27 October 2021
- Schematic view of the vacuum system of the clock.
This project is aiming at developing a new atomic clock based on an optical transition of mercury atoms. Some properties of mercury are similar to these of other atoms considered for atomic clocks such as calcium, strontium or ytterbium, especially the existence of an optical transition with a very narrow natural linewidth. One advantage of mercury is the existence of six abundant and therefore usable isotopes, including two fermions and four bosons. Another advantage is related to the ten times smaller value of one of the most bothersome systematic perturbation (frequency shift due to ambient blackbody radiation) compared to the above mentioned atoms. Mercury atoms will be captured and cooled in a magneto-optical trap followed by an optical lattice. Using atoms that are strongly confined in an optical lattice eliminates several concerns related to the atomic motion. One of the specific aspects of this mercury optical lattice clock is the use of several innovating laser sources in the ultraviolet domain (notably 254nm for the laser cooling and 266nm for the clock transition).
- Laser source at 254nm for lasercooling.
This project is aiming at developing a new innovating optical atomic clock with accuracy below 1 part in 10-17. This clock will be compared to other atomic clocks (strontium optical lattice clock, rubidium and caesium fountains) through an optical frequency comb delivered by a femtosecond laser. These comparisons will lead to new tests of fundamental physical laws (Equivalence Principle) and will contribute to the quest for a unified theory of gravity, electroweak and strong interactions. With accuracies below 10-17, atomic clocks could have new applications such as Earth gravitational field mapping based on measurements of the gravitational red shift (Einstein effect).
Contact
Sébastien Bize
- Email: Sebastien.Bize (at) obspm.fr
- Tel.: +33 (0) 1 40 51 20 97