Objective: [In continuation to elog 3177]

1. Measuring ringdown decay time

Details:

1. The new RF switch's output was attached to AOM. The diffraction efficiency remained the same as noted previously, i.e. 57% (as mentioned in 3131)

2. The PD used at the transmitted path is  PDA20CS-EC (see elog 3139 for properties). The PD at the transmitted beam is set with a 10dB attenuator.

3.  The amplitude of TEM00 mode in the transmitted signal was 4V. The demodulation phase was set to 185º. The mode matching was observed to be 4.88/(4.88+1.82)=72%

4. The filter cut-off frequency was 3 Hz and the gain was 100. 

5. The laser temperature was 8400±20. The offset voltage varied from -1 to -0.8. 

6. The cavity was able to lock the TEM00 mode (see Fig 1). The voltage of the RF switch control was set to low to cut off the input to AOM. The possible fitting obtained gives a decay time of 1.45 µs (see Fig 2)