# Metable states in a Laser

1. Jul 4, 2012

### Blogical

I wonder whether an electron can make a transition from one metastable state to an another metastable state, if so it leads to a paradox(atleast according to me) viz for the refrence frame of the metastable state A from which electron makes the transition, it will be a radiative transition and for the refrence frame of the metastable state B to which the electron makes the transition, it will be a non-radiative transition!
It does not make sense.
Forgive me for being naive, i have no formal degree in Physics, but i like it a lot!

2. Jul 4, 2012

### Cthugha

Ehm...I do not get your point.

A metastable state is one that is not perfectly stable, but has a very long decay time (microseconds or even milliseconds). That is all there is. Proposing "reference frames of metastable states" does not make much sense. The transition may be radiative or not - for lasers it typically is, but that does not depend at all on whether the final state of the transition is metastable or not.

3. Jul 4, 2012

### shawl

I do not get your point, either. Here's my suggestion.

Metastable state is in company with a certain state. In general, there is a small gap between their energy levels (Metastable level belows certain one).

Given 2 certain states, A and B, and suppose their have some metastable states company with, such as (metastable states) A1 and A2 for A state, B1 and B2 for B state.

The transitions between A to A1(A2) or A1 to A2, or B to B1(B2), or B1 to B2, are usually non-radiative. The energy leaks through the thermal diffusion.

But the transitions between A1 to B or A1 to B1(B2) are radiative, it radiates a light with certain energy of (A1-B)

4. Jul 5, 2012

### Blogical

As u have said that A1 to B1 is radiative and A1 to A2 is non-radiative, my doubt is that how does an electron which is in A1 and is about to make a transition, know WHICH IS A2 OR B1 , for the electron it only experiences the life-time of these states and hence we can distinguish between normal state and metastable state, as both are metastable states their life-time would be the same.

5. Jul 6, 2012

### shawl

A1 to B1 belongs to quantum dynamics, and A1 to A2 is due to thermal diffusion.
Eletron itself doesn't know which state it should go, but the detail physical process will decide where the electron is going