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Entry  Fri Dec 27 16:26:11 2019, Yehonathan, Update, PSL, PMC Linewidth measurement PMCTransmissionSpectra.pdf
    Reply  Wed Jan 1 14:14:00 2020, Yehonathan, Update, PSL, PMC Linewidth measurement 150MHzSideBandCreation.pdfLinewidthMeasurment.pdf
       Reply  Wed Jan 15 15:04:31 2020, gautam, Update, PSL, PMC Linewidth measurement 
          Reply  Fri Jan 17 22:11:19 2020, Yehonathan, Update, PSL, Ringdown measurements 20200117_192455.jpg20200117_192448.jpg
             Reply  Sat Jan 25 11:54:42 2020, Yehonathan, Update, PSL, Ringdown measurements Input_beam_path.jpgReflected_Beam_Path.jpgTransmitted_Beam_Path.jpgPMCRingdownNormalizedRawdata.pdfTransPDFits.pdf
                Reply  Mon Jan 27 21:35:06 2020, Yehonathan, Update, PSL, Ringdown measurements IMC_REFL_Beam_Path.jpg
                   Reply  Mon Jan 27 21:48:49 2020, gautam, Update, PSL, Ringdown measurements elevatedSeis.pdf
                      Reply  Tue Jan 28 16:01:17 2020, gautam, Update, IOO, IMC WFS servos stable again QPD_recenter.png
                         Reply  Tue Jan 28 20:51:37 2020, Yehonathan, Update, IOO, IMC WFS servos stable again 
                            Reply  Wed Jan 29 12:40:24 2020, Yehonathan, Update, IOO, IMC Ringdowns preliminary data analysis IMCRingdownNormalizedRawdata.pdfIMCTransPDFits.pdf
                               Reply  Mon Feb 3 13:54:10 2020, Yehonathan, Update, IOO, IMC Ringdowns extended data analysis IMCTransReflAnalysis_anotated.pdf
                                  Reply  Wed Feb 5 21:13:17 2020, Yehonathan, Update, IOO, IMC Ringdowns extended data analysis 
                                     Reply  Sat Feb 15 12:56:24 2020, Yehonathan, Update, IOO, IMC Transfer function measurement IMCFrequencyResponse.pdfIMCRingdownNormalizedRawdata.pdfIMCREFLPDFits.pdf
Message ID: 15109     Entry time: Wed Jan 1 14:14:00 2020     In reply to: 15106     Reply to this: 15126
Author: Yehonathan 
Type: Update 
Category: PSL 
Subject: PMC Linewidth measurement 

Turns out the 35MHz sidebands are way too weak to resolve from the resonance when doing a PZT scan.

I connect the IFR2023B function generator on the PSL table to the EOM instead of the FSS box and set it to generate 150MHz at 13dbm.

To observe the resulting weak sideband I place a PDA55 at the peak-off path from the transmission of the PMC where there is much more light than the transmission of the PMC head mirror. Whoever is using this path there is a PD blocking it right now.

I do a PZT scan by connecting a triangular signal to the EXT DC on the PMC servo with and without the EOM (Attachment 1). A weak sideband can clearly be spotted now.

Using the above 150MHz sideband calibration I can find the roundtrip time to be 1.55ns.

I take a high-resolution scan of a resonance peak and fit it to a Lorentzian (Attachment 2) and find a roundtrip loss of 1.3%.

Using the above results the cavity decay time is 119ns.

We should investigate what's going on with the ringdown measurements.

Attachment 1: 150MHzSideBandCreation.pdf  85 kB  | Show | Hide all | Show all
Attachment 2: LinewidthMeasurment.pdf  63 kB  | Hide | Hide all | Show all
LinewidthMeasurment.pdf
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