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Message ID: 389     Entry time: Mon Jan 30 04:38:14 2012
Author: Giordon Stark 
Type: DailyProgress 
Category: Coating Q 
Subject: Calculated Noise Measurements of Photodiodes, Preamp Setup 

Attached a lot of things - the PDF contains an updated list of parts with links to part specifications. We're still missing information (or would like more information) about the following parts that we currently have:

  • vacuum
  • polarizing beam splitter
  • QWP and HWP

The PDF also describes the calculated noise shown in ComparisonOfNoise.png. We found that the noise expected from each photodiode is 7.6e-8 -- coming out of the preamp would have a noise of 7.6e-8 * sqrt(2) [factor from the combination of the input photodiode signals]. Everything seems to be on the up and up - but I will talk with Zach (and Rana if he's around) about what we've got here.

Talked with Zach after everything on Friday - here's a brief discussion of what we talked about on the whiteboard using markers that contained all the colors of the rainbow.

  • Step 1: Once we get the ESD and the sample, we're going to look at the output and compare it with the drive frequency so that we expect to see oscillations
  • Step 2: Then, we'll excite the sample and then let it decay and observe a decaying sinusoidal on the oscilloscope
  • Step 3: Then, we'll add in the lock-in amplifier and tune it so that we effectively chop off most of the signal (in a perfect case, we see no more sinusoidals, and simply just a decay curve)
  • Step 4: ???
  • Step 5: Win a senior thesis


Attachment 1: NFLR.png  4 kB  | Hide | Hide all
Attachment 2: NOLSR.png  4 kB  | Hide | Hide all
Attachment 3: PDA36A.png  4 kB  | Hide | Hide all
Attachment 4: LaserNoiseComparison.png  5 kB  | Hide | Hide all
Attachment 5: LaserNoiseResiduals.png  5 kB  | Hide | Hide all
Attachment 6: ComparisonOfNoise.png  6 kB  | Hide | Hide all
Attachment 7: ExperimentalSetup.pdf  250 kB  Uploaded Mon Jan 30 05:52:18 2012  | Hide | Hide all
ExperimentalSetup.pdf ExperimentalSetup.pdf ExperimentalSetup.pdf ExperimentalSetup.pdf ExperimentalSetup.pdf
Attachment 8: ExperimentalSetup.png  49 kB  Uploaded Mon Jan 30 05:52:27 2012  | Hide | Hide all
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