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Message ID: 1646     Entry time: Mon Jun 20 12:18:50 2016
Author: awade 
Type: DailyProgress 
Category: Laser 
Subject: Beam profiles of North EPRO (M126N-1064-700) 

A pickoff of the 700 mW north laser was made with two UV grade fused silica widows to make a beam profile measurement.  Attached figure shows setup.  

Here the data is for the North laser (measured on June 17 2016) operating at 701.1 mW (Adj number = 0).  The laser was allowed time to warm up and a pickoff of the beam was taken by first reflecting off the front surface of a W1-PW1-1025-UV-1064-45UND UV grade fused silica window and then a W2-PW1-1037-UV-45P UV grade fused silica window with AR coating on front and back: the resulting light was ~200 uW. Beam widths as a function of distance were collected using the WinCamD after isolating a single spot with an iris.  Because of the need for two windows, it difficult to sample less than 150 mm from the laser head.

 

The data is as follows:
z= [0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425]*1e-3 + (72e-3+25e-3+62e-3);
% Distance from the laser head. The fixed added on value at the end is the distance to the first measurement point
W_horz = [768 829 866.2 915.7 965.3 1018.0 1072.3 1135.7 1180.0 1231.7 1285.1 1346.9 1402.5 1462.6 1517.0 1568.1 1648.3 1700.1]*1e-6/2; % Horizontal beam radius
W_vert = [760.4 762.8 870.1 971.8 983.2 1119.2 1223.5 1231.2 1353.5 1428.1 1522.5 1558.4 1619.4 1729.9 1813.9 1856.0 1888.6 1969.1]*1e-6/2; % Vertical beam radius

The fitting routine, plot and schematic of setup are attached.

--

The fit to the data gave:
Horz. beam waist = 272.6917 um
Horz. beam waist position = -62.2656 mm
Vert. beam waist = 213.3873 um
Vert. beam waist position = -36.3761 mm

For some reason the horziontal data looks noiser, I'm not sure what is happening there.

 

 

-awade Mon Jun 20 12:16:23 2016

Attachment 1: ProfileMeasurmentNorthLaserSetup.eps  2.168 MB  | Hide | Hide all
ProfileMeasurmentNorthLaserSetup.eps
Attachment 2: data20160617_NorthLaserBeamProfileDataAndFit.m  2 kB  | Hide | Hide all
%% Fitting routie for beam profiling measurments
%
% This model takes a set of data values for scaned beam widths as a
% function of distances an computes the waist and its position using the
% GaussProFit routine.  

clear all % clear the decks
close all

addpath('~/Box Sync/TCNlab_shared/standardMatlablibrary/') % Adds path to standard Matlab functions used for the TCN labwork
... 53 more lines ...
Attachment 3: plot20160617_NorthLaserBeamProfileDataAndFit.eps  136 kB  | Hide | Hide all
plot20160617_NorthLaserBeamProfileDataAndFit.eps
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