M5L24c.txt

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Questions about lasing without inversion?
Nancy?
Is lasing without inversion important in lab?
Like, as opposed to lasing with inversion?
Or is it more about teaching us an important thing?
Well, lasing without inversion has definitely
been touted as a way to get lasing deeper in the UV,
to get lasing for very blue transitions,
because when you want to create inversion,
this actually has been the problem in creating
x-ray lasers in atomic systems.
If you have larger and larger energy separation,
spontaneous emission scales with omega cube,
and so therefore it becomes harder and harder
to fulfill the order gain equation.
So in those cases, even these last two methods
will probably [INAUDIBLE]?
Because they're [INAUDIBLE].

Well, lasing without inversion alleviates a requirement
to build a laser, and so people have discussed that where
it's really hard to create a laser in the conventional way,
deep, deep in the blue, the UV, or in the x-ray regime,
that lasing without inversion may help.
I'm not aware that any practical development
has emerged from that, because there is a price to be paid,
and that is usually in the form of coherence.
You need a certain degree of coherence
in your system to be able to do that,
but it's an idea which is powerful, but as far as I know,
there was no killer application of it.

The importance of dark states is definitely
in slow light, manipulation, quantum computation,
and concepts of storing light, and this