Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
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Resonant optical susceptibility<br />
<br />
For resonant interaction of an isotropic medium with a<br />
monochromatic plane optical field at a frequency = 2,<br />
we have<br />
E(t) Ee it E *e it<br />
P r es<br />
(t) 0<br />
( res<br />
()Ee it * res()E *e it )<br />
<br />
where P res is the polarization contributed by the resonant<br />
transitions and res is the resonant susceptibility.<br />
The time-averaged power density absorbed by the medium is<br />
P<br />
2 <br />
W<br />
p<br />
E 2<br />
0"<br />
res<br />
( )<br />
| E | "<br />
res<br />
( )<br />
I<br />
t<br />
nc<br />
t<br />
39