Question 1: At any given time, the number of photons inputted into the cavity must be equal to the number that have passed through the cavity without exciting an atom plus the number still in the cavity plus the number of excited atoms. Verify this conservation law by stopping the simulation and counting photons.
This formula can describe the behavior of the photons where N represents photon, N_in = N_Out + N_Miss + N_Excited.
In the picture below it corresponds to 12 = 0 + 3 + 9
Question 2: During spontaneous emission, does there appear to be a preferred direction in which the photons are emitted?
The photons leave in any direction, they do leave in a preferred direction.
Question 3: Does there appear to be a constant amount of time in which an atom remains in its excited state?
No, The photons are not excited for a certain amount of time, they will leave at random times.
Question 4: Carefully describe what happens when a photon interacts with an excited atom. Pay careful attention to the phase and direction of the subsequent photons. (Can you see why this is called stimulated emission?)
The photons will collect energy from the excited atoms, this effect will continue if the photon hits more excited atoms.
Question 5: Approximately what pumping level is required to achieve a population inversion? Remember, a population inversion is when the number of atoms in the excited state is at least as great as the number of atoms in the ground state.
A pumping level of about 75 is enough for population inversion to occur.
Question 6: Although most photons are emitted toward the right in the simulation, occasionally one is emitted in another direction. Are the photons emitted at odd directions the result of stimulated or spontaneous emission?
It is the result of spontaneous emission.
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