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Entry  Wed Dec 15 11:26:39 2010, frank, tara, Notes, BEAT, cleaning optics to get rid of scattering light clean_2010_12_15.jpgbeat_2010_12_15.png
    Reply  Fri Dec 17 02:23:38 2010, frank, tara, Notes, BEAT, cleaning optics to get rid of scattering light clean_2010_12_16.jpgbeat_2010_12_16.png
Message ID: 431     Entry time: Wed Dec 15 11:26:39 2010     Reply to this: 433
Author: frank, tara 
Type: Notes 
Category: BEAT 
Subject: cleaning optics to get rid of scattering light 

We are cleaning optics to reduce possible scattering light sources. Optics behind PMC are quite dusty. Improvement in the beat measurement was observed during the process, the

actual data is yet to be measured.


 Dirty optics might cause the beam to scatter, and the scattered light could end up in the RFPD for PDH locking. Its random phase will

mess up the error signal causing extra noise in our measurement. So we try to clean the optics and see if we can improve our measurement.


The circled optics in the picture are cleaned already. Aligning and optimizing is yet to be done.

Red plot was taken today after cleaning a few lens, blue plot was taken after cleaning all the lens shown in fig1.

Although blue curve has higher noise upto 200 Hz, this might come from beam misalignment after removing lens for cleaning.

I'll try to re configure gain setup to see improvement.


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