We found out that the TAMA 1 fast axis orientation was also quite uniform and similar to the aztec sample...

Following entries will report all measurements that were taken but here we report the various checked performed :

- with 14.7 mW input power and OD 2 the maximal power reaching the QPD was below 0.6 mW (maximum recommended by Thorlabs)

- the output voltage of the QPD with this optical power is about 1.4 V (consistent with the responisitivty of the QPD at 1064 nm)

- to avoid saturation of the lockin amplifier (at 1V) we placed 6dB attenuator and the lockin voltage was indeed divided by 2

- the spectrum of the signal show clearly the peak at the chopper frequency and harmonics (note that 3rd harmonic is stronger than 2nd)

- the beams alignment before the QPDs were tuned to always be inside the sensor with and without sample

- the 2 QPDs signals have the expected behavior when changing the input beam polarization angle

- the maximum of the QPDs with sample correspond to about 0.9 of the maximum without sample (consistent with sample reflectivity checked with power meter)

- for the last measurement (will be precised in the entry) we reduced the incident power to 0.588 mW, removed the OD and the laser linewidth to avoid as much as possible possible back-scattering and recentered the beam with and without sample before every measurement