- #1
cupid.callin
- 1,132
- 1
Hi all,
I was reading Lasers and i read something like this:
for spontaneous emission, the rate of decay of electrons in high-energy state to low energy state is given by:
[itex]\frac{dN_2}{dt} = P_{21}N_2[/itex]
where P21 is equal to the probability of electron to drop from higher energy state to lower energy state.
Now, P21 was defined as [itex]P_{21} = B_{21}u(\nu)[/itex]
And [itex]B_{21}[/itex] is called Einstein's Coefficients of spontaneous emission
then in some other topic, they wrote B21 as probability of spontaneous emission per unit time.
Are they really same thing? ... I guess not ... B21 should be something like probability of spontaneous emission per-unit Energy density (:p i know this doesn't make any sense ... ) ...
Please Help ...
I was reading Lasers and i read something like this:
for spontaneous emission, the rate of decay of electrons in high-energy state to low energy state is given by:
[itex]\frac{dN_2}{dt} = P_{21}N_2[/itex]
where P21 is equal to the probability of electron to drop from higher energy state to lower energy state.
Now, P21 was defined as [itex]P_{21} = B_{21}u(\nu)[/itex]
And [itex]B_{21}[/itex] is called Einstein's Coefficients of spontaneous emission
then in some other topic, they wrote B21 as probability of spontaneous emission per unit time.
Are they really same thing? ... I guess not ... B21 should be something like probability of spontaneous emission per-unit Energy density (:p i know this doesn't make any sense ... ) ...
Please Help ...