Interferometric gravitational wave detectors

This talk has to dwell on the current technical state and prospects rather than discoveries. The search for gravitational waves began J. Weber's initial experiments using resonant acoustic bar detectors. These detectors now much improved by advances in transducer technology, better seismic isolation and operation at cryogenic temperatures have attained rms strain sensitivities of h≅ 10-18 in few Hertz wide bands in the 1 kHz region and offer at present, the best chance for the direct detection of gravitational radiation. This overview deals mainly with detectors comprised of free masses sensed by optical interferometry which are being constructed. These are designed to have a high sensitivity over a large detection bandwidth, 10Hz to 10kHz. (author)