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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: 12009
Entry time: Wed Feb 24 19:29:13 2016
In reply to: 12006
Reply to this: 12012
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Author: |
gautam |
Type: |
Update |
Category: |
Green Locking |
Subject: |
Laser swap - Green PDH locked |
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After the discussion at the meeting today, I decided to try and lock the green by sweeping through PZT dither frequencies in the vicinity of 200kHz without worrying about the AM/PM ratio for now. I was able to lock the PDH loop relatively quickly, at an empirically determined PZT dither frequency of 213.873kHz, 2Vpp (the amplitude was copied from the value at the Y-end). For today's efforts, I borrowed the sum+HPF pomona box from the Y-end, I will make a replica given that we are using Lightwave lasers at both ends now. After adjusting the PZT sliders and lenses on the translational stages at the endtable to maximize the green transmission as best as I could, I was able to get GTRX up to about 0.07 - this is far off from the value of ~0.25-0.3 I seem to remember us having with the old setup, even though we have more green light into the arm cavity. I will take a measurement of the loop transfer function to see what sort of bandwidth we have... |