An ultrastable laser as an optical frequency standard

Abstract

After more than half a century as primary frequency standard caesium clocks have exhausted their potential to improve their stability. Therefore, a replacement by a new standard that is even more precise is imminent. The potential successor standards are optical clocks, which use energy level transitions that produce electromagnetic waves in the optical regime of the frequency spectrum. These optical clocks achieve significantly higher stabilities than cesium standards (relative uncertainty of10−18 vs. 10−15). One of the main components of such a clock is a laser with a very narrow line width. In the framework of the EMPIR project “Coulomb Crystals for Clocks” (CC4C), the Federal Office for Metrology and Surveying (BEV) acquired such a laser as a first step towards the operation of an optical clock in Austria. Furthermore, as part of the project, the installation of a fiber optic connection from Vienna to Brno was initially evaluated and, in the further course of the project, it was also established in order to be able to carry out a comparison measurement of the ultra-stable laser at the BEV with its counterpart of the “Institute of Scientific Instruments” (ISI) in Brno. After a short introduction to the matter, this thesis deals with the characterization of the laser’s drift behavior, frequency stability, the cavity’s zero-crossing temperature and the creation of an uncertainty budget. The collected data includes results from comparison measurements with the ISI in Brno.