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Entry  Wed Nov 18 17:49:05 2020, Paco, DailyProgress, Optics, beam profiles 2020_11_18_ecdlprofile.png2020_11_18_mephistoprofile.png
    Reply  Mon Dec 21 16:35:14 2020, Anchal, DailyProgress, Optics, Took beam profile of laser right off the head LaserHeadBeamProfileAvg.pdfLaserHeadBeamProfileX.pdfLaserHeadBeamProfileY.pdf
       Reply  Tue Dec 22 15:54:03 2020, Anchal, DailyProgress, Optics, Took beam profile of near EOM area BeamProfileNearEOMAvg.pdf
          Reply  Mon Dec 28 15:51:51 2020, Anchal, DailyProgress, Optics, Mode matching solution for Cavity Solutions1-7merged.pdf
             Reply  Thu Dec 31 16:41:59 2020, Anchal, DailyProgress, Optics, Mode matching solution for Cavity Solutions.pdf
                Reply  Wed Jan 6 09:34:34 2021, Anchal, DailyProgress, Optics, Corrected analysis and found better solutions. Solutions.pdf
                   Reply  Fri Jan 8 17:00:26 2021, Anchal, DailyProgress, Optics, Included lens made by cavity input mirror and distrotion due to crystal Solutions.pdf
                   Reply  Fri Jan 8 17:17:19 2021, Anchal, DailyProgress, Optics, Included lens made by cavity input mirror and distrotion due to crystal Solutions.pdf
                      Reply  Tue Jan 26 11:33:32 2021, rana, DailyProgress, Optics, Included lens made by cavity input mirror and distrotion due to crystal 
                      Reply  Tue Jan 26 11:34:51 2021, rana, DailyProgress, Optics, Included lens made by cavity input mirror and distrotion due to crystal 
Message ID: 1884     Entry time: Mon Dec 28 15:51:51 2020     In reply to: 1882     Reply to this: 1886
Author: Anchal 
Type: DailyProgress 
Category: Optics 
Subject: Mode matching solution for Cavity 

Goals and restrictions:

  • Use the fewest lenses as possible.
  • The beam widths in both onward and reflection direction should be such that there is a 5-inch space somewhere where we can put in the faraday isolator which has an aperture size of 3 mm and intensity limit of 500 W/cm2.
  • The lens should not be closer than 1.5 inches from each other or to the EOM mount or cavity edge.
  • Choose a lens from a list of focal lengths available in west bridge labs.
  • Find the best overlap with the target beam of 18 um at the cavity waist with the most sensitivity with respect to lens positions.

Analysis & Results

  • CavityLens.m is run to try all possible lens combinations for 2-lens or 3-lens solutions using ../20201222_BeamProfileNeatEOM/SeedBeam.mat as the seed beam.
  • Then save solutions with more than 70% overlap in CavityModeMatchingSolutions.mat.
  • findBestSolutions.m increases the overlap threshold to 0.9, calculates reflected beam profile for the sideband reflection from the cavity (blue curves in the figures), and discards solution which does not have a 5-inch long area where we can place a faraday isolator with aperture of 3 mm.
  • Black lines show the region where Thorlabs IO-3-1064-HP can be placed safely without clipping or exceeding the intensity limit with 1W power.
  • All solutions in order of sensitivity are plotted here with details of lens choice and positions. In total 7 solutions were found which are stored in BestSolutions.mat.

Analysis & Data


Wed Jan 6 10:00:35 2021: This analysis was wrong. See SUS_Lab/1887.

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