请教问题3

Consider the energy levels involved in the operation of a He-Ne laster. Consider the lifetimes of the various levels. Which should be long, which sould be short. Explain why the actual laser transition is weak in luorescence by looking at the He-Ne laser rom the side.

If the small signal gain of the Ne gas, with inversion, inside the laser medium is 0.003m-1, and the loss due to all processes is 0.001m-1. How much total gain would occur for a laser 300mm long.?

If you shine a beam from a second laser tuned to resonance along the medium with an imput intensity of I(0)-what would the intensity be at the output?Does this result depend on I(0)? What would happen in the limit of very small I(0)? what will happen when we increase I(0)?(Consider the rate equations)