Can stimulated emitted photons be absorbed? Typically a stimulated photon will be one of a pair with its stimulating photon. 
If the leading photon is absorbed by a particle in the ground state, will it then be re-emited by the stimulated emission caused by the second photon? 
If it causes a stimulated emission from an excited particle, will there then be a train of three photons, or will the new pair leave the excited particle excited? 
I am interested in the case where there is not a population inversion, but presumably the same rules would apply to lasers.
 A: Check out the Einstein equations (wikipedia page, also the pages on stimulated and spontaneous emission).  The probability of emission is the same as the probability of absorption.  The probabilities of either type of emission are independent of the population inversion.
Photons which entered the system are indistinguishable from the ones generated either thru stimulated or random emission (aside possibly from phase & polarization).   Similarly, there's no way to tell an excited particle state caused by photon absorption from the same state caused by any other mechanism.
A: In stimulated emission, energy is added to the existing radiation field.  It does not create a new field at a later time.   The field contains one additional quantum of excitation.  That's a single state of the field with a higher "occupation number". 
In other words, you don't end up with two photons, one after the other. 
A: The energy is not conserved in the situation you describe: you start with two photons and a particle in the ground state, and you end up with three photons and a particle in the ground state.
If the first photon excites the particle and the second causes stimulated emission, you end up with two identical photons. In fact, you will not be able to distinguish if this excitation-emission happened at all, or if photons didn't interact with the particle.
