Ground-based gravitational-wave detection: now and future

In the past three years, the first generation of large gravitational-wave interferometers has begun operation near their design sensitivities, taking up the mantle from the bar detectors that pioneered the search for the first direct detection of gravitational waves. Even as the current ground-based interferometers were reaching their design sensitivities, plans were being laid for the future. Advances in technology and lessons learned from the first generation devices have pointed the way to an order of magnitude improvement in sensitivity, as well as expanded frequency ranges and the capability to tailor the sensitivity band to address particular astrophysical sources. Advanced cryogenic acoustic detectors, the successors to the current bar detectors, are being researched and may play a role in the future, particularly at the higher frequencies. One of the most important trends is the growing international cooperation aimed at building a truly global network. In this paper, I survey the state of the various detectors as of mid-2007, and outline the prospects for the future.