I will admit that I didn’t read the entire writeup, (I can’t stand it when people frame documents inside another page…) but it looks like the majority of the project was to determine the beam profile of the laser, which can be done with a CCD (no lens, just a bare ccd) and a suficient attenuator… An old security cam (that you can manually set the exposure time on) and capture card with a few layers of neutral density filters should get you plenty of info about the beam quality…

Posted at 12:56 am on Feb 18th, 2007 by ...

Whoa, now where are those sharks, so we can put the fricken laser beams on their head?

Posted at 1:29 am on Feb 18th, 2007 by Shadyman

Unfortunately, the formatting of the word document isn’t much better.

After reading through the experimental procedure and results sections, the goal of the project was to analyze the spot profile at focus, not the cross-section before focusing. Many times laser aberrations only become apparent at focus, so imaging the beam before focus only gives an estimate of the focal spot.

The choice of setup is a little strange. His experiment operates under the assumption that with a fast oscilloscope, your temporal resolution (times a constant velocity) is better (cheaper) than the comparable spatial resolution of a translation stage. However, he runs into timing and signal amplitude problems with leads to trouble with triggering and noise. Overall it’s an interesting way to measure a high power focal spot with resorting to equipment in the $10k range.

Posted at 6:42 pm on Feb 18th, 2007 by Chuck