I discovered that when I burn through a CD case with my 300mW green laser, the following effect is produced on the wall:
Full pic: http://jwcxz.com/projects/lasers/halos.jpg
Video:
http://www.youtube.com/watch?v=Wy3oR6fY6W8
At first, I didn't know what this was caused by, but I found this on Google:
http://frank.mtsu.edu/~phys2020/Lectures/Part_1__L1-L5/Lecture_5/Apertures/apertures.html
http://en.wikipedia.org/wiki/Airy_disk
Is this what I'm seeing? Or am I totally wrong?
Full pic: http://jwcxz.com/projects/lasers/halos.jpg

Video:
http://www.youtube.com/watch?v=Wy3oR6fY6W8
At first, I didn't know what this was caused by, but I found this on Google:
http://frank.mtsu.edu/~phys2020/Lectures/Part_1__L1-L5/Lecture_5/Apertures/apertures.html
http://en.wikipedia.org/wiki/Airy_disk
Is this what I'm seeing? Or am I totally wrong?