Description
In our group, we are interested in $^6$Li$^{40}$K molecules at their rovibrational ground-state, which posses a large $3.6~\text{Debye}$ absolute dipole moment. This makes them suitable for the quantum many-body simulation of anisotropic and long range interactions. In order to transfer the molecules from a weakly bounded Feshbach-state to their ground-state, the method to be used is stimulated raman adiabatic passage (STIRAP). Excessive residual laser phase noise will drive unwanted transitions and therefore decrease the STIRAP efficiency. To deal with this issue, we extended the length (from 2 cm to 20 cm) of our external cavity diode lasers to narrow the free-running linewidth. The phase noise measurement method consisted in recording the spectral noise density of the beat note produced between the laser and a high-finesse cavity filtered version of itself. The integrated phase noise was reduced from 200 mrad to 40 mrad.
Theoretical calculations of the STIRAP efficiency also show the critical dependence on the pulse duration. The stochastic nature of the phase noise means that to reduce its effect, the pulse duration should be reduced. But on the other hand one should consider that the pulse should not be too short such that the adiabaticity criterion is violated. Additionally, we included tapered amplifiers to increase the Rabi frequency while preserving the low phase noise of the long external cavity diode lasers.
| Presenter name | Victor Avalos Pinillos |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
