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.
N(in) = N(out) + # of photons still on the frame + excited atoms
15 = 2 + 1 + 12
Question 2: Direction of
Spontaneous Emission
During spontaneous emission, does there appear to be a preferred direction in which the photons are emitted?
During spontaneous emission, does there appear to be a preferred direction in which the photons are emitted?
No. Photons are emitted in random directions.
Question 3: Lifetime of
Excited State
Does there appear to be a constant amount of time in which an atom remains in its excited state?
Does there appear to be a constant amount of time in which an atom remains in its excited state?
There is no constant amount of time for a single atom.
However, there can be a prediction if a bunch of identical atoms are considered
instead.
Question 4: Stimulated Emission
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?)
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?)
When a photon (which come from the left) strikes an excited
atom, the photons appear to multiply by a factor of 3. The proton is then
driven to their ground state until all of the excited atoms have been hit.
Question 5: Pumping
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.
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 P = 70 is the one that most of the time keeps the number of excited and ground level atoms even.
Question 6: Photon Emission
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?
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?
In a spontaneous emission, the photons are emitted in random directions.
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