Optical clocks are the most precise measurement devices built to date. At present, optical clocks reach instabilities in the range of 10^-16 in 1 sec averaging time and uncertainty on the order of 10^-18. The performance of optical clocks surpasses the traditional microwave clocks and will lead to a new definition of the SI second in the future.
Optical clocks allow improving practical applications such as the dissemination of a frequency standard over optical networks and via satellite transmission. This allows making accurate comparisons between remote clocks and improving satellite based navigation and geodesy mapping. Already now the optical clock accuracies enable to differentiate the gravitational red-shift over a few centimeters of height.
Furthermore, these mind-boggling accuracies open new possibilities for testing fundamental physical theories and determining the values of fundamental constants. Exotic searches may also be performed by such clocks, e.g. they are already being suggested as tools in the search for dark matter. It is not beyond reason to suspect that in the future such clocks will also lead us to a better understanding of what time is.
In BGU we are in the advanced stages of building an optical clock based on ¹⁷¹Yb atoms trapped in an optical lattice. This project is in collaboration between the BGU Atom Chip group and INRIM, the Italian institute of standards.