High-energy neutrino astronomy: detection methods and first achievements

In the last century, astronomy evolved from optical observation to the multi-wavelength study of celestial objects from radio waves up to x-and gamma-rays, leading to a wealth of new discoveries and opening the way to high-energy astroparticle physics. In particular, the recent success of ground-based very-high-energy gamma-ray telescopes has opened a new window on the most powerful and violent objects of the Universe, giving a new insight into the physical processes at work in such sources. In the context of high-energy astronomy, neutrinos constitute a unique probe since they escape from their sources, travel undisturbed on virtually cosmological distances and are produced in high-energy hadronic processes. In particular they would allow a direct detection and unambiguous identification of the sites of acceleration of high-energy baryonic cosmic rays, which remain unknown. This report discusses the physics potential of the domain and reviews the experimental techniques relevant for the detection of high-energy (>= TeV) neutrinos. The results obtained by the first generation of such detectors are presented, along with the perspectives opened by new projects and prototypes being currently developed.