Does a light pulse get amplified when it goes to a less dense medium?


by quantum123
Tags: amplified, dense, light, pulse
quantum123
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#1
Jan16-10, 06:57 AM
P: 312
Since a string pulse get amplified when it enters a less dense medium such as from the thick heavy rope to a lighter string, why does not light do the same?
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jety
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#2
Jan16-10, 07:14 AM
P: 9
Try reading this thread http://www.physicsforums.com/showthread.php?t=66629.
quantum123
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#3
Jan16-10, 08:16 AM
P: 312
Come to think of it, there is a medium and the medium is the electromagnetic field.

jety
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#4
Jan16-10, 08:23 AM
P: 9

Does a light pulse get amplified when it goes to a less dense medium?


It never goes to a "different medium".
Bob S
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#5
Jan16-10, 01:08 PM
P: 4,664
When light goes from a medium such as glass (index of refraction n=1.5) to air, about 4% of the energy is reflected, and 96% of the energy is transmitted. The ratio of the transverse E (electric) vector to the transverse H (magnetic) vector in light is proportional to 1/n, so the ratio E/H increases when the light goes from glass to air. But the transmitted energy decreases by 4%. So the amplitude E increases, but the transmitted energy, which is proportional to E times H (Poynting vector), decreases.
Bob S
quantum123
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#6
Jan16-10, 08:56 PM
P: 312
Thanks, Bob!


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