STAGE Frequency-doubling of a picosecond frequency-comb laser for atom interferometry

Light-pulse atom interferometry, where light pulses are used as atom beam splitters, has led to extremely sensitive and accurate quantum sensors that can be used to perform very stringent tests of fundamental physics such as: testing the equivalence principle, detecting gravitational waves, probing short-range forces or measuring fundamental constants (e.g. Newton’s gravitational constant or the fine-structure constant). Until recently, light-pulse atom interferometry had only exploited continuous-wave (cw) laser sources. We have recently demonstrated atom interferometers where the beam splitters are realized with pulsed lasers, or more specifically frequency-comb lasers [1]. This major achievement, which we obtained in the visible spectrum on rubidium (Rb) atoms, paves the way for extending light-pulse interferometry to other wavelengths (e.g. deep-UV to X-UV) and therefore to new species, since one can benefit from the high peak intensity of the ultrashort pulses which makes frequency conversion in nonlinear media efficient.
Our team is currently working along two lines of research which aim at: 1) pushing the limits of frequency-comb-driven atom interferometry (FCAI) and 2) extending FCAI to other wavelengths. In particular, we are currently designing and building a new experimental setup to cool and trap ytterbium (Yb) atoms, and perform FCAI on their 6s2 1S0 6s6p 1P1 transition around 399 nm.