such unique events and to Monica Bonetti and Marcella Missiroli from the editorial/production office of the Italian Physical Society. Finally, we thank the Italian Physical Society for making this event possible.
D. Faccio, J.Dudley and M. Clerici