This Volume originates from the lectures delivered at the CL Course of the “Enrico Fermi” School, which was held in Varenna from June 25 to July 5, 2002. The purpose of the course was to give an overview of the physics of artificial semiconductor structures confining electrons and photons. The study of the light-matter interaction in this kind of systems is relevant both to fundamental Solid State Physics and to related fields like Quantum Optics. Furthermore, it furnishes the background for several applications in particular in the domain of optical devices, lasers, light-emitting diodes or photonic crystals. In recent years the research in this field has focused on the electronic and optical properties of confined semiconductor structures like Quantum Wells, Quantum Wires, Quantum Dots and semiconductor microcavities. In this context, several exciting effects have been observed. In particular, we mention the effects related to the microcavity polaritons, which are mixed electromagnetic radiation-exciton states inside a semiconductor microcavity.

The study of the characteristics of such states, besides a wide interest by itself, shows strong relations with the domain of cavity quantum electrodynamics and thus with the investigation of some fundamental theoretical concepts. Also topics like the exciton localization due to disorder or the coherent control of optical pulses emitted by confined structures belong to the subjects which are considered in the domain of semiconductor confined structures. The emission characteristics of low-dimensional systems like Quantum Wells, Quantum Wires and Quantum Dots are of enormous importance for the development of new types of semiconductor lasers and light-emitting diodes. These topics were presented during the Course by a team of very distinguished lecturers, whose contributions to the physics of confined electrons and photons have been seminal.

The basic theoretical tools relevant to the field have been introduced by G. Bastard in his lecture on the quantum mechanics of semiconductor nanostructures. S. Koch and B. Jusserand lectured on the semiconductor Bloch equations and on the electron-phonon interaction in semiconductor nanostructures, respectively. Optical crystals were the argument by the lectures of P. S. J. Russell. The concept and the physics of polaritons in quantum wells and microcavities were introduced in the lectures by C. Andreani and J. Baumberg. The link between confined semiconductor physics and quantum optics has been established in the lectures by E. Giacobino on quantum optics in semiconductor nanostructures and in that by J. Ryan on squeezing in non-linear waveguides. Effects of disorder on the optical properties of confined systems was treated in the lecture by V. Savona, coherent control in that by D. Citrin, whereas ultrafast dynamical effects were presented by T. Elsässer. C. Piermarocchi and C. Ciuti presented elements of spintronics in their lectures on quantum computing with spin-polarized excitons and on dynamics and imprinting of electron spin in semiconductors, respectively. One- and zero-dimensional confinement have been the subjects of the lectures by E. Kapon (Semiconductor quantum wires) and D. Bimberg (Semiconductor quantum dots). Lasing in low-dimensional systems and quantum cascade lasers were presented by D. Oberli and by C. Gmachl, respectively. C. Weisbuch gave in his lecture an overview on devices based on confined semiconductor systems.

The Course was attended by a large number of students from all over the world, who followed the lectures with great interest and assiduity. They had the opportunity to present their research work in two poster sessions, which were very successful. Thanks to the enthusiasm of the lecturers and of the participants, we found again the friendly and exciting atmosphere we enjoyed years ago as students in Villa Monastero. We take the occasion to warmly thank everybody. However, the Course had never been successful without the precious help of the team of the Società Italiana di Fisica including Barbara Alzani, Marcella Missiroli, Ramona Brigatti, Franca Sabadini, Marta Pigazzini and Guglielmo Comini. We particularly appreciated the friendly support of the president of the Società Italiana di Fisica Franco Bassani. Finally we kindly acknowledge the financial support of the Società Italiana di Fisica, the European Community and the Ecole Polytechnique Fédérale de Lausanne.

B. Deveaud, A. Quattropani and P. Schwendimann