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 Wed Jul 23 22:34:07 2008, Yoichi, Update, LSC, Arm cavity g-factor measurement
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 Thu Jul 24 01:27:00 2008, Koji, Update, LSC, Arm cavity g-factor measurement
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Thu Jul 24 02:57:26 2008, rob, Update, LSC, Arm cavity g-factor measurement
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Thu Jul 24 08:09:26 2008, Yoichi, Update, LSC, Arm cavity g-factor measurement
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Message ID: 731
Entry time: Thu Jul 24 02:57:26 2008
In reply to: 730
Reply to this: 733
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| Author: |
rob |
| Type: |
Update |
| Category: |
LSC |
| Subject: |
Arm cavity g-factor measurement |
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| Quote: |
So, now I feel that the method for the TEM01 quest should be reconsidered.
If we have any unbalanced resonance for the phase modulation sidebands, the offset of the error signal is to be observed even with the carrier exactly at the resonance. We don't need to shake or move the cavity mirrors.
Presence of the MC makes the things more complicated. Changing the frequency of the modulation that should go throgh the MC is a bit tricky as the detuning produces FM-AM conversion. i.e. The beam incident on the arm cavity may be not only phase modulated but also amplitude modulated. This makes the measurement of the offset described above difficult.
The setup of the abs length measurement (FSR measurement) will be easily used for the measurement of the transverse mode spacings. But it needs some more time to be realized. |
We should be able to see 166MHz sideband resonances using the double demodulated photodetectors. With these, the 33MHz sidebands will be acting as LO when the 166MHz sideband (or mode) resonates. Some modeling may be necessary to determine if the SNR will be good enough to make this worthwhile, however. |