During the last week of September, the Infrared Mode Cleaner has been assembled in clean room using the same screw size used for the Green Mode Cleaner ( a bit different than the design due to availabililty and to avoid breaking).

To differenciate the 2 modes cleaner, one can look to the BMC connector : the blue one corresponds to the infrared and the yellow one to the green.

We might still need to make a holder for the BMC as we did for the green mode cleaner to avoid stress on the wires.

We were able to test this mode cleaner on the infrared path on the table and found a finesse of the order of 280 below the expected value given by the mirrors reflectivity (we expect between 312 and 520).

This might come from power and temporal fluctuations. We could see these fluctuations while testing the green mode cleaner but we were suspecting that they came from the power fluctuations coming from the SHG cavity.

These 2 fluctuations are reduced if we have more sampling points.

They are also reduced if the ramp frequency sent to scan the piezo actuator is reduced ( we could see a better stability by reducing the frequency from 20Hz to 5Hz).

We could also see some temporal shift between the ramp and the mode cleaner transmission.

It seems that this is due to some low pass filtering of the piezo driver because this shift can be seen between the output of the piezo driver and its monitoring output.