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40m Log |
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Tue Feb 2 18:35:47 2016, gautam, Update, Green Locking, Lightwave NPRO moved from PSL table to SP table
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Tue Feb 2 18:54:02 2016, Koji, Update, Green Locking, Lightwave NPRO moved from PSL table to SP table
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Wed Feb 3 23:23:47 2016, gautam, Update, Green Locking, Lightwave NPRO moved from PSL table to SP table 
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Thu Feb 4 09:16:46 2016, Koji, Update, Green Locking, Lightwave NPRO moved from PSL table to SP table
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Fri Feb 5 00:23:01 2016, gautam, Update, Green Locking, Lightwave NPRO moved from PSL table to SP table   
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Fri Feb 5 16:50:24 2016, gautam, Update, Green Locking, First pass at mode-matching   
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Mon Feb 8 15:36:37 2016, gautam, Update, Green Locking, Alternative mode-matching scheme
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Tue Feb 9 04:37:10 2016, ericq, Update, Green Locking, Laser swap initiated
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Tue Feb 9 11:49:47 2016, gautam, Update, Green Locking, Laser swap initiated
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Tue Feb 9 19:15:36 2016, gautam, Update, Green Locking, Laser swap - updates 
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Wed Feb 10 17:57:15 2016, gautam, Update, Green Locking, Laser swap - updates
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Fri Feb 12 17:05:40 2016, gautam, Update, Green Locking, Laser swap - green light recovered but no flashes in the arm
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Fri Feb 12 19:07:52 2016, Koji, Update, Green Locking, Laser swap - green light recovered but no flashes in the arm
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Fri Feb 19 00:42:19 2016, gautam, Update, Green Locking, Laser swap - beam ellipticity from laser?  
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Mon Feb 22 13:56:52 2016, gautam, Update, Green Locking, Laser swap -reflected beam from ETM aligned
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Tue Feb 23 23:01:16 2016, gautam, Update, Green Locking, Laser swap - Green PDH locking 
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Wed Feb 24 19:29:13 2016, gautam, Update, Green Locking, Laser swap - Green PDH locked
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Fri Feb 26 01:52:44 2016, gautam, Update, Green Locking, Laser swap - Green PDH OLTF
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Mon Feb 29 17:17:26 2016, gautam, Update, Green Locking, Laser swap - still no green beatnote
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Wed Mar 2 17:42:19 2016, gautam, Update, Green Locking, Laser swap - some progress
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Thu Mar 3 01:25:50 2016, gautam, Update, Green Locking, Laser swap - 2 IR + 1 green beatnotes found
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Fri Mar 4 01:11:41 2016, gautam, Update, Green Locking, Laser swap - both green beatnotes found
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Sat Mar 5 23:31:01 2016, gautam, Update, Green Locking, Laser swap - some updates    
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Mon Mar 7 23:51:36 2016, gautam, Update, Green Locking, Laser swap - some improvement   
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Tue Mar 8 18:22:20 2016, rana, Update, Green Locking, Laser swap - some improvement
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Message ID: 11988
Entry time: Fri Feb 12 17:05:40 2016
In reply to: 11985
Reply to this: 11989
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Author: |
gautam |
Type: |
Update |
Category: |
Green Locking |
Subject: |
Laser swap - green light recovered but no flashes in the arm |
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After carefully tweaking the mode-matching of the IR into the crystal and the four-axis translation stage on which the doubling oven is mounted, I managed to recover 800uW of green power going into the green Faraday. Considering we have ~225mW of IR power coming out of the IR faraday (and roughly that amount going into the SHG crystal), I'd say this is pretty consistent (if not slightly better) with a recent power budget I had made for the X end. The amount of green power we get out of the doubling crystal is very sensitive to the alignment of the crystal to the beam axis. I suspect we could improve the situation slightly if the mode-matching lenses were mounted on translational stages so we could tweak their position, but the current situation on the X endtable does not provide space for this. In any case, I'd say we are at least as good as we were before, and so this should be an adequate fix until the new end-table is installed (though I don't know why we aren't seeing the predicted SHG conversion efficiency of 3-4% as predicted by Kiwamu's calculations, we are getting more like .36% conversion efficiency)...
Because the alignment of the beam before the doubling oven had changed, I had to adjust the steering mirrors to make the green beam go into the green faraday. I had placed a couple of irides for the green beam as a reference of the old path into the arm, and I used these to adjust some of the green mirrors to center the green beam on these. However, I did not observe any flashes in the arm. I will check if we are still mode-matched to the arm, and if the lenses downstream of the doubling oven need to be moved.... |