Molecules: You'd better learn to live with them.
I just love this. Ever wonder how a rewritable CD works?
AgInSbTe is just an alloy of the four metals. When you heat it with rapid bursts of intense laser light, you get amorphous AgInSbTe (not very reflective). When you heat it with long pulses of low-intensity laser light, you get crystalline AgInSbTe (reflective). Get the intensity, beam size, and pulse length just so, and you can make discrete areas that reflect laser light (of a much lower intensity) to a much different extent. There's your ones and zeroes, there's your CD.
When you're done with it and want to rewrite, just blank everything to amorphous AgInSbTe and you have all zeroes again.
This phase-change trick only works about a thousand times, by which point you've (hopefully!) scratched or lost it anyway.
Comments
Just an FYI, Sb is antimony, Sn is tin. Great blog though!
Posted by: The Mad Alchemist | May 9, 2007 10:19 PM
My mistake, thanks.
Posted by: Molecule of the Day | May 9, 2007 11:06 PM
ooooh neato. who would have thought there'd be such a simple explanation for all of that. Now I guess you just need to build the laser and computer that reads the thing...
Posted by: Brando | May 10, 2007 5:00 PM