[Marc, Mitsuhashi, Rishab, Shalika]

Summary of these past days activities as elog was down.

Preparation of optical table and rack

We moved the table away of TAMA AS vacuum chamber and installed a spare rack we found in TAMA north arm.

We setup Manuel's PC there with all appropriate softwares. It is now connected by Ethernet to the FC new DGS switch.

Optical setup and camera test

We installed a second f=50mm lens roughly 100 mm after the first one to have a collimated beam.

Then, we installed a 10:90 BS so to have about 6 mW in reflection.

We measured the beam diameter to be about 800 um and quite well collimated.

In the reflection, we installed a QWP and HWP mounted in motorized mounts.

Finally, we installed our polarization camera (PAX1000IR2) several tens of cms after to have some space for our future tests.

As expected from the datasheet, we can measure the polarization rotation or retardation with accuracy of 0.5 deg. This is same order of magnitude of our currents birefringence characterization setups (both from NAOJ or ICRR)!

We could confirm that the rotation of QWP and HWP yield the expected ellipticity and rotation changes respectively.

We then applied continuous rotation of QWP and HWP with a 5:6 Lissajous pattern.

Fig 1 shows a screenshot of the camera software during this measurement where you can see the polarization state, Poincare sphere, Stokes parameters and ellipticity/rotation angles.

For now, we can save several parameters in csv and in figure 2 you can see the time evolution of some of them.

Check of LC

Finally, we wanted to install our 2 LCs.

We found that one of them is likely broken as it can not be recognized from the temperature controller out of the box.

We are in contact with Thorlabs to solve this issue