Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
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Four-level pumping<br />
<br />
In most four-level systems, the nonradiative decay component<br />
in the 2 to 1 transition is negligible ( sp > sp<br />
>> 1 , s.t.<br />
N 0<br />
R sp<br />
s<br />
sp<br />
And therefore<br />
N <br />
R sp<br />
1 sp<br />
W i<br />
<br />
We have assumed that the pumping rate R is independent of<br />
the population difference N = N 2 –N 1 .<br />
93<br />
93