Why does a laser scatter when shining on skin?

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Why does a laser scatter when shining on skin?
« on: 05/04/2011 06:30:03 »
Michael  asked the Naked Scientists:
Hey Chris

Since discovering your website/podcasts (by way of our local Cape Town radio station 567 Cape Talk/702) I've become an avid downloader; particularly interested in cosmology and evolution (a big Dawkins fan).
My Question:
When I shine a laser dot on any inanimate object, it reflects a nice tight/bright spot (as it "should") but when I shine it on pet fur, it dissipates into a "blotch" That I understand -  the fur would act as filaments, presumably creating a sort of "fibre optic'; What I don't understand was that when I shone it on my skin (hand/forearm), it did the same thing - become a big fuzzy blotch.

This got me wondering what could cause the scatter. It could only occur after contact (duh?!) & my assumption is therefore that either the laser light is piercing the skin at the perpendicular angle, being scattered sub-subcutaneously, and illuminating the deeper layers, or it scatters laterally upon contact (perhaps through the fine hairs that are not visible to naked the eye).
My real question then is whether living flesh impacts the path of laser light in some specific way. Or is something more elementary and obvious going on?

Michael Smorenburg

What do you think?
« Last Edit: 05/04/2011 06:30:03 by _system »


Offline yor_on

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Why does a laser scatter when shining on skin?
« Reply #1 on: 05/04/2011 07:43:15 »
This one discuss it. Laser tissue interactions.
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