40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  ATF eLog  Not logged in ELOG logo
Entry  Fri Jul 16 19:23:27 2010, Alastair, Laser, Fugly, noise measurement of locked cavity freq_noise.pdfnoise_from_locked_cavity.mat
    Reply  Mon Jul 19 13:34:39 2010, Zach, Laser, GYRO, noise measurement of locked cavity 
Message ID: 856     Entry time: Fri Jul 16 19:23:27 2010     Reply to this: 858
Author: Alastair 
Type: Laser 
Category: Fugly 
Subject: noise measurement of locked cavity 

 This is the noise of the cavity if we just lock the laser to the cavity using the fast actuator (no slow actuation) and look at the control signal to the laser.  I used a potential divider to reduce the voltage going to the spectrum analyser (I used 1.023kOhm and 9.32kOhm to give approx 10 times reduction).

The plot here is taking the V/rt(Hz) and multiplying it back up again to the full voltage, then converting to frequency using the piezo spec from the laser spec sheet of 4.11471MHz/V.

We maybe want to plot this on the main noise plot to see how far away we are from measuring a useful mirror displacement noise, so I have included the .mat file that I used to make the plot

Attachment 1: freq_noise.pdf  22 kB  Uploaded Fri Jul 16 20:26:24 2010  | Hide | Hide all
Attachment 2: noise_from_locked_cavity.mat  14 kB  Uploaded Fri Jul 16 20:26:41 2010
ELOG V3.1.3-