Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
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Transition rates<br />
<br />
<br />
The total induced transition rates<br />
W 12<br />
<br />
W 21<br />
<br />
<br />
W 12<br />
()d B 12<br />
u()ĝ()d<br />
0<br />
<br />
<br />
<br />
0<br />
W 21<br />
()d B 21<br />
u()ĝ()d<br />
0<br />
<br />
<br />
0<br />
The total spontaneous emission rate is<br />
W sp<br />
<br />
<br />
<br />
0<br />
W sp<br />
()d A 21<br />
u()<br />
W 12<br />
= B 12<br />
u()<br />
N 2<br />
|2><br />
W 21<br />
= B 21<br />
u() W sp<br />
= A 21<br />
|1><br />
N 1<br />
21