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Entry  Tue Mar 8 06:29:06 2011, kiwamu, Update, Green Locking, Intensity noise setup 
    Reply  Wed Mar 9 04:46:13 2011, kiwamu, Update, Green Locking, more intensity noise measurement intensity_setup.pngIntensityNoise.png
       Reply  Wed Mar 9 18:17:11 2011, kiwamu, Update, Green Locking, Intensity noise coupling diff_noise.pngIN_TF.png
          Reply  Thu Mar 10 14:06:54 2011, kiwamu, Update, Green Locking, Intensity noise limits the beatnote sensitivity diff_noise_Mar8.pngIN_TF_complete.png
             Reply  Thu Mar 10 14:22:58 2011, kiwamu, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                Reply  Thu Mar 10 14:29:05 2011, Koji, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                Reply  Thu Mar 10 14:30:53 2011, rana, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                   Reply  Thu Mar 10 16:00:53 2011, Aidan, Joe, Update, Green Locking, Intensity stabilization loop using beatnote DC. P1000313.jpgP1000314.jpgP1000315.jpgGREEN_ISS_LOOP.pdfScreenshot-C1ALS_OVERVIEW.adl.png
                      Reply  Thu Mar 10 21:45:34 2011, rana, Update, Green Locking, Intensity stabilization loop using beatnote DC. 
Message ID: 4389     Entry time: Wed Mar 9 04:46:13 2011     In reply to: 4383     Reply to this: 4392
Author: kiwamu 
Type: Update 
Category: Green Locking 
Subject: more intensity noise measurement 

 

Here is a diagram for our intensity noise coupling measurement.

intensity_setup.png

 

The below is a plot for the intensity noise on the DCPD. (I forgot to take a spectra of the PD dark noise)

For some reason, the RIN spectrum becomes sometimes noisier and sometimes quieter. Note that after 10 pm it's been in the quiet state for most of the time.

An interesting thing is that the structure below 3 Hz looks like excited by motion of the MC when it's in the louder state.

IntensityNoise.png

Quote: from #4383

A photo diode and an AOM driver have been newly setup on the PSL table to measure the intensity noise coupling to the beat note signal.

We tried taking a transfer function from the PD to the beat, but the SNR wasn't sufficient on the PD. So we didn't get reasonable data.

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