Laser interferometer gravitational-wave detectors——hearing aids for human on deep universe

Gravitational wave was detected for the first time 100 years after Einstein's prediction.Here we briefly describe the advanced laser interferometer gravitational-wave observatory (advanced LIGO), with which the discovery was made. The emphasis is put on the optical and laser technology of the detector. Laser interferometer gravitational-wave detectors are fundamentally Michelson interferometers. The original Michelson interferometer helped disproving the existence of "luminiferous aether", which led to the development of the theory of relativity. And laser technology,for which Einstein established the foundations with the theory of stimulated emission, has played crucial role in detecting gravitational waves. Besides LIGO, there are other ground or space based laser interferometer gravitational-wave detectors, which are in the process of building and designing. All those detectors will make joint observation and locate the sources of the waves,and extend the detectable spectrum of gravitational waves. It is believed that this detection is the beginning of a new era of the gravitational wave detection technology and gravitational wave astronomy.