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Entry  Sat Apr 17 18:30:12 2010, Zach, Update, Green Locking, 1W NPRO output profile profile_fit_4_17_10.png
    Reply  Mon Apr 19 11:31:04 2010, Aidan, Update, Green Locking, 1W NPRO output profile 
Message ID: 2804     Entry time: Sat Apr 17 18:30:12 2010     Reply to this: 2807
Author: Zach 
Type: Update 
Category: Green Locking 
Subject: 1W NPRO output profile 

NOTE: This measurement is wrong and only remains for documentation purposes.

Koji asked me to take a profile of the output of the 1W NPRO that will be used for green locking. I used the razor-scan method, plotting the voltage output of a PD vs the position of the razor across the beam, both vertically and horizontally. This was done at 6 points along the beam path out of the laser box.

I determined the beam spot size at each point by doing a least-squares fit on the plots above in Matlab (using w as one of the fitting parameters) to the cumulative distribution functions (error functions) they should approximate.

I then did another least-squares fit, fitting the above "measured" beam profiles to the gaussian form for w vs z. Below is a summary.

It seems reasonable, though I know that M2 < 1 is fishy, as it implies less divergence than ideal for that waist size. Also, like Koji feared, the waist is inside the box and thus the scan is almost entirely in the linear regime.


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