[Jeff, Zach, Lisa, Koji]
Gluing of the cavity mirrors went very well!!!
Preparation
- Checked if the cavity is still resonating. => Yes.
- Checked the FSR: 264.251MHz => 1.1345m
2.5mm too long => Move each micrometer by 0.625mm backward
- FSR&TMS (I)
Aligned the cavity again and checked the FSR: 264.8485MHz => 1.13194m
TMS(V): 58.0875MHz => gamma_V = 0.219324
TMS(H): 58.1413MHz => gamma_H = 0.219526
the 9th modes of the carrier is 9.7-10.4 line width (LW) away from the carrier resonance
the 13th modes of the lower f2 sideband are 9.2-10.2 LW away
the 19th modes of the upper f2 sideband are 0.3-1.8 LW away
We found that this coincidence of the resonance can be corrected by shortening the cavity round-trip by 0.5mm
- Spot positions (I)
The spots on the curved mirrors were ~1mm too much inside (FM side). In order to translate the cavity axis,
MM2 and MM4 were pushed by θ
θ/2.575 = 1mm ==> θ = 2.6 mrad
The separation of the micrometers are ~20mm
d/20mm = 2.6mrad ==> d = 52um
1div of the micrometer corresponds to 10um => 5div = 50um
- Move the micrometers and adjusted the input steering to recover the alignment.
- In any case we were confident to adjust the FSR/TMS/spot positions only with the micrometers
BS1/FM1/FM2 gluing
- Aligned the cavity
- Glued BS1/FM1/FM2 one by one while the cavity resonance was maintained.
FM2 was slipping as the table is not leveled well and the fixture was not supporting the optic.
- FSR&TMS (II)
FSR: 264.964875MHz => 1.13144m (Exactly 0.5mm shorter!)
TMS(V): 58.0225MHz => gamma_V = 0.218982
TMS(H): 58.1225MHz => gamma_H = 0.219359
the 9th modes of the carrier is 10.3~11.7 LW away
the 13th modes of the lower f2 sideband are 7.4~9.3 LW away
the 19th modes of the upper f2 sideband are 1.5~4.4 LW away
- Spot positions (II)
Looked OK.
CM2 gluing
- Glued CM2. The mirror was supported from the back with allen keys.
- FSR&TMS (III)
FSR: 264.9665625MHz => 1.13144m
TMS(V): 58.1275MHz => gamma_V = 0.219377
TMS(H): 58.0813MHz => gamma_H = 0.219202
the 9th modes of the carrier is 10.2~10.9 LW away
the 13th modes of the lower f2 sideband are 8.5~9.4 LW away
the 19th modes of the upper f2 sideband are 1.4~2.7 LW away
- Spot positions (III)
Looked slightly off at CM2. Pushed MM2 by 4um.
CM1 gluing
- Glued CM1.
- FSR&TMS (IV)
FSR: 264.964875MHz => 1.13144m
TMS(V): 58.06625MHz => gamma_V = 0.219145
TMS(H): 58.08625MHz => gamma_H = 0.219220
the 9th modes of the carrier is 10.8~11.1 LW away
the 13th modes of the lower f2 sideband are 8.2~8.6 LW away
the 19th modes of the upper f2 sideband are 2.6~3.2 LW away
- Spot positions (final confirmation)
Looked OK.
Final measurement
- After everything was finished, more detailed measurement has been done.
- FSR&TMS (final)
FSR: 264.963MHz => 1.13145m
TMS(V): 58.0177MHz => gamma_V = 0.218966
TMS(H): 58.0857MHz => gamma_H = 0.219221
the 9th modes of the carrier is 10.8~11.7 LW away
the 13th modes of the lower f2 sideband are 7.3~8.6 LW away
the 19th modes of the upper f2 sideband are 2.6~4.5 LW away
Final values for the micrometers
- MM1: The one closest to the input mirror (CM1) 0.78mm
- MM2: The other one on CM1 0.89
- MM3: The one closest to the output mirror (CM2) 0.90
- MM4: The other one on CM2 0.90
/------------\
0.90 0.78
\------------/
0.90 0.89
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