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Message ID: 1639     Entry time: Thu Jun 9 20:35:41 2016
Author: awade 
Type: Notes 
Category: Laser 
Subject: Characterizing the beam profile out of the M126N-1064-500 (500 mW NPRO) laser 

Its taken me a while to get to posting this.

I took a pick off of the main beam coming out of the 500 mW laser using a coated fused silica window (W1-PW-1037-UV-1064-45 UNP) and used the WinCamD camera to find the profile as a function of distance.  The difficulty with the measurement is reducing the power enough for the CCD and fitting around the already aligned components.  Unfortunately there are already two wave plates and a steering mirror in the path that are already aligned to a mode cleaner etc that can't/shouldn't be moved. The profile measurements are therefore at quite some distance from the laser head.

Set up with lengths is in attached schematic. Fitted data (referenced to the front of the laser head) is in other attached fit. Data is as follows:

z= [0 20 40 75 105 130 160 190 230 270 310 350]*1e-3 + (123e-3+35e-3+52e-3); % Distance from reference point plus distance to laser head
W_horz = [776.6 849.2 915 1048 1140 1218 1333 1427 1556 1704 1828 1905]*1e-6/2; %Horizontal beam radius
W_vert = [1259 1349 1349 1475 1615 1707 1751 1895 2099 2218 2413 2554]*1e-6/2; % Vertical beam radius

--

Fit gave the following values:

Horz. beam waist = 194.7896 um
Horz. beam waist position = 9.07 mm
Vert. beam waist = 177.6142 um
Vert. beam waist position = -97.3669 mm

Note sure about the vertical waist position there. But those are the fitted values.

Other information pertinent to the measurement is that the laser power measured at the output of the M.A.-1064-500 head was 171.3 mW.  This was just the value it was set at, that I assume was chosen for a reason.  Varying the power from this value may change beam characteristics.  

It would be nice to have measured closer to the output of the laser, but this is not possible without disturbing the rest of the ongoing experiment.

Attachment 1: ModeMeasurmentCTN500mWEPRO.pdf  802 kB  | Hide | Hide all
ModeMeasurmentCTN500mWEPRO.pdf
Attachment 2: 20160609GaussModeMeasurementCTN500mWNPRO.eps  969 kB  | Hide | Hide all
20160609GaussModeMeasurementCTN500mWNPRO.eps
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