So, this week so far is turning out alright, but not too much blogging material, so this will be a pretty short post (I hear you say "Oh thank goodness"). So, on Monday, I started to analyze the YAG laser for another characteristic: divergence. So, to do that I needed this bulky component:
What in the world in that, you ask? Well, let's take a closer look one of the knobs:
That should have given it away. This device allows you to move an object in very small and consistent intervals, and in either the x, y, or z direction. How small? In the picture above, from 0 to 10 is 1 inch. Then, between each integer is split into 4 intervals. Then, the top knob is split into 25 intervals. So, 1 inch, divided into 10 intervals, then 4, then 25, means that one interval on the knob is 1/1000 of an inch, or 1 mil! No, not million, mil. Yes, it's an actually unit. In metric, 1 mil is 25.4 microns.
So, to find divergence, or the angle at which the laser beam expands, you measure the beam radius a known distance apart, then it's just simple geometry to find the angle. However, measuring the beam radius may have been the MOST TEDIOUS THING EVER. To find the beam radius, you attach a razer blade to this device, and then you move it across the beam path while measure the laser's power. As you cover up more of the laser, the lower the power is measured (that should make sense), and then you graph Power vs Position, then do some crazy math (that I'm not going to explain) to find the radius. However, it's the measuring that's tedious. What happens is that you have to take a measurement every interval of the knob. So, say that beam was between 6 and 8 on the scale (which it approximately was). 8 minus 6 is 2, and 2 times the 4 intervals, times the 25 intervals, is 200 measurements! That takes FOREVER. Like, turn knob, mark down power, turn knob again, mark down, etc, 200 TIMES! Also, even though I only needed to do this 3 times, I screwed up twice, for a total of 5 times 200, which is 1,000 measurements. Ugh. Anyways, the data turned out pretty well, so at least payed off a little (*cough cough* psychology *cough cough*). That pretty much took up Monday to today, Wednesday. Some pictures of the experiment:
Laser is uncovered. Note the green dot in the foreground is on the power meter.
About halfway covered. This green dot on the power meter is smaller, and the other green dots are on the razor.
Laser is completely covered. All on the razor, no laser light reaches the power meter. The number on the power meter is it reading the ambient light.
Yeah, so I have to present my findings during a meeting on Friday, so I'm sort of nervous for that. So, for some other interesting things, we have yet ANOTHER Linux convert, Cory left for Atlanta on Tuesday, where he'll give a talk of some kind, and be back on Monday. Brittany only comes on Mondays, Wednesdays, and Fridays. Which means that on Thursday I have the lab ALL TO MYSELF! MUWAHAHA! Not like I'm going to do anything bad or anything.... Actually, I left out some things in this post so I can make the Thursday and Friday's post longer, since with probably nothing happening on Thursday, that would be a scant post, and I can't have that! See, that wasn't that long, was it?
2 comments:
Great post, Joseph.
Was that sarcasm, Johnston?
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