The measuring of small periodic displacements (with amplitudes million times smaller then the dimensions of the atoms) today is widely used for a number of fundamental and practical problems such as detection of gravitational waves, noncontact measuring of surface acoustic waves, nondestructive testing, photo-acoustic microscopy and spectroscopy and many others. From all of them the possibility with precise laser interferometer to detect gravitational waves, generated from a number astrophysical objects and universe phenomena such as binary stars oscillations, birth and collapse of neutron stars, black holes and so on is strongly distinguished because of its fundamental value. Gravitational waves, according to theory of relativity change periodically the metrics of the space and cause simultaneously periodical contractions and expansions of the physical objects in each other perpendicular directions. With multi-beam interferometer and power high stable laser these small periodical variations (which depends on the intensity of the gravitational wave) one can transform into a weak alternative light flux, detected with high sensitive photo-electronic techniques. At present several key projects for detection of gravitational waves with multi beam interferometers such as LIGO (Laser Interferometer Gravitational-Wave Observatory) – a common project of the California Institute of Technology and the Massachusetts Institute of Technology from the USA, VIRGO - a common project of French and Italian scientists, TAMA – of Japanese scientists, GEO600 – a common project of German and English scientists, ACIGA (Australian Consortium Interferometric Gravitational Wave Astronomy) – of the scientists from Australia and New Zeeland and others united the efforts of the scientists for discovering of the gravitational waves. A picture from the airplane as an example for the scale of such projects of the both mutually perpendicular arms, each 3 kilometers long of the laser interferometer, build in Cascina, Italy is shown on the left. The interferometer's arms represent tunnels, which of the example of the picture are with mean radius of 1,2 meters. A high vacuum in the tunnels to avoid the light Relley scattering from the molecules of the gaze is maintained. A picture of the LIGO-interferometer at Hanford with arm length of 4 kilometers is shown on the right. Other similar interferometer is build in Livingston and is predicted both to work synchronously to eliminate the different noise sources, as for example the accidentally local vibrations of the earth surface with seismic or another character. Special fundaments and ant-seismic techniques are applied in the places, where the sensitive elements of the multi-beam interferometer are set up. An art - photo for the work and spirit in such scientific laboratory is shown at the next figure on the left.
The information about the universe is obtained mainly trough electromagnetic waves untill now . The detection of the gravitational waves will give the humanity totally new and universal tool for the investigation of the universe and its evolution. The setting of such high purpose today is a natural result of the progress of the applied physics and especially from the possibility of measuring of very small periodical displacements – a million times smaller then the dimension of the building particles of the atoms. At the other hand this put another fundamental question as well – about the structure of the micro-space.
The three my publications, listed below demonstrate experimentally the possibilities of measuring very small periodical displacements with laser interferometer. In the first paper at 1974 for the first time from me is discussed the possibility for using the laser interferometer for detection of gravitational waves and in the last - are analyzing details and experimentally is proved such possibility.