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Entry  Wed May 17 18:08:45 2017, Dhruva, Update, Optical Levers, Beam Profiling Setup 1.jpg2.jpg3.jpg4.jpg5.jpg
    Reply  Mon May 22 10:53:02 2017, Dhruva, Update, Optical Levers, Beam Profiling Results  6x
       Reply  Tue May 23 10:27:24 2017, Dhruva, Update, Optical Levers, Beam Profiling Results  6x
          Reply  Tue May 23 15:22:04 2017, rana, Update, Optical Levers, Beam Profiling Results  
             Reply  Tue May 30 18:31:54 2017, Dhruva, Update, Optical Levers, Beam Profiling Results  plots.pdfspot_size_y.pdf
                Reply  Thu Jun 8 12:43:42 2017, Dhruva, Update, Optical Levers, Beam Profiling Results  profile.pdf
          Reply  Tue May 23 16:33:00 2017, Steve, Update, Optical Levers, Beam Profiling Results  
Message ID: 13002     Entry time: Mon May 22 10:53:02 2017     In reply to: 12997     Reply to this: 13006
Author: Dhruva 
Type: Update 
Category: Optical Levers 
Subject: Beam Profiling Results  

 

Quote:

Andrew and I set up the razor blade beam profiling experiment for He-Ne lasers on the "SP" table.  Once I receive the laser safety training, I will make power measurements and fit it to an erfc curve from which I will calculate the gaussian profile of the beam. I'm attaching some pictures of the setup. 

Least count of the micrometer - 2 microns 

Laser  : Lumentum 22037130:1103P

Photodetector : Thor Labs PDA100A

I had measured the y-profile of the beam of Friday at 5 axial locations and fit them to an erfc function using the lsqcurvefit function of MATLAB. 

The results were as follows - 

z(cm)    w (in)

4          0.0131

10        0.0132

15        0.0137

20       0.0139

25        0.0147

I left w in inches in the intensity plots as MATLAB gave more accurate fits for those values.

I converted these to S.I while making the spot-size vs z plot and the corresponding values in microns were 

332.74, 335.28, 347.98, 353.06, 373.38.

On fitting these values to the formula for the spot size of a Gaussian beam, the beam waist came out to be 330.54 microns and the location of the beam waist was at z=-2cm, where z=0 marks the head of the laser. 

 

TO-DO : Measure the spot size of the beam at more axial points to obtain a better fit. 

              Measure the x-profile of the beam. 

              Analyse the error in the spot sizes and corresponding error in the beam waist. 

 

 

Attachment 1: spot_size_.pdf  8 kB  Uploaded Mon May 22 11:57:42 2017  | Hide | Hide all
spot_size_.pdf
Attachment 2: z_25.pdf  39 kB  Uploaded Mon May 22 11:58:07 2017  | Hide | Hide all
z_25.pdf
Attachment 3: z_20.pdf  37 kB  Uploaded Mon May 22 11:58:07 2017  | Hide | Hide all
z_20.pdf
Attachment 4: z_15.pdf  45 kB  Uploaded Mon May 22 11:58:07 2017  | Hide | Hide all
z_15.pdf
Attachment 5: z_10.pdf  37 kB  Uploaded Mon May 22 11:58:07 2017  | Hide | Hide all
z_10.pdf
Attachment 6: z_4.pdf  37 kB  Uploaded Mon May 22 11:58:07 2017  | Hide | Hide all
z_4.pdf
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