Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
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Gain coefficient<br />
<br />
<br />
<br />
As the incident photons travel in the z direction, the<br />
stimulated-emission photons also travel in this<br />
direction.<br />
An external pump providing a population inversion<br />
N > 0 then causes the photon-flux density (z) to<br />
increase with z.<br />
Because emitted photons stimulate further emissions,<br />
the growth at any position z is proportional to the<br />
population at that position. (z) thus increases<br />
exponentially.<br />
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