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Message ID: 82     Entry time: Mon Mar 1 17:52:46 2010
Author: Tara Chalermsongsak 
Type: Laser 
Category: RC noise 
Subject: New Result 

I got a quarter wave plate from Greg Ogin this afternoon. The attached plots show:

black-> RC noise when there are no quarter wave plates. It's the beat of circularly pol beams.

green-> when one wave plate is intalled.(from last week)

Blue-> two wave plates are in used. I'm surprised that nothing changed much from green.

Red-> I use the Buzby box to amplifie the demodulated signal and connect it to SR560 for filtering. The SR560 complains about overloading signal when I

set gain at 1, but it's ok when gain is 2.

It seems still far from noise budget Rana gave me. The peak around 1000 Hz might to be investigated.

Attachment 1: Mar01_RCnoise.png  11 kB  | Hide | Hide all
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