Population Inversion: Pumping Wavelength for 3.5 eV Energy Difference

[Aoiumi]

Homework Statement

In order to achieve population inversion between two states that are separated by an energy difference of 3.5 eV, what wavelength of pumping should be used.

Homework Equations

Not sure.

The Attempt at a Solution

I have no idea where to start with this one. Can someone please point me in the right direction? There were no forumulas given. Thank you!

 

[SammyS]

Homework Statement

In order to achieve population inversion between two states that are separated by an energy difference of 3.5 eV, what wavelength of pumping should be used.

Homework Equations

Not sure.

The Attempt at a Solution

I have no idea where to start with this one. Can someone please point me in the right direction? There were no formulas given. Thank you!

How do the atoms/molecules get energy to get into the higher energy state.