Abstract
An atomic clock is one which provides the most accurate definition of the second, and is thus the most important one that exist on Earth. It symbolizes universal time. A tender was launched in 2007 by the European Space Agency (ESA) for the development of a miniature atomic clock in embedded systems (first of all for the satellites and after that for the public), with low energy consumption. The project, funded at a half-million, was begun in October 2007 and could allow some new applications for these ultra accurate clocks. Three laboratories of the Institute for micro technology at the University of Neuchatel won the project and are therefore responsible for this achievement. You should know that a first prototype of such a clock was made in 2004 with the project HORACE. A part of this clock, that helps to reduce the weight and size of the system, is the use of laser cooling atoms of Cesium 133, of which I am going to introduce the principle.
