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Entry  Wed Apr 10 12:17:34 2019, Anjali, Update, 2micronLasers, Intensity noise stabilization of 2 micron source 2_micron_setup.jpgLaser_chara_setup.pngLaser_characteristics.pdfAOM_chara_setup.pngAOM_characteristics.pdf
    Reply  Wed Apr 10 18:58:48 2019, rana, Update, 2micronLasers, Intensity noise stabilization of 2 micron source 
       Reply  Wed Apr 24 09:01:49 2019, Anjali, Update, 2micronLasers, Intensity noise stabilization of 2 micron source Intensity_stabilisation.png
Message ID: 2328     Entry time: Wed Apr 24 09:01:49 2019     In reply to: 2325
Author: Anjali 
Type: Update 
Category: 2micronLasers 
Subject: Intensity noise stabilization of 2 micron source 

Attachment #1 shows the schematic of the experimental setup for amplitude stabilization using AOM. The proposed idea is as follows

  • The output power from the  Zeroth order port of the AOM depends on the RF power supplied to the AOM and the  RF power from the RF driver is dependent on the input voltage to the driver. 
  • When amplitude of the laser chnages to due to amplitude noise, the output from photodiode will also changes. The output of one of the photodiodes is connected through a gain element (G) to the RF driver of AOM. So, when PD output changes , the gain of the gain element should be adjusted such that the input voltage to the AOM driver changes and thus the RF power which affect the output power from the AOM. 
  • The gain element could be SR560 (I still have to understand more about it) and the photodiodes that we have are thorlabs DET10D detector which are DC coupled. We also need additional TIA stage after the PD. There were two of them built by the summer student. We tested both and one of them only works fine now.

OK...but how will the amplitude stabilization be done? How about a diagram showing the feedback loop and electronics?

  1. what is the feedback circuit?
  2. Can it drive the low impedance of an AOM driver?
  3. What is the photodiode?
  4. It has to be an AC coupled feedback (DC coupled is always terrible).
  5. What is the requirement on the intensity noise as a function of frequency?

[Aidan, Anjali]

  • Attachment #1 shows the cleaned up setup for  2 micron experiment


Attachment 1: Intensity_stabilisation.png  77 kB  Uploaded Wed Apr 24 10:02:53 2019  | Hide | Hide all
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