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Entry  Wed Jul 14 14:39:09 2010, Dmass, Laser, PSL, H1 NPRO Measured NPROWaist.pdf
    Reply  Thu Jul 15 15:41:40 2010, Dmass, Laser, PSL, H1 NPRO Measured 
       Reply  Fri Jul 16 18:54:57 2010, Dmass, Laser, PSL, H1 NPRO Measured H1ModeMSoln.pdf
          Reply  Sat Jul 17 01:41:20 2010, Koji, Laser, PSL, H1 NPRO Measured 
          Reply  Wed Jul 21 20:13:06 2010, Dmass, Laser, PSL, H1 NPRO Measured H1NPRO_AM.png
             Reply  Thu Jul 22 16:19:48 2010, Koji, Laser, PSL, H1 NPRO Measured 
             Reply  Fri Jul 23 00:45:46 2010, Dmass, Laser, PSL, H1 NPRO Measured 
                Reply  Tue Jul 27 00:10:20 2010, Dmass, Laser, PSL, PMC Calibrated PMCCtrl.pdf
             Reply  Tue Jul 27 19:04:35 2010, Dmass, Laser, PSL, H1 NPRO Measured NproPZTFMBode.pdf
                Reply  Wed Jul 28 19:51:10 2010, Dmass, Laser, PSL, H1 NPRO Measured IMG_0241.png
                   Reply  Fri Jul 30 16:48:11 2010, Dmass, Laser, PSL, H1 NPRO Measured 
                      Reply  Sun Aug 1 18:37:07 2010, Dmass, Laser, PSL, H1 NPRO Measured 
                   Reply  Mon Aug 2 00:46:13 2010, Dmass, Laser, PSL, H1 NPRO Measured Picture_2.png
    Reply  Mon Aug 2 22:23:36 2010, Dmass, Laser, PSL, H1 NPRO Measured H1MM2PMC.pdf
    Reply  Tue Aug 3 01:31:15 2010, Dmass, Laser, PSL, H1 NPRO Measured H1NPROWaist2.pdf
       Reply  Tue Aug 3 13:47:55 2010, Dmass, Laser, PSL, H1 NPRO Measured Npro2PMCmm.pdf
       Reply  Tue Aug 3 17:27:20 2010, Dmass, Laser, PSL, H1 NPRO Measured 
Message ID: 857     Entry time: Sat Jul 17 01:41:20 2010     In reply to: 855
Author: Koji 
Type: Laser 
Category: PSL 
Subject: H1 NPRO Measured 

In terms of the damage of the optics, I have never seen the CVI mirror is damaged by this level of the power density.

What I have seen was a newport BK7 cube BS melting with the 10W focused on the <100um waist radius.

Quote:

This thing really didn't want its modes matched. I had to open up a can O' parameter space on it. Notas:

  • I added a static lens in front of the NPRO as well to change the mode I was working with
  • I extended the path length (will have to use some folding mirrors)
  • I checked that dwaist/dposition was dominated by one of the mirrors by about a factor of ten, so I might actually be able to fiddle with them easily once theyre in place and the PMC is locked.
  • I tried to avoid making any nasty waists on the table, the one that does exist is bigger than 100 um radius, and MAY PASS OVER WHERE I HAVE A MIRROR CURRENTLY!

 

121 um waist with 1.5 Watts is about 3*10^3 W/cm^2 - is this fine to sit pretty much on a mirror,

  • Damage thresholds for CVI coatings seem to have several to 10 "J/cm^2" for 20 nanosecond 1064 nm pulses\
    • This means it can take 500 MW/cm^2 for 20 ns - unless I know how often these pulses happen I'm not sure how to make this a CW number
    • To turn this into a normal number I assume I just do "1 J / pulse lase rate / cm^2" - I have no idea what rates are common for pulsed lasers
  • CW damage thresholds of materials seem to be order "MW/cm^2" - and if these are what's quoted by a company, it would seem that their coatings would have to not be many orders worse than this (or else the number would be meaningless) - though these companies have done other ridiculous *&!# before so...

I would appreciate any input from the peanut gallery - for now I am inclined to think that 1.5W on an HR mirror with a 240 um spot size is fine.

 

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