Rb Polarization Depends on Direction of Magnetic Field #11
Description
Since the Rb Spin Filter was first implemented, we have observed an asymmetry in the rubidium polarization we can achieve with the two types of circular polarization. When Munir observed this, he attributed it to a viewport which transmitted the two types of circularly polarized light differently. We have since replaced this viewport, but still do not achieve equal rubidium polarizations.
I would like to get to the bottom of this phenomenon, and the first step is to collect data to determine conclusively if the viewport contributes to the differences in polarization. We will achieve this by determining if the viewport alters the polarization state of the pump laser when it is present in the system. We will determine this by measuring the degree of circular polarization of the pump laser in three different situations.
- With the viewport in and the magnetic field oriented parallel with the laser propagation direction.
- With the viewport in and the magnetic field oriented anti-parallel with the laser propagation direction.
- With the viewport out.
We will determine the degree of circular polarization using the "Ken retro-reflection method" where the laser is reflected back on itself and the intensity is measured as a function of the QWP position. The closer the intensity gets to zero at whatever position of the QWP, the better circularly polarized our light is.
@nstamos20, I'd like for you to collect this data.