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Entry  Tue Dec 4 19:34:22 2018, awade, DailyProgress, WOPO, Diabolo 532 nm power drop and retuning 18-12-04_DiaboloInside_annotate.jpegplot20181204_DiaboloSHGRaligned1064nm.pdfplot20181204_DiaboloSHGRErrSig.pdf20181204_RetuneDiaboloSHGAlignment.zip
    Reply  Thu Dec 6 20:04:50 2018, awade, DailyProgress, WOPO, Diabolo 532 nm power drop and retuning 
       Reply  Fri Dec 7 20:31:06 2018, awade, DailyProgress, WOPO, Diabolo: cleaning dust out of SHG unit, self heating issues 18-12-07_20-06-46_4774.jpg18-12-07_20-06-58_4776.jpg18-12-07_20-07-44_4780.jpgIMG_4785.JPGIMG_4766.MOV
          Reply  Thu Dec 13 14:01:13 2018, awade, DailyProgress, WOPO, Diabolo: contacted coherent 
             Reply  Thu Dec 13 16:24:06 2018, awade, DailyProgress, WOPO, Diabolo: baseline numbers for coherent plot20181218_PhaseMatchingCurveFastScanDiaboloSHG.pdf20181213_SHGScanWithLNTempTuning.zip
                Reply  Wed Dec 19 16:48:18 2018, awade, DailyProgress, WOPO, Diabolo: baseline numbers for coherent 
                   Reply  Thu Dec 20 19:20:50 2018, awade, DailyProgress, WOPO, Diabolo: trialing SHG oven set temperature points to see if there is a maxima when locked plot20181220_SHGLockedOutputVsOvenSetpointTemperature.pdf20181220_SHGLockedPowerVsSetPointTemp.zip
                      Reply  Fri Dec 21 15:33:26 2018, Koji, DailyProgress, WOPO, Diabolo: trialing SHG oven set temperature points to see if there is a maxima when locked 
                         Reply  Fri Dec 21 15:51:27 2018, awade, DailyProgress, WOPO, Diabolo: trialing SHG oven set temperature points to see if there is a maxima when locked 
                      Reply  Mon Dec 24 10:08:49 2018, awade, DailyProgress, WOPO, Diabolo: back to power with deliberate pre-misalignment 18-12-21_22-04-30_4812.jpg18-12-21_22-04-54_4813.jpg18-12-21_22-07-55_4814.jpg
                         Reply  Mon Dec 24 12:07:18 2018, Koji, DailyProgress, WOPO, Diabolo: back to power with deliberate pre-misalignment 
Message ID: 2284     Entry time: Thu Dec 20 19:20:50 2018     In reply to: 2283     Reply to this: 2286   2289
Author: awade 
Type: DailyProgress 
Category: WOPO 
Subject: Diabolo: trialing SHG oven set temperature points to see if there is a maxima when locked 

The strategy locking at lower laser power and optimizing phase matching temperature by slowly walking the temperature and laser power up won't work: the autolocker mode of the Diabolo SHG won't engage at lower laser power. Instead I tried a brute force approach of stepping temperature and re-locking the cavity in 0.05 C increments of set point temperature.  I've plotted the result below.  Error bars are based on standard deviation on 32 averaged measurements over 10 seconds.

I stopped at 106.00 C as  power output was not improving beyond that point. Maximum temperature is clipped at the controller at 110.26 C. Peak output of 66 mW is actually  at 110.20 C. This is counterintuitively higher than the previous set point but might be good enough to work with, as long as its stable over longer periods.

Still not clear what has changed to shift the ideal SHG over set point to 1.4 C higher than it was before.  Maybe the SHG oven needs to go even a little hotter, but we can only access tempertures up to 110.26 C. I'll take what I can get.

Some other laser settings: 

  • Injection current: 2.077 A
  • Laser crystal temperature: 26.32 C
  • SHG PDH gain: 0.5
  • PDH offset: 4.95
  • Noise eater: off

Data and plotting notebook are attached in a zip below: 20181220_SHGLockedPowerVsSetPointTemp.zip

Attachment 1: plot20181220_SHGLockedOutputVsOvenSetpointTemperature.pdf  70 kB  | Hide | Hide all
plot20181220_SHGLockedOutputVsOvenSetpointTemperature.pdf
Attachment 2: 20181220_SHGLockedPowerVsSetPointTemp.zip  6 kB
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