Analysis of the PZT scan / TF data taken on May 31st and Jun 1st.
Each PZT was shaken with 10Vpp 1Hz triangular voltage to the thorlabs amp.
The amp gain was x15. Abut 4 TEM00 peaks were seen on a sweep between 0 and 10V.
The input voltage where the peaks were seen was marked. Each peak was mapped on the
corresponding fringe among four. Then the each slope (up and down) was fitted by a iiner slope.
Of course, the PZTs show hystersis. Therefore the result is only an approximation.
PZT1: PZT #26, Mirror C6 (CM1)
PZT2: PZT #23, Mirror C5 (CM2)
PZT arrangement [ELOG Entry]
Ramp Up 13.21nm/V
Ramp Down 13.25nm/V
Ramp Up 13.23nm/V
Ramp Down 13.29nm/V
=> 13.24+/-0.02 nm/V
Ramp Up 13.27nm/V
Ramp Down 12.94nm/V
Ramp Up 12.67nm/V
Ramp Down 12.82nm/V
=> 12.9+/-0.1 nm/V
The OMC cavity was locked with the fast laser actuation. Each PZT was shaken with a FFT analyzer for transfer function measurments.
(No bias voltage was given)
The displacement data was readout from the laser fast feedback. Since the UGF of the control was above 30kHz, the data was
valid at least up to 30kHz. The over all calibration of the each curve was adjusted so that it agrees with the DC response of the PZTs (as shown above).
The response is pretty similar for these two PZTs. The first series resonance is seen at 10kHz. It is fairly high Q (~30).