Straight Edge Diffraction Pattern of Uniform disk sources

Finally, the program seems to be working, and my graphs seem to be agreeing pretty well with that of Dr. Michael Richmond’s results.

Here are the graphs I got, generated using GNUPlot:

[License: GPL.]

The results seem to agree well. The source code should be up sometime on http://dev.bas.org.in/main_rep – but that’ll still take time. Mail me if you want the source. Of course, it’s licensed under GPL.

LASER diffraction off a CD-ROM

I recently took a photo of LASER diffraction off a CD. Some of my friends (and I) liked it, so I thought it should appear on my blog as well. So here it is:

I’ve labelled the various beams that you see in the photograph in this version:

Trivia: Why is the second maximum beam (n=2) brighter than the first maximum beam (n=1)?

I was able to roughly estimate that the CD’s tracks are about a micrometre apart and that the pits containing the data are either further apart than that, or show a regularity on a larger scale than that. Need to do some more qualitative experiments on that.

The photo is a 15 second exposure at f/3.5 @ ISO 1600. Released to public domain. Credits requested.