Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Gain coefficient<br />
<br />
<br />
Consider the incremental number of photons per unit area per<br />
unit time, d(z), is the number of photons gained per unit<br />
time per unit volume, NW i , multiplied by the thickness dz<br />
d<br />
<br />
NW dz<br />
In the form of a differential equation<br />
d<br />
dz<br />
( ) (<br />
z)<br />
i<br />
)<br />
where the gain coefficient<br />
2<br />
c<br />
( ) N<br />
( ) N<br />
2 2<br />
8n<br />
<br />
sp<br />
gˆ(<br />
<br />
78